Research Project Descriptions
A complete copy of the project descriptions (Including: Approach and Methodology, Results and Accomplishments and Milestone Dates) are available to Center Members in the Members Only section of our website at wimserc.org
Contents:
Micropower Circuits Micropackaging, Microfabrication, and Power Source Technologies Environmental Sensors & Subsystems Biomedical Sensors & Subsystems Wireless Interfaces
Micropower Circuits
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Title:  Design and Implementation of Low-Voltage Analog-Front-End for a Low-Power Cochlear Implant System-on-a-Chip
Graduate Students: Amlan Ghosh (ECE-UT)	Faculty Advisor: Richard B Brown (ECE-UT) Work Began: 01/20/2006
Project Goals:
The primary objective of this project is to design and implement an analog-front-end (AFE) that provides an interface between the transducer and microcontroller unit. State of the art AFE normally consists of signal conditioning circuits, LNA (low noise amplifier) or gain-enhancement circuit and analog-to-digital conversion. In case of actuation, it may also need digital-to-analog converter and drivers. The target application for this converter is chemical sensing which requires high resolution of the order of 12 bits. This system-on-a-chip approach with analog and digital systems on the same die helps in lowing the power dissipation of the system. It also offers advantages in size and weight, which provides the most important attributes of any portable device. This single-chip mixed-signal solution provides benefits of low-power consumption by decreasing the amount of required buffers to drive off-chip loads, including pads and bonding wires and printed circuit board traces.
Title:  Subliminal: An Ultra-Low Energy Sensor Network Processor
Graduate Students: Scott M. Hanson (EECS), Bo Zhai (EECS)	Faculty Advisors: Work Began: 01/01/2005
Project Goals:
To investigate new architectures and circuit structures for applications requiring battery lives on the order of months and years. In particular, our work focuses on the wireless sensor network application space. Within this space, cost and energy reduction are the primary goals, while performance is a secondary concern.
Title:  A Universal Micro-Sensor Interface Circuit for Low-Power Microsystems
Graduate Students: Chao Yang (ECE-MSU), Jichun Zhang (ECE-MSU)	Faculty Advisor: Andrew J Mason (ECE-MSU) Work Began: 05/15/2002
Project Goals:
In ultra-miniature and low power multisensor microsystems, the interface circuitry (signal conditioning and processing) plays an important role in achieving high performance and hence has been identified as a key component in the whole system. This project seeks to develop a full-featured, low-power, single-chip, hardware interface that provides a link between a central processor and a wide range of MEMS sensors and actuators. The chip being developed is called the Universal Micro-Sensor Interface (UMSI). The highly programmable readout circuit is suitable for use in a wide range of sensor microsystems and can be easily expanded for future applications.
Title:  Low Power and Robust Digital Circuit Design
	Work Began: 01/01/2003
Title:  Modeling of Power Supplies for Wireless Integrated MicroSystems
Graduate Students: Fabio Albano (MSE)	Faculty Advisor: Ann Marie Sastry (ME) Work Began: 01/01/2001
Project Goals:
Accurate modeling of power supply requirements demands detailed information about expected system losses and comparison with available energy and power densities in power supplies. This project seeks to develop power supplies for: 1) the cochlear/neural prosthesis testbed and 2) the intraocular testbed.
Title:  Process Tolerant Low-Power Circuit Design
Graduate Students: Harmander S. Deogun (EECS) Funding Source: IBM	Faculty Advisor: Dennis M Sylvester (EECS) Work Began: 01/01/2004
Project Goals:
Working with process variation while simultaneously containing power consumption in digital circuits has now become a ubiquitous design challenge. Recently, designs to adapt for variation in the manufacturing process to contain power and maintain functionality have been introduced. The challenge in adaptive design is to make circuits that do not require large area overheads that are necessary for such circuits as charge pumps, critical path replication or transistor arrays. We propose a novel process sensor which has a low-area overhead and can directly adapt to nearby circuits through a technique we call adaptive MTCMOS.
Title:  Low-Power Compilation
Graduate Students: Rajiv A. Ravindran (EECS)	Faculty Advisor: Scott Alan Mahlke (EECS) Work Began: 01/01/2002
Project Goals:
One of the greatest challenges facing embedded microprocessor designers is dealing with the exponential growth trend in power consumption rates. High power consumption often translates into unacceptable battery lifetimes. An obvious answer is to scale down the performance of the processor until it meets acceptable power dissipation rates. However, this is not a feasible solution as the resultant performance would cause most applications to run unacceptably slow. Thus, it is important to develop a low-power design strategy that can also provide high performance. Much research is being done on the hardware level to vary the supply voltage and frequency needed for circuits or to design new processor architectures that require less power. In this project, we will examine power management at the software level. In particular, we will focus on developing a retargetable, power-aware compiler that enables effective power management in the application. New compiler optimizations will be developed to reduce the demands of power-critical computations. Further, the compiler will explicitly manage processor resources in a fine-grained manner to enable creating more power-effective hardware. This work will be explored in the context of the WIMS microcontroller, which provides a realistic and flexible environment to evaluate new compiler techniques. We expect the low-power software techniques that we develop will complement the hardware techniques developed by others to yield a substantive impact on the design of future low-power microprocessor systems.
Title:  Pseudo-nMOS Logic in Advanced SOI Processes
Graduate Students: Jayakumaran Sivagnaname (EECS) Funding Source: Semiconductor Research Corporation	Faculty Advisor: Richard B Brown (ECE-UT) Work Began: 01/01/2001
Project Goals:
Silicon-on-Insulator (SOI) technology can extend CMOS performance at small dimensions by reducing short-channel effects, minimizing source-drain capacitance, providing latchup immunity, and by yielding better soft-error rates. Pseudo-nMOS circuits have been traditionally used in critical paths to satisfy timing requirements at the expense of increased static power dissipation. However, at high clock frequencies, where the dynamic power component of static CMOS circuit becomes dominant, pseudo-nMOS circuits can be used due to their low dynamic power consumption. This project aims to optimize digital circuits by exploiting the inherent benefits of the SOI technology.
Title:  Resonant Clocking Using Parasitic Capacitance
Graduate Students: Alan J. Drake (EECS) Funding Source: IBM Austin Center for Advanced Studies	Faculty Advisor: Richard B Brown (ECE-UT) Work Began: 03/01/2001
Project Goals:
While power efficiency of succeeding process generations has improved, increased operating frequencies, integration levels, and leakage currents are taxing the power budgets of both high-performance and low-power VLSI designs. The 2000 Workshop on Intersection Types and Related Systems (ITRS) predicts today’s power dissipation to nearly double for both high-performance (from 90 to 170 watts) and low-power (from 1.4 to 2.6 watts) very-large-scale integrated (VLSI) designs by 2005. This increase in power dissipation is due mostly to clock distribution power scaling from both clock frequency and transistor integration levels. An additional power concern is that leakage currents, which are increasing due to technology scaling, are quickly increasing the static power as a percentage of total power. To continue scaling performance as in the recent past, power dissipation at all performance levels must be addressed. Improved circuit design is proposed in the ITRS as the most promising near-term solution for keeping power dissipation manageable. The road map also encourages exploring alternative technologies, such as Silicon-on-Insulator (SOI) technology. This work focuses on circuit and physical design approaches to leverage the low-power characteristics of partially depleted SOI technology to reduce both the clock and signal power in datapath circuits.
Title:  Micropower Digital SOI
Graduate Students: Robert M. Senger (EECS), Eric Marsman (EECS) Other Investigators: Scott A. Mahlke (EECS)	Faculty Advisor: Richard B Brown (ECE-UT) Work Began: 01/01/2001
Project Goals:
Power consumption of digital circuits has moved to the forefront as one of the most significant problems facing system designers. The power consumption problem can be subdivided into two key issues: power supply limitations and heat dissipation. As electronic devices become more portable, circuit designers must employ low-power techniques to achieve acceptable battery lifetimes. This project seeks to alleviate these problems by exploring low-power digital circuit design from several different angles. First, architectural and processing techniques will be analyzed from the power perspective. Second, low-power compiler and synthesis techniques will be explored in the context of the WIMS chip. We expect this multi-faceted approach will result in a general purpose, ultra-low-power microcontroller, surpassing what is commercially available.
Title:  Improving Energy Efficiency of Wide-Issue Microprocessors
Graduate Students: Junwei Zhou (ECE-MSU)	Faculty Advisor: Andrew J Mason (ECE-MSU) Work Began: 06/01/2004
Project Goals:
As processors continue to increase in issue width to exploit instruction-level and thread-level parallelism, processor power consumption has become a key design challenge. Distributing the hardware of microprocessors proves to be more energy efficient and scalable than a traditional centralized design [1, 2]. This project will analyze the design overhead of decentralized processor microarchitectures. New techniques will be developed to decrease the design overhead and improve the energy efficiency of microprocessors.
Title:  A Low-Power DSP Architecture for a Cochlear Implant System-on-a-Chip
Graduate Students: Eric Marsman (EECS)	Faculty Advisor: Richard B Brown (ECE-UT) Work Began: 09/01/2003
Project Goals:
This project is intended to develop and implement a digital core that executes the continuous interleaved sampling (CIS) algorithm for a cochlear implant (CI). Figure 1 shows a schematic diagram of the CIS algorithm. This core will be instituted as part of the WIMS microcontroller (see project description "Micropower Digital SOI") and explored as part of the system architecture for the cochlear prosthesis testbed. This architecture will have several programmable features in order to achieve the same variability for patient specific parameters as present day commercial implants. However, designing a custom architecture tuned specifically for this sound processing algorithm will be a lower power implementation than using a software programmable digital signal processing (DSP) chip as part of the system. Comparisons will be done to other existing implementations, including analog and MEMS filter bank versions.
Title:  MEMS-Based Energy Scavenging and Power Generation
Graduate Students: Tzeno V. Galchev (EECS) Post Doc: Haluk Kulah (EECS)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 06/01/2003
Project Goals:
Self-powered remote controlled microsystems are needed in many emerging applications such as environmental monitoring. The required power for these systems can be generated mainly in two ways: 1) by using electrochemical batteries and micro fuel cells, and 2) by energy scavenging from environmental sources such as ambient heat, light, and vibration. Although electrochemical batteries and microfuel cells can provide more power, they are not desirable for some applications due to chemicals and reactions involved during the generation process. Also, they have a limited life-time. A battery large enough to last the lifetime of the sensor would dominate the overall system size, and hence is not very attractive. As the sensor network increases in number and the device size decreases, the replacement of depleted batteries and fuel cells is not practical. Energy scavenging has become popular recently, because of clean power generation process and long life time. By scavenging energy, power can be generated from various environmental sources such as ambient heat, light, acoustic noise, and vibration. The ultimate goal of this project is to develop a MEMS-based multi-mode micro power generator that can harvest energy from different sources including heat, solar energy, and vibration. Such a generator can generate power with maximum efficiency regardless of the changes in the environmental factors.
Title:  Low Energy Capacitance to Digital Converter for Intraocular Pressure Sensor
Graduate Students: Yu-Shiang Lin (EECS) Other Investigators: David Blaauw (EECS)	Faculty Advisor: Dennis M Sylvester (EECS) Work Began: 09/01/2005
Project Goals:
This project is part of the intraocular pressure project that consists of a pressure sensor, capacitance-to-digital converter (CDC), microprocessor and battery. The goal is to have an integrated system that is able to be implanted in the eye. It is designed to be capable of measuring eye pressure continuously and record the results in SRAM. Two major constraints for the circuit are area and power. Since it has to be small enough for implantation purpose, the ideal dimension would be under 500μm by 500μm. Also, due to the small form factor for the battery, the lifetime is limited. In order to support an operating time of six months to one year, the average power consumption is targeted at 5nW. In this application, there is nearly no speed concern so that an appealing option is to trade speed for more power headroom. With its quadratic dependence on power consumption, decreasing Vdd is very effective to cut down dynamic power. Therefore, the circuit has to be operated in subthreshold region to meet the power requirement. Traditionally, CDCs have been implemented with complicated analog circuits that are hard to fit into our power budget. The proposed CDC structures are all digital designs and thus more suitable for subthreshold operating voltages. Several designs will be discussed and compared in the next sections.
Title:  Code Development for the Neural Prosthesis and the Environmental Monitoring Testbed
Graduate Students: David Ortiz Undergraduate Students: Eduardo J. Diaz (ECE-UPRM), Vanessa R. Vazquez (EECS-UPRM), Luis A. Calderon (ECE-UPRM), Manuel A. Ortiz (ECE-UPRM), Pedro J. Nieves, Omar A. Candelaria, Jaime Merced (ECE-UPRM), Alexander Toledo (ECE-UPRM), Mirayma V. Rodriguez, David J. Morales (ICOM), Debbie R. Ruperto, Henry Súcart, Harry Rosado, Maria M. Rodriguez-Mendez (ECE-UPRM), Marie Munoz (ECE-UPRM), Jose G. Santiago (ECE-UPRM)	Faculty Advisor: Nayda G. Santiago (ECE-UPRM) Work Began: 09/01/2005
Project Goals:
Our first goal is to complete the integration and development of the software for the Environmental Monitoring Testbed (EMT) in order to provide the WIMS ERC with a completely integrated system for the micro-gas chromatograph. Our second goal is the development and specification of the code for a cochlear implant for the Neural Prosthesis Testbed (NPT).
Title:  An Integrated Microsystem for Environmental Sensing Powered by Energy Scavenging
Graduate Students: Supriya Kher (EE-PVAMU), Marcus Golston (EE-PVAMU), Felicia J. Lindor (EE-PVAMU), Miguel F. Ribeiro (EE-PVAMU), Crystal Robinson (EE-PVAMU), Richard Tate (EE-PVAMU) Undergraduate Students: Henry Babb (EE-PVAMU), Jon-Paul A. Dixon (EE-PVAMU), Xavier Godoy (EE-PVAMU), Shirnette Y. Hunter (EE-PVAMU), Erick Jackson (EE-PVAMU), Pamela McKnight (EE-PVAMU), David L. McQuiller II (EE-PVAMU), Preston Perry (EE-PVAMU), DeAundre Ray (EE-PVAMU), Marc Robey (EE-PVAMU), Clayce Singletary (EE-PVAMU) Other Investigators: James A. Northern (EE-PVAMU)	Faculty Advisor: Pamela Holland Obiomon (EE-PVAMU) Work Began: 01/01/2004
Project Goals:
There is strong interest in developing very small integrated microsystems capable of precision measurements of environmental and biomedical parameters and yet able to operate by scavenging energy from their surroundings. Power levels of less than 50μW will be needed in many such systems. Measuring environmental temperature, pressure, and humidity using a battery at night trickle charged by solar energy during the day or measuring blood pressure using kinetic energy derived from the beating heart are possible examples. In realizing such microsystems, sensors, readout and control electronics, a suitable power source, and some means of storing the information and/or reporting it to the outside world will be needed. This project seeks to demonstrate such microsystems, defining their limits and trade-offs in terms of power, size, accuracy, and speed.
Title:  A Dynamic Reconfigurable Micropower A/D Converter for Multi-Channel Biomedical Sensor Interface
Graduate Students: Cheong Kun (ECE-MSU), Jichun Zhang (ECE-MSU) Funding Source: Siemens Corporation	Faculty Advisor: Andrew J Mason (ECE-MSU) Work Began: 01/15/2003
Project Goals:
Wireless Implantable Microsystems with high-density sensoring probes require local micropower A/D conversion that has multi-channel capability and resolution/speed reconfigurability [1]. This project seeks to develop a structural dynamically reconfigurable A/D converter to meet the requirements.
Title:  Multi-Mode Energy Scavenging From the Environment
Graduate Students: Tzeno V. Galchev (EECS) Funding Source: Other Sources	Faculty Advisor: Khalil Najafi (EECS) Work Began: 05/01/2005
Project Goals:
Self-powered remote microsystems and sensor networks are needed in many emerging applications such as environmental monitoring. The required power for these systems can be generated mainly in two ways: 1) by using electrochemical batteries and micro fuel cells and 2) by energy scavenging from environmental sources such as ambient heat, light, and vibration. Although electrochemical batteries and microfuel cells can provide more power, they are not desirable for some applications due to their limited lifetime, and size. A battery large enough to last the lifetime of the sensor would dominate the overall system size, and hence is not very attractive. As the sensor network increases in number and the device size decreases, the replacement of depleted batteries and fuel cells is not practical. Energy scavenging has become popular recently, because of clean power generation process and long lifetime. By scavenging energy, power can be generated from various environmental sources such as ambient heat, light, acoustic noise, vibration, and ambient RF signals. The ultimate goal of this project is to develop a MEMS-based multi-mode micro power generator that can harvest energy from different sources including heat, solar energy, and vibration. Such a generator can generate power with high efficiency regardless of the changes in environmental factors.
Title:  Chip to Chip Proximity Communication
Graduate Students: Yu-Shiang Lin (EECS) Other Investigators: David Blaauw (EECS)	Faculty Advisor: Dennis M Sylvester (EECS) Work Began: 07/01/2005
Project Goals:
Implement low power chip to chip communication through capacitive coupling. Modern VLSI design benefits from the fact that physical dimensions keep shrinking, thus gaining performance and reducing power as well. However, the energy dissipated by chip to chip communication does not scale because of physical constraints on bonding pads and ESD. The idea of using capacitive coupling to eliminate the ESD component has been proposed for years. However, it is yet to overcome the difficulty of aligning pads properly without the help of accurate mechines. Our goal is to design a chip to chip communication mechanism that is able to transmit subthreshold signal without alignment issues.
Title:  Robust SRAM Design for Subthreshold Operation
Graduate Students: Bo Zhai (EECS) Other Investigators: Dennis M. Sylvester (EECS)	Faculty Advisor: David Blaauw (EECS) Work Began: 01/01/2005
Project Goals:
To develop new design styles for static memories that can operate at subthreshold operating voltages.
Title:  Low Power Digital Circuit Design
	Work Began: 01/01/2003
Project Goals:
The rapid scaling of process technologies has led to greatly improved performance at the cost of increased power consumption, most prominently leakage power. The sub-threshold conduction current increases by 3-5X in each technology generation due to scaling of the threshold voltage (VTH) while the gate tunneling current increases by 2.5X for every 1 Å decrease in oxide thickness, resulting in a nearly 30X increase in gate tunneling current per technology generation. Such large increases in leakage current have resulted in leakage power estimates of more than 40% of the total power budget for designs in the 90nm generation and beyond. New techniques will be developed to combat this leakage power.
Title:  Design and Implementation of Low-Power DMA and Dynamic Voltage and Frequency Scaling Architectures for the WIMS Microcontroller System-on-a-Chip
Graduate Students: Nathaniel C. Gaskin (ECE-UT)	Faculty Advisor: Richard B Brown (ECE-UT) Work Began: 09/01/2005
Project Goals:
Our primary objective is to dramatically reduce the power consumption of the WIMS microcontroller. The implementation of direct memory access (DMA) in the WIMS microcontroller to enhance data transfer between memory and the loop cache will allow for this reduction. Dedicated DMA instructions are needed to fill the loop cache quickly without incurring the overhead of multiple load-store instructions. These instructions will allow a compiler-managed dynamic loop-cache filling algorithm to control fast, low-power transfer of an entire register window upon branches to or from subroutines and interrupt handlers. Overall power requirements can thereby be reduced, further enhancing the performance and utility of the microcontroller. In addition to DMA, a low-power standard cell library will be designed and synthesized for several power-hungry blocks of the microcontroller in order to further decrease power requirements during heavy computation in the DSP core. Clock gating will be used to reduce the leakage current during no-operation of a block (power save mode). Our implemenation of a dynamic voltage and frequency scaling (DVFS) architecture will also reduce power consumption in the WIMS microcontroller. Instructions will allow the user to regulate the operating voltage and frequency to change with the activity of the program. This will give the microcontroller the ability to be as efficient as possible during non compute-intensive activities.
Title:  Design and Implementation of Low-Power DMA Architecture for a Cochlear Implant System-on-a-Chip
Graduate Students: Nathaniel C. Gaskin (ECE-UT), Spencer S. Kellis (ECE-UT), Amlan Ghosh (ECE-UT)	Faculty Advisor: Richard B Brown (ECE-UT) Work Began: 09/01/2005
Project Goals:
Our primary objective is to implement direct memory access (DMA) in the WIMS microcontroller to enhance data transfer between memory and the loop cache. Dedicated DMA instructions are needed to fill the loop cache quickly without incurring the overhead of multiple load-store instructions. These instructions will allow a compiler-managed dynamic loop-cache filling algorithm to control fast, low-power transfer of an entire register window upon branches to or from subroutines and interrupt handlers. Overall power requirements can thereby be reduced, further enhancing the performance and longevity of the microcontroller. In addition to DMA, a low-power standard cell library will be designed and synthesized for several power-hungry blocks of the microcontroller in order to further decrease power requirements during heavy computation in the DSP core. Clock gating will be used to reduce the leakage current during no-operation of a block (power save mode).
Title:  Nanosim Power Analysis of the WIMS Microcontroller
Graduate Students: Spencer S. Kellis (ECE-UT) Funding Source: ERC/IBM	Faculty Advisor: Richard B Brown (ECE-UT) Work Began: 10/01/2005
Project Goals:
This project will build on existing hardware methodologies for obtaining accurate Energy Per Instruction (EPI) measurements to provide simulated EPI measurements using Nanosim. WIMS microcontroller (MCU) research has already resulted in EPI data which has been utilized in designing a power-aware C-compiler. The results of these simulations will collaborate with previous hardware results to create a robust power model for the chip.
Title:  TEST
Funding Source: WIMS	Work Began: 03/23/2005
Title:  Robust Clock Tree Synthesis
Graduate Students: Matthew R. Guthaus (EECS)	Faculty Advisors: Work Began: 04/01/2005
Project Goals:
Integrated circuit performance is largely determined by the efficiency and quality of synchronous clock distribution. A poor clock distribution can consume an inordinate amount of power, limit circuit performance or prevent correct functionality at all speeds. Many other works have presented algorithms to minimize the nominal, deterministic skew of a clock tree during physical design, but the authors only consider that the delay to balance is a nominal value. Process variability of clock delay elements such as interconnect height, width, and spacing; and buffer drive strength can have a significant impact on skew in what is called process induced skew. This work aims to generate clock trees that are robust in the presence of process variation without using high-powered clock grids and redundant cross-links.
Micropackaging, Microfabrication, and Power Source Technologies
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Title:  A Wafer-Level Vacuum Package with Vertical Feedthroughs
Graduate Students: Junseok Chae (EECS) Funding Source: DARPA, WIMS ERC Post Doc: Junseok Chae (EECS)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 03/01/2003
Project Goals:
Low-cost vacuum packaging of MEMS has become one of the most important challenges in the MEMS industry for a number of emerging applications such as resonant sensors and RF MEMS. There are many requirements to satisfy for a MEMS package including small size, vacuum/hermetic capability, feedthroughs, wafer-level processing, and low cost. Among them, feedthroughs, usually lateral, pose several challenges for MEMS packages. They use valuable die area, are often the source of failure/leakage, and complicate cavity sealing due to added process steps or non-planar surfaces. This project seeks to develop a micromachined vacuum package with vertical feedthroughs, and demonstrate long-term vacuum capability of micropackages using integrated Pirani gauges.
Title:  Thin-Film Materials for Microsystem Technologies by Cathodic Vacuum Arc Deposition
Graduate Students: Hui Xia (MSE-MTU) Funding Source: MTU	Faculty Advisor: Paul L Bergstrom (ECE-MTU) Work Began: 08/20/2002
Project Goals:
This project investigates the use of pulsed cathodic vacuum arc deposition technique to prepare thin-film materials for MEMS applications. The specific goals are to produce silicon-based thin films at low temperature compatible with CMOS fabrication (<400°C) using a pulsed cathodic vacuum arc deposition system. This technique and material development can enable the integration of microsystem devices with microelectronic processes in a CMOS-first process flow.
Title:  Low-Temperature Microsystem Technologies by PECVD
Graduate Students: Jianlin Liang (ECE-MTU) Funding Source: MTU	Faculty Advisor: Paul L Bergstrom (ECE-MTU) Work Began: 09/01/2002
Project Goals:
This project explores the development of MEMS and microsystem devices through low-temperature thin-film deposition techniques. The specific goals are to produce MEMS device quality materials with desirable properties compatible with other mainstream microelectronic and microsystem process technologies. This material development would lead to integrating microsystem devices with microelectronic processes in a CMOS-first process flow [1-3].
Title:  Localized Annealing of Polysilicon Microstructures by Inductively Heated Ferromagnetic Films
Graduate Students: Melissa L. Trombley (ECE-MTU) Funding Source: U.S. Dept. of Defense Other Investigators: Craig R. Friedrich (ME-MTU)	Faculty Advisor: Paul L Bergstrom (ECE-MTU) Work Began: 09/01/2001
Project Goals:
This project is exploring the formation of microsystem technologies, integrated with high-density CMOS technologies, by combining localized high-temperature annealing of MEMS and other microsystem materials and low-temperature deposition processing for microsystem structural materials, allowing post-CMOS integration of these technologies.
Title:  Micro Electro-Discharge Machining (μEDM) for MEMS Applications
Graduate Students: Ken'ichi Takahata (EECS) Funding Source: NSF/UM	Faculty Advisor: Yogesh B Gianchandani (EECS) Work Began: 06/01/2000
Project Goals:
This project aims to increase throughput as well as machining precision in the μEDM process. The goal is to extend the application fields in MEMS by exploiting the exceptional capability of μEDM, which can micromachine any electrically conductive materials.
Title:  Poly-C RF MEMS Resonators
Graduate Students: Nelson Sepulveda-Alancastro (ECE-MSU), Jing Lu (ECE-MSU)	Faculty Advisor: Dean M Aslam (ECE-MSU) Work Began: 09/01/2000
Project Goals:
The goals of this project are (a) to study fabrication technology of polycrystalline diamond (poly-C) films for MEMS resonators for the wireless interfaces; (b) to design, fabricate, and test the poly-C RF MEMS resonators for wireless interfaces; and (c) to study the energy dissipation mechanisms in poly-C resonators and find its relationship with film microstructure.
Title:  Vibration Isolation and Shock Protection Technologies For MEMS
Graduate Students: Sang Won Yoon (EECS) Funding Source: DARPA-HERMIT Post Doc: Sang Woo Lee (EECS) Other Investigators: Noel C. Perkins (ME)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 01/01/2004
Project Goals:
The environment has a profound impact on the performance and the reliability of micromachined instruments. Especially as performance levels are increased, the need for protection against environmental conditions becomes more pronounced. One major environmental condition is external mechanical disturbances such as vibration and incident shock. These disturbances induce long-term undesirable effects that are uncorrectable with electronics, and cause permanent damage to the device structure due to high shock. To protect the MEMS device from these unwanted effects, it is important to isolate it from mechanical vibrations and shocks. This project seeks to develop generic micro packaging technologies that provide mechanical isolation and protect against severe shock for microsystems and microinstruments such as inertial sensors and resonators.
Title:  All-Diamond Packaging for WIMS
Graduate Students: Xiangwei Zhu (ECE-MSU) Other Investigators: Khalil Najafi (EECS)	Faculty Advisor: Dean M Aslam (ECE-MSU) Work Began: 09/01/2001
Project Goals:
This project's goals are to develop an all-diamond packaging technology where the material for both the packaging and the interconnects is poly-C (Figure 1) and to build and test all-diamond packaging for WIMS.
Title:  A Micromachined DC-to-DC Boost Converter for Powering High-Voltage Microsensors
Graduate Students: Kabir Udeshi (ME)	Faculty Advisor: Yogesh B Gianchandani (EECS) Work Began: 09/01/2002
Project Goals:
The goal of this project is to create a component that will provide high voltages that are required by other WIMS components in the environmental monitoring testbed, such as the radiation detector in a small footprint. This will be accomplished by creating a high-efficiency (>85%), scalable, micromechanical DC-to-DC converter that will be supplied with 3-10V and output 300V at 1W. The target area is less than 1cm2.
Title:  Scaling and Process Integration Challenges in Micro-EDM Technology
Graduate Students: Mark T. Richardson (EECS) Funding Source: Sandia National Laboratories/UM	Faculty Advisor: Yogesh B Gianchandani (EECS) Work Began: 06/01/2004
Project Goals:
The goals of this project are to study the effects of high density µEDM batch machining on precision and throughput and to refine process integration between µEDM and the LIGA process. This will lead to direct improvements in batch mode µEDM machining for devices such as cardiovascular stents [1] and DC-to-DC boost converters [2].
Title:  Hermetic Packaging and Bonding Technologies for WIMS
Graduate Students: Timothy J. Harpster (EECS)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 09/01/1998
Project Goals:
Hermetic packaging is critically needed in many emerging micromachined sensors and actuators. This project will study and develop new wafer-level packaging technologies that utilize shells and capsules to provide a truly hermetic environment. Wafer bonding is one of the basic technologies used to form a hermetic package and will be studied and explored in developing both glass-Si and Si-Si packages. Although many bonding techniques have been developed, the need still exists for new technologies that will allow wafers of different materials to be bonded at low temperatures providing packages for both hermetic and vacuum encapsulation of microsystems. There is an equally important need to provide feedthroughs from the encapsulated device to external sensors without compromising package hermeticity. Appropriate feedthrough topologies will be adapted to the bonding method.
Title:  Gold-Silicon Eutectic Wafer Bonding Technology for Vacuum Packaging
Graduate Students: Jay S. Mitchell (ME) Other Investigators: Gholamhassan R. Lahiji (WIMS)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 09/01/2000
Project Goals:
Low-cost, simple, and reproducible hermetic/vacuum packaging technologies are required for many microsystems, including resonant devices and RF MEMS. Several groups, including ours, are developing new techniques for implementing small packages [1-4]. Most of these involve bonding of two wafers, a package (cap) silicon/glass wafer, and a device silicon wafer. Several wafer bonding techniques, including adhesive, glass frit, solder, eutectic, silicon fusion/direct and anodic bonding have been used. Of these, eutectic bonding is one of the most attractive because it is easy to use, it forms a soft eutectic to allow bonding over non-planar surfaces and it can be done at slightly above the eutectic temperature (363°C). Although Au-Si eutectic has long been used for wafer bonding and packaging [1], few have reported its successful use in vacuum packaging. There are several reasons for this, including non-uniform eutectic flow, void formation, insufficient eutectic material in between wafers causing non-uniform bonding, oxidation of bond surfaces, and poor surface contact/adhesion. Furthermore, few published reports have presented data showing full wafer-level bonding [1]. This project aims at developing a uniform, high-yield, reproducible, silicon-gold eutectic wafer-level bonding technology used for vacuum encapsulation of MEMS.
Title:  Modular Assembly and Packaging of Multi-Substrate Microsystems (WIMS Cube)
Graduate Students: Asli B. Ucok (EECS) Other Investigators: Joseph M. Giachino (EECS)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 09/01/2000
Project Goals:
Miniature microsystems require that electrical signals be transferred between several substrates in a small volume with high fidelity and performance. In case of fluidic systems, leak-proof connections between the subsystems also play an important role. While several different multi-chip module technologies have been developed in the past, none provide the flexibility, modularity, and small size needed in the environmental monitor testbed. This project will develop a novel connector for electrical and fluidic connections that allows the assembly and packaging of substrates containing circuits, sensors, and actuators in a removable, modular approach. Issues such as fatigue, contact resistance, flow resistance, size versus mechanical compliance, and actuation of the connectors for assembly will be studied. Standard interface protocols will be developed in conjunction with other projects in the ERC to ensure that all substrates conform to the same size and interconnection schemes to guarantee that the final system can be assembled and packaged in a modular fashion.
Title:  An Actively Controlled Microvalve for Distributed Cooling
Graduate Students: Jong M. Park (EECS), Allan T. Evans (EECS) Funding Source: NASA Other Investigators: Gregory Nellis (ME-UW-Madison), Sanford Klein (ME-UW-Madison), Pat Roach (NASA-Ames Research Center)	Faculty Advisor: Yogesh B Gianchandani (EECS) Work Began: 01/01/2005
Project Goals:
The goal of this project is to create a micromachined actively controlled valve that is capable of operating reliably at very low temperatures (≈ 20K), and provides large flow area variation. Such a valve will be used on future NASA missions that require cooling of large optical structures, instrument chambers, and propellant storages with high degree of temperature stability and small temperature gradients.
Title:  Vacuum and Hermetic Packaging of MEMS Using Solder
Graduate Students: Warren (Neil) C. Welch (EECS) Funding Source: DARPA	Faculty Advisor: Khalil Najafi (EECS) Work Began: 10/01/2002
Project Goals:
This project seeks to develop vacuum and hermetic packaging and wafer bonding technologies using a variety of solder materials. Packaging continues to pose a major challenge to the successful commercialization of MEMS and Microsystems in many application areas. One of these application areas is RF MEMS, where micro-machined resonators, switches, and passive components are used to implement high-performance wireless communication systems. Many of these MEMS devices need to be packaged either in vacuum or in a hermetic environment. The packaging itself needs to be performed at the wafer level, using a low-temperature process, occupy very little die area and provide long-term stability and reliability. Although several techniques and materials have been used for implementing these vacuum/hermetic packages, little work has been done with solder as a wafer bonding material for packaging MEMS. Solder provides several advantages, including low-temperature processing, and compatibility with standard IC processes. This project will develop low-temperature metal bonding processes that provide wafer-level hermetic packaging for RF MEMS.
Title:  Microscale Convective Flows Driven by Non-Contact Micromachined Heat Sources
Funding Source: Whitaker Foundation, University of Michigan	Work Began: 08/01/2004
Title:  A Micromachined Sputter Ion Pump for Cavity Environment Control
Graduate Students: Scott A. Wright (EECS) Funding Source: NSF Grant	Faculty Advisor: Yogesh B Gianchandani (EECS) Work Began: 06/01/2005
Project Goals:
This project is developing the ability to control pressure, humidity and the composition of gases inside of a micropackage after the package has been sealed. Sputter ion pumps have been used on a large scale for high vacuum applications but have traditionally been used to pump air out of a chamber [1, 2]. This project uses sputtered metals inside a sealed cavity which bond to gases in the air. These new molecules fall to the substrate surface, thus removing air and lowering the pressure without pumping the air out of the cavity. While getters have been used to reduce the amount of air in a sealed cavity, they require heating in order to function and do not allow the user to control the amount of air removed after the package has been sealed [3]. This micropackaging technique allows the user to control the pressure and humidity in a micropackage, as well as remove gases at different rates.
Title:  Ultrasonically and Electro-Discharge Micromachined Biopsy Tool
Graduate Students: Tao Li (EECS) Other Investigators: Roma Y. Gianchandani (UM-Internal Medicine)	Faculty Advisor: Yogesh B Gianchandani (EECS) Work Began: 06/01/2003
Project Goals:
This project aims to create a micromachined biopsy tool with integrated sensors to provide realtime guidance for the medical procedure of fine needle aspiration (FNA) biopsy. To process bulk PZT material, this project also involves the development of batch mode ultrasonic micromachining process which can achieve transfer of lithographic patterns onto hard, brittle and nonconductive materials such as ceramics (including PZT) and glass.
Title:  Low-Power Thermal Isolation for Environment-Resistant Microinstruments
Graduate Students: Sang-Hyun Lee (EECS), Andrew Kuo (EECS) Funding Source: DARPA Post Doc: Sang Woo Lee (EECS)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 01/01/2004
Project Goals:
The environment has a profound impact on the performance of precision micromachined instruments increasingly needed in many applications. To realize the potential of MEMS, it is critical that the environment, especially temperature, around the instrument be controlled. External temperature can easily corrupt the output of an instrument, and can induce long-term undesirable effects that are not easily correctable using electronics. An effective approach to overcome this temperature sensitivity is to control/maintain the temperature around the microinstrument using a micro-oven. This project seeks to develop a new thermal isolation package, and a generic assembly approach for instrument-platform integration, as well as low-power and precise temperature control circuitry and electronics.
Title:  Ultracompliant Thermal Probes for High Throughput Thermal Imaging, Patterning, and Fluidic Actuation
Graduate Students: Amar S. Basu (EECS) Funding Source: SRC, DARPA, Whitaker Foundation, University of Michigan	Faculty Advisor: Yogesh B Gianchandani (EECS) Work Began: 09/01/1997
Project Goals:
This project explores the use of microfabricated thermal probes and thermal probe arrays for 1) micro-scale manipulation of fluids, 2) high throughput, high resolution thermal imaging, and 3) thermal patterning of thin films.
Title:  FIB-Patterned Single Electron Transistors and Nanoporous Materials Development
Graduate Students: P. Santosh K. Karre (ECE-MTU) Funding Source: DARPA MTO / ARL Other Investigators: Craig R. Friedrich (ME-MTU)	Faculty Advisor: Paul L Bergstrom (ECE-MTU) Work Began: 09/01/2003
Project Goals:
The research will produce a focused-ion beam (FIB) based process flow for room temperature single-electron transistor (SET) device development and will assess the impact of FIB-etch and deposition capabilities on the structures that are formed. A detailed fabrication process flow will be documented, and the formation of a SET device by focused ion beam processing will be demonstrated. Nanoporous materials for nanosensor applications will result in a proposed FIB-based process to produce test samples for a 7 to 30nm diameter vertical pore in silicon material. The research will also demonstrate structured high-aspect-ratio vertical pores in silicon to study the vapor pressure relationship below 30nm diameters and compare to theory.
Title:  Silicon Carbide MEMS Technologies
Graduate Students: Nupur Basak (EE-HU), Aaron Jackson (EE-HU) Undergraduate Students: Richard Castillo (EE-HU), Idaliz R. Dátil (EE-HU), Janessa Smith (EE-HU) Post Doc: Juan C. White (EE-HU)	Faculty Advisor: Gary L. Harris (EE-HU) Work Began: 08/01/2004
Project Goals:
This project is exploring the development of silicon carbide (SiC) MEMS in sensors and actuators intended for use in microsystems. The goals are to produce SiC MEMS materials with electrical, optical, and mechanical properties that will enhance and expand the capabilities of mainstream silicon structures and to demonstrate a SiC testbed for MEMS intended for use under extreme environmental conditions.
Title:  Micromachined Joule-Thomson Cryosurgery Probe
Graduate Students: Weibin Zhu (EECS) Funding Source: NIH Other Investigators: Michael Frank (ME-UW-Madison), Gregory Nellis (ME-UW-Madison), Sanford Klein (ME-UW-Madison)	Faculty Advisor: Yogesh B Gianchandani (EECS) Work Began: 07/01/2003
Project Goals:
The goal of this project is to create a miniature micromachined cryosurgical probe based on silicon micromachined technology that can reach temperature 150K with at least 20W cooling power.
Title:  Development of a GaAs/GaAlAs Prosthetic Retina
Graduate Students: O'tega Ejofodomi (EE-HU), Alexis Boateng (Biology-HU), Ewart S. Orr (EE-HU) Post Doc: James Griffin (EE-HU) Other Investigators: Winston Anderson (Biology-HU)	Faculty Advisor: Gary L. Harris (EE-HU) Work Began: 06/01/2004
Project Goals:
The goal of this project is to explore the development of a implanted GaAs/GaAlAs prosthetic retina for human applications. Research previously performed has encouraged the possibility that a silicon solar cell may serve as the basis for visual prosthesis for patients who suffer from age-related macular degeneration (AMD) and retinitis pigmentosa (RP). Aluminum gallium arsenide (AlGaAs) /gallium arsenide (GaAs) is being investigated to develop a stimulating array of solar cells that can be customized to function as a retinal prosthesis device with main improved efficiency over silicon like devices.
Title:  Poly-C Micro and Nano Resonators
Graduate Students: Jing Lu (ECE-MSU)	Faculty Advisor: Dean M Aslam (ECE-MSU) Work Began: 01/01/2006
Project Goals:
The goals of this project are to (a) design, fabricate, and test poly-C micro and nano resonators for sensors and wireless interfaces; (b) improve quality factor and output impedance using novel resonator devices.
Environmental Sensors & Subsystems
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Title:  A Low-Power Pressure-Programmed Separation System for a µGC
Graduate Students: Joseph A. Potkay (EECS) Other Investigators: Richard D. Sacks (CHEM), Edward T. Zellers (EHS), Massoud Kaviany (ME)	Faculty Advisor: Kensall David Wise (EECS) Work Began: 09/01/2000
Project Goals:
Accurate chemical (gas) sensing is critically needed for a wide variety of applications, including those in industrial process control, environmental monitoring, and homeland security. However, past devices have often lacked speed, sensitivity, stability, and (especially) selectivity. This project seeks to develop a high-performance pressure-programmed separation column for a 1cc micropower gas chromatography (μGC) system capable of analyzing a wide variety of gaseous mixtures in seconds with high selectivity and part-per-billion sensitivity.
Title:   Growth of Conformal CNT Adsorbent Layers for a Micro GC and Sensors
Graduate Students: Ming Gu (ECE-MSU) Other Investigators: Edward T. Zellers (EHS)	Faculty Advisor: Dean M Aslam (ECE-MSU) Work Began: 01/01/2006
Project Goals:
This project seeks to develop a technology for conformal deposition of high-density carbon nanotubes (CNTs) as adsorbent materials in the (thermally desorbed) vapor micropreconcentrator/ focuser (µPCF) module of the WIMS micro gas chromatograph (µGC). The work investigates the effect of synthetic conditions on CNTs adsorption and desorption properties and optimizing their performance.
Title:  A Micromachined WIMS Vacuum Pump
Graduate Students: Hanseup S. Kim (EECS), Aaron A. Astle (AERO) Other Investigators: Luis P. Bernal (AERO), Peter D. Washabaugh (AERO)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 01/01/2001
Project Goals:
An efficient, high-flow, high-pressure, low-power, and small vacuum micropump is needed in many emerging microsystem applications, such as gas analysis using a micromachined gas chromatograph (µGC). Especially the WIMS µGC needs a pump that supports the two different operation modes of the µGC: sampling and analysis. However, previous gas micropumps have shown only limited capabilities, such as low flow-rate, low pressure, and large volume, thus failing to meet the requirements of the WIMS µGC. Therefore, the goals of this research are: 1) to develop a high-performance vacuum micro pump overcoming the limitations of previous micropumps and 2) to demonstrate its operation in the WIMS environmental monitoring testbed.
Title:  A Temperature-Programmed Low-Power Separation Column for a µGC
Graduate Students: Masoud Agah (EECS) Other Investigators: Richard D. Sacks (CHEM), Massoud Kaviany (ME), Edward T. Zellers (EHS)	Faculty Advisor: Kensall David Wise (EECS) Work Began: 06/01/2001
Project Goals:
Accurate chemical (gas) sensing is critically needed for a wide variety of applications, including those in industrial process control, environmental monitoring, and homeland security. However, past devices have often lacked speed, sensitivity, stability, and (especially) selectivity. This project seeks to develop a high-performance separation column for a 1cc micropower gas chromatography (µGC ) system capable of analyzing a wide variety of gaseous mixtures in seconds with high selectivity and part-per-billion sensitivity.
Title:  Actuator Design and Simulation for a µGC Vacuum Pump
Graduate Students: Aaron A. Astle (AERO) Other Investigators: Peter D. Washabaugh (AERO), Khalil Najafi (EECS)	Faculty Advisor: Luis P Bernal (AERO) Work Began: 09/01/2000
Project Goals:
This project sought to develop innovative design concepts and modeling tools for the μGC vacuum pump that requires high pumping performance within the strict size and power consumption constrains of the testbed. Past micro vacuum pump designs do not meet these requirements. Engineering and CFD models have been developed, validated, and used to determine the performance of innovative new pump designs in collaboration with the μGC vacuum pump development effort. The μGC vacuum pump is targeted at creating a 0.5atm pressure differential at low flow rates or 25sccm flow rate at low pressure differentials (typical values).
Title:  Porous Silicon Technology for a Micro Gas Chromatograph (μGC)
Graduate Students: Jin Zheng (ECE-MTU) Other Investigators: Kensall D. Wise (EECS), Edward T. Zellers (EHS)	Faculty Advisor: Paul L Bergstrom (ECE-MTU) Work Began: 01/01/2002
Project Goals:
In a micro gas chromatograph (μGC), the inlet particulate filter and the on-board calibration standard are indispensable components. By removing moisture and particles, the inlet particulate filter helps to extend the lifetime of the system. While a diffusion vapor source contributes to the system's performance by collecting diagnostic information to compensate for instrument drift, aging, malfunction, or environmental factors. This project seeks to develop porous silicon materials and relevant assembling and packaging methods for inlet particulate filter and on-board calibration standard. These activities will progress in collaboration with researchers at the University of Michigan.
Title:  Testing and Evaluation of Microfabricated Columns
Graduate Students: Shaelah M. Reidy (CHEM), Gordon R. Lambertus (CHEM) Other Investigators: Edward T. Zellers (EHS), Kensall D. Wise (EECS)	Faculty Advisor: Richard D Sacks (CHEM) Work Began: 11/01/2001
Project Goals:
This project explores the use of independent temperature programming of a tandem microfabricated column ensemble to tune separations of complex vapor mixtures using integrated heaters and temperature sensors. Static coating of the micro-column stationary phases to achieve uniform, thin-wall coatings is also being explored to maximize resolution.
Title:  Optimization of Micromachined GC Columns
Graduate Students: Gordon R. Lambertus (CHEM), Shaelah M. Reidy (CHEM), Cory S. Fix (CHEM), Joseph A. Potkay (EECS) Other Investigators: Kensall D. Wise (EECS)	Faculty Advisor: Richard D Sacks (CHEM) Work Began: 09/01/2001
Project Goals:
This project explores critical factors related to the optimization of microfabricated gas chromatographic columns for separating complex vapor mixtures at high speed, including dual-column pressure-tuning strategies, stationary-phase deposition methods, and interfacing with miniaturized spectrometric detectors.
Title:  A Power-Efficient, Integrated Preconcentrator-Focuser for a µGC
Graduate Students: Helena K. Chan (EECS) Funding Source: Sandia National Laboratories Fellowship Other Investigators: Edward T. Zellers (EHS)	Faculty Advisors: Work Began: 09/01/2000
Project Goals:
The microfabricated preconcentrator-focuser (μPCF) is the front-end analytical component in the WIMS μGC which preconcentrates parts-per-billion (ppb) concentrations of volatile organic compounds (VOCs) from ambient air and subsequently injects them onto the μGC columns for separation. Preconcentration and sample injection are of intense interest to the GC community because the high separation efficiency of microscale diameter columns can only be realised with appropriately sized samples at the inlet typically on the order of 10's of μL. In addition, detection of trace-level compounds using chemiresistor arrays makes preconcentration a necessity. The goal of this project is to demonstrate the unique advantages offered by the microscale via Si micromachining: low-dead volume and rapid heating with integrated heating elements for efficient heat transfer to the adsorbents. Packaging and integration goals include modularity and environmental robustness for reliable integration into a common microfluidic/electrical μGC substrate.
Title:  Artificial Neural Networks for a Multi-Sensor Micro-GC Detector
Graduate Students: Chunguang Jin (EHS), Qiongyan (Judy) Zhong (EHS)	Faculty Advisor: Edward T Zellers (EHS) Work Began: 09/01/2001
Project Goals:
This project seeks to develop multivariate chemometric methods to address critical modeling and data analysis functions needed to guide the development and allow the implementation of the WIMS micro-GC. Methods will be developed for combining these sophisticated neural-net and statistical methods with physicochemical models for the purpose of vapor recognition and quantification.
Title:  Test Structures for Controlled Vapor Generation
Graduate Students: Kate S. Hunt (CHEM), Jin Zheng (ECE-MTU) Other Investigators: Paul L. Bergstrom (ECE-MTU)	Faculty Advisor: Edward T Zellers (EHS) Work Began: 09/01/2000
Project Goals:
This project concerns developing an integrated, passive calibration-vapor source for the WIMS μGC. The current design consists of a 3-layer structure with a porous silicon micromachined reservoir, a bonded Pyrex spacer, and a bonded DRIE diffusion channel that will connect to the μGC system inlet channel (Figure 1). It will provide a means for collecting diagnostic information to compensate for instrument drift, aging, malfunction, or environmental factors. The device will be situated between the sample inlet and the preconcentrator of the μGC, and will be operated at ambient temperature either in a continuous-generation mode or controlled by an integrated two-way on/off diaphragm valve. Considerations of the system operational criteria have led to choosing n-decane as the internal standard for the μGC. The source will produce ppb level calibration standards over a wide range of system operating temperatures.
Title:  Designed Materials for an Integrated Vapor Preconcentrator
Graduate Students: Rebecca Veeneman (CHEM), Kate S. Hunt (CHEM), Qiongyan (Judy) Zhong (EHS) Other Investigators: Stella W. Pang (EECS), Dean M. Aslam (ECE-MSU), Adam J. Matzger (CHEM)	Faculty Advisor: Edward T Zellers (EHS) Work Began: 09/01/2000
Project Goals:
This project seeks to develop and characterize high-surface-area adsorbent materials for use in the (thermally desorbed) vapor micro-preconcentrator-focuser (μPCF) module of the WIMS μGC. Initial research optimized the nature and quantities of known, carbon-based adsorbent materials for use in a multi-adsorbent bed to provide sufficient capacity and efficient, sharp desorption of trapped vapors [1-2]. On-going work concerns modeling these materials to predict performance parameters, testing them for capturing markers of environmental tobacco smoke (ETS), and testing the μPCF performance against system specifications. The use of novel, high-surface-area nanocomposite materials that offer greater control of adsorption properties and improved processability is also being explored.
Title:  A Microsensor Array Employing Metal Nanoclusters
Graduate Students: William H. Steinecker (CHEM), Christopher W. Avery (CHEM) Undergraduate Students: Patrick J. Quinn (EECS), Alex Saenz (EECS) Other Investigators: Cagliyan Kurdak (PHYS)	Faculty Advisor: Edward T Zellers (EHS) Work Began: 09/01/2000
Project Goals:
This project concerns developing a highly sensitive, integrated chemiresistor (CR) array for the WIMS micro gas chromatograph (μGC) detector to enable the determination of complex volatile organic compound (VOC) mixtures at trace levels. The work addresses the need for an ultra-small, low-power, universal VOC detector capable of vapor recognition.
Title:  The MicroGeiger: A Beta Particle Radiation Detector
Graduate Students: Christine K. Eun (EECS), Tze-Ching Fung (EECS) Other Investigators: Ranjit Gharpurey (EECS)	Faculty Advisor: Yogesh B Gianchandani (EECS) Work Began: 09/01/2002
Project Goals:
Wireless sensing capability is particularly useful for biohazardous environmental monitoring. In areas where concern for human exposure is a priority, the added flexibility a remote sensing scheme would provide dramatically increases the usefulness of present discharge-based sensors [1-3], in particular the microGeiger. Geiger counters are the detectors of choice when it comes to on-site survellience of radioactive material. The goal of this project is to develop a new wireless sensing scheme for discharge-based sensors such as micromachined Geiger counters.
Title:  Synthesis of Gold-Thiolate Nanoclusters for a Micro GC
Graduate Students: Michael P. Rowe (CHEM)	Faculty Advisor: Edward T Zellers (EHS) Work Began: 05/15/2002
Project Goals:
This project provides the thiolate-monolayer-protected gold nanoparticles (MPNs) that serve as the chemically sensitive interface layers of the WIMS µGC chemiresistor (CR) array detector. Novel materials and associated synthetic strategies are being developed. In addition to producing functionalized-thiolate MPNs for a "universal" vapor sensor array, composites that couple MPNs with organometallic compounds are being explored to enhance µGC performance in specific applications.
Title:  Ferroelectric Film-Based High-Efficiency Microvalves and Microsensors
Graduate Students: Raghav Vanga (PHYS-MTU)	Faculty Advisor: Miguel Levy (PHYS-MTU) Work Began: 01/01/2003
Project Goals:
The devices we propose to implement are low-power-consumption microvalves and microsensors based on single-crystal relaxor ferroelectrics. Our aim is to utilize the large electromechanical coupling efficiency and high sensitivity of lead zinc niobate (PZN-PT) and lead-magnesium niobate (PMN-PT) film piezos to develop valve actuation, pumping drives at low-voltages (below 10V) and low-power consumption, and biosensors.
Title:  Sub-One-Degree Per Hour High Performance Gyroscope
Graduate Students: Jae Yoong Cho (EECS) Funding Source: DARPA Post Doc: Sang Woo Lee (EECS), Junseok Chae (EECS)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 01/01/2005
Project Goals:
Micro-gyroscopes are used in the variety of fields including military, automotive, guidance, and consumer products. Micromachined gyroscopes have been developed for some of these applications. By taking advantage of small size, high precision, highly reliable, and low cost MEMS technology, the performance of micro-gyroscopes has steadily improved over the past two decades. Currently there are a number of “near inertial grade” micro-gyroscopes with resolution from one to tens of degrees/hr [1-3]. However, it is still necessary to develop a micro-gyroscope with resolution below 1 degree/hr for “inertial grade” sensing. This project aims to develop a micro-gyroscope which is capable of meeting the target resolution and bias stability of sub-one-degree/hr. The micro-gyroscope will be integrated in a high level vacuum package with superior temperature and shock immunity which is being developed under a DARPA project.
Title:  Portable Mesoscale System for Analysis of Complex Vapor Mixtures
Graduate Students: Qiongyan (Judy) Zhong (EHS), William H. Steinecker (CHEM), Chunguang Jin (EHS) Funding Source: NIOSH-CDCP	Faculty Advisor: Edward T Zellers (EHS) Work Began: 10/01/1998
Project Goals:
This project concerns the development of a portable gas chromatograph (GC) with several novel components and features and its application to several environmental monitoring problems. With this instrument, mixtures of volatile organic compounds (VOCs) are sampled, chromatographically separated at high speed, and then identified and quantified. Three different applications are explored: indoor air quality (IAQ) monitoring, determination of vapor phase environmental tobacco smoke (ETS) markers, and analyzing “signature” VOCs emitted by U. S. paper currency.
Title:  Micro Diffusional Vapor Sampler for a microGC
Graduate Students: Kate S. Hunt (CHEM), Jin Zheng (ECE-MTU), Yuxing Tang (ECE-MSU) Funding Source: NIOSH Other Investigators: Paul L. Bergstrom (ECE-MTU), Dean M. Aslam (ECE-MSU)	Faculty Advisor: Edward T Zellers (EHS) Work Began: 06/01/2005
Project Goals:
This project concerns the development of a passive microfabricated diffusional vapor sampler (µDVS) with integral thermal desorption heater, occupying a volume of ~0.15 cm3. Advantage is taken of the micron-scale dimensions of the device components to achieve high (pumpless) effective sampling rates, high preconcentration factors, and power-efficient desorption of ambient volatile organic vapors (VOCs). The goals of this project are to design, fabricate, and evaluate the performance of a prototype micro-diffusional vapor sampler (µDVS), assess performance relative to theoretical models of diffusional transport and adsorbent capacity for vapors commonly found as contaminants in indoor working environments, and interface the sampler with an array of microsensors to determine the feasibility of incorporating the µDVS into a microanalytical system for near-real-time vapor determinations.
Title:  High-Speed Chemical Sensing Using Microdischarges
Graduate Students: Bhaskar Mitra (EECS) Funding Source: NSF, USGS, Sea Grant	Faculty Advisor: Yogesh B Gianchandani (EECS) Work Began: 01/01/2003
Project Goals:
This project explores the use of spectral emission of microdischarges for chemical analysis. Spectroscopic methods of chemical detection offer high specificity, excellent sensitivity, and fast response time. On chip microdischarges offer an efficient way to distinguish chemical composition and concentration by spectral emission detection. This provides a versatile class of sensors for a wide variety of applications. In the present work, we have used these for detecting metal impurities in water, organic vapors in air, and biomolecules by direct and indirect fluorescence.
Title:  Optimized Processing Architecture for Multiple Acoustic Stream Analysis
Graduate Students: Fatima Otori (EECS-TU)	Faculty Advisor: Dale Joachim (EECS-TU) Work Began: 01/15/2004
Project Goals:
This project explores processing architectures applicable to small-scale, low-power multiple acoustic stream analysis sensors. The processing architecture must support all necessary data analysis, local management, and communication tasks in such sensors as small-scale, low-power acoustic direction finding. Power efficiency is attained by maximizing local processing (calibration, recognition, line-of-bearing estimation, and self-localization), thereby reducing sensor communication.
Title:  Modeling and Fabrication of a Six-Channel Cubic Silicon Microphone Array for Acoustic Direction-Finding
Graduate Students: D'Mark Hunter (EECS-TU) Other Investigators: Kensall D. Wise (EECS)	Faculty Advisor: Dale Joachim (EECS-TU) Work Began: 03/15/2004
Project Goals:
This project explores the design and fabrication of a six-microphone cubic array acoustic direction-finding sensor (Figure 1a). The outcomes of a related project, “Efficient Acoustic Direction-Finding Algorithms for Low Power Sensors” provide the required performance specifications. The project goals include modeling, optimization, and fabrication of the six-channel microphone cubic array to meet specified sensitivity and dynamic range.
Title:  An Electrochemical Interface for Integrated Biosensors
Graduate Students: Yue Huang (ECE-MSU) Funding Source: Michigan Economic Development Corp.	Faculty Advisor: Andrew J Mason (ECE-MSU) Work Began: 01/05/2005
Project Goals:
This project addresses critical technical challenges in interfacing bioelectronic sensors to integrated circuitry necessary to construct a lab-on-chip system. The integrated biosensors must provide continuous, accurate, and stable measurements of specific biochemical concentrations with output signals that can be addressed, amplified, and calibrated on chip and readily interfaced to a computer. This project seeks to develop and characterize an array of fully addressable, temperature controlled electrodes integrated via post-fabrication processing on a chip containing CMOS electrochemical readout circuitry.
Title:  Applications and Instrumentation for Comprehensive Two-Dimensional Gas Chromatography
Graduate Students: Cory S. Fix (CHEM) Funding Source: Jet Propulsion Laboratory	Faculty Advisor: Richard D Sacks (CHEM) Work Began: 07/01/2004
Project Goals:
The goals of this project are to investigate the preconcentration and 2-dimensional gas-chromatographic (GCxGC) modulation capabilities of polymer-coated microfabricated channels and to build a meso-scale instrument for rapid, high-modulation-frequency (~10 Hz) GCxGC analysis of organic vapor mixtures.
Title:  Ultra-Fast Vapor Determinations Using Micro-GC with Flame Photometric Detection
Funding Source: Honeywell	Faculty Advisor: Richard D Sacks (CHEM) Work Began: 01/07/2005
Project Goals:
This project focuses on the development of a sensitive, selective, and ultra-fast detector based on flame photometry (FP) technology.
Title:  Integrated Particle Counting and Potentiometric Sensor Array for Water Quality Analysis
Graduate Students: K. Jeff Campbell (ECE-UT) Funding Source: NSF Grant	Faculty Advisor: Richard B Brown (ECE-UT) Work Began: 09/19/2005
Project Goals:
This project will implement an all-electronic potentiometric and particle sensor array. A manufacturing process which facilitates mass-fabrication of nanopore sensors atop CMOS circuitry will be developed. Integrated electronics will greatly reduce the number of external connections between sensor and instrument, reducing noise and improving power budget. The micro-structure is also expected to be robust and offer improved reliability over existing sensors. Finally, the performance of completed sensors will be characterized and the behavior of an array of sensors will be optimized.
Title:  Growth of Conformal CNT Adsorbent Layers for a Micro GC and Sensors
	Work Began: 01/01/2006
Project Goals:
This project seeks to develop a technology for conformal deposition of high-density carbon nanotubes (CNTs) as adsorbent materials in the (thermally desorbed) vapor micropreconcentrator/ focuser (¦ÌPCF) module of the WIMS micro gas chromatograph (¦ÌGC). The work investigates the effect of synthetic conditions on CNTs adsorption and desorption properties and optimizing their performance.
Title:  A MEMS Gas Chromatograph
Graduate Students: Kate S. Hunt (CHEM), Shaelah M. Reidy (CHEM), Gordon R. Lambertus (CHEM), William H. Steinecker (CHEM) Other Investigators: Robert J. Gordenker (EECS)	Faculty Advisor: Edward T Zellers (EHS) Work Began: 09/01/2005
Project Goals:
This project concerns the assembly and optimization of a high-performance micro gas chromatograph (µGC) capable of capturing, preconcentrating, separating, and detecting the components of complex environmental vapor mixtures. An on-board microcontroller will be used for sequencing instrument functions, acquiring and buffering sensor data for upload to a host controller using a ZIGBEE standard wireless link.
Biomedical Sensors & Subsystems
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Title:  Diffusion Based Microgradient Array
Funding Source: WIMS ERC	Work Began: 09/01/2004
Title:  A Micromechanical Cochlear Processor
Graduate Students: Wen-Lung Huang (EECS)	Faculty Advisor: Clark T.-C. Nguyen (EECS) Work Began: 09/01/2000
Project Goals:
This project entails the design and demonstration of a micromechanical frequency selector for cochlear signal processing. Such a micromechanical frequency selector has advantages of better selectivity than electronic versions and zero dc power consumption. The long-term vision here is a signal processing device capable of attaining the speed and dynamic range similar to that of the biological cochlea.
Title:  An Articulated Package for Cochlear Prosthesis
Graduate Students: Benjamin Y. Arcand (ME-MTU)	Faculty Advisor: Craig R Friedrich (ME-MTU) Work Began: 01/15/2001
Project Goals:
Cochlear implants have become an accepted and successful treatment for profound, bilateral, sensorineural deafness in both children and adults. The tonotopic organization within the cochlea allows electrodes in multi-channel devices to stimulate localized sub populations of auditory nerves responsible for perception of various frequencies. The desired effect is to selectively stimulate the auditory neurons in a way that mimics the ear’s healthy functionality. Essential to effective and efficient localized stimulation of the auditory nerves is the position of the stimulating electrodes within the cochlea. However, the small size, delicate internal structures and helical shape of the cochlear chambers complicates the matter of precise positioning of the implant. The project goal is to provide deep and controlled insertion by means of a fully implanted micro-scale device.
Title:  Developing Methods for Optimal Implantation of Deep Brain Stimulus Electrodes Using Independent Component Analysis
Graduate Students: Andre E. Snellings (BME) Other Investigators: Wayne J. Aldridge (NEURO), Daryl R. Kipke (BME), Kensall D. Wise (EECS)	Faculty Advisor: David J Anderson (EECS) Work Began: 09/01/2001
Project Goals:
Deep brain stimulation (DBS) is a neurosurgical technique that has been applied for the treatment of tremor or motor symptoms associated with advanced Parkinson’s disease, and in the near future could be applied to treat other ailments such as epilepsy or chronic pain. This project addresses neurological guidance issues encountered in the search phase of DBS electrode implantation to small, very specific targets in the deep brain. The current state-of-the-art for target localization relies on electrophysiological recordings made during the procedure, immediately prior to implant. This project explores the benefits of using a multiple site close-spaced recording electrode array and signal processing techniques to provide a more accurate representation of the neural environment, and thus improve the efficiency of the implantation.
Title:  Cortical Mapping
Graduate Students: Gregory J. Gage (BME), Nicholas B. Langhals (BME), Kip A. Ludwig (BME), Timothy Marzullo (BME), Hirak Parikh (BME), Shani E. Ross (BME) Undergraduate Students: Johann Dudley (BME), Bahareh Aslani (BME), Mark Hanus (BME), Chie Kawahara (BME), Elizabeth Kim (BME), Joshua Kinnison (BME), Charles Miller (Psychology), Shruti Sheorrey (EECS), Joseph Tchorzynski (BME)	Faculty Advisor: Daryl R Kipke (BME) Work Began: 03/01/2005
Project Goals:
Goals of this project are to characterize the laminar structure of cortical columns during motor learning and to investigate the use of local field potentials at specific layers of the cortex for use in brain machine interface tasks. This research thrust also investigates non-invasive electrocortiogram (ECoG) recordings and their relationship with the cortical recordings.
Title:  Hybrid Neural Implant Systems
Graduate Students: David S. Pellinen (BME) Funding Source: NIH/NINDS	Faculty Advisor: Daryl R Kipke (BME) Work Began: 09/01/2001
Project Goals:
The main project goal is to develop and validate polymer-based intracortical recording/drug delivery electrodes. Another project goal is to aid in developing hybrid neural implant systems for neurosurgical applications including chronic micro-drug delivery. The hybrid neural implant systems consist of silicon or polymer substrate intracortical microelectrode arrays that are integrated with polymer interconnects for trans-dural communication. The system mounts on a permanently implanted base platform with percutaneous connectors and/or active circuits including telemetry.
Title:  An Ultraminiature Microsystem for Untethered Data Gathering
Graduate Students: David F. Lemmerhirt (EECS) Undergraduate Students: David A. Fick (EECS) Funding Source: Polly Anderson Gift Fund Other Investigators: Joseph M. Giachino (EECS)	Faculty Advisor: Kensall David Wise (EECS) Work Began: 09/01/1998
Project Goals:
The past decade has seen the emergence of a variety of microsystems, ranging from very small systems with single-domain sensing and wireless communication to larger, reconfigurable systems with bus-interfaces and multi-domain sensing/actuation. This project addressed the need for versatile microsystems that are capable of multi-sensor data acquisition and storage/transmission, and yet are extremely compact. The goal of the project was to develop technology for microsystem miniaturization, and to demonstrate an autonomous microsystem smaller than 0.5cc that acquires and stores data from multiple environmental and biological sensors.
Title:  A Position Sensing and Control System for a Cochlear Prosthesis
Graduate Students: Jianbai (Jenn) Wang (EECS) Other Investigators: Bryan E. Pfingst (OTO), David J. Anderson (EECS), Jamille F. Hetke (EECS), Teresa A. Zwolan (OTO), Dean M. Aslam (ECE-MSU), Craig R. Friedrich (ME-MTU)	Faculty Advisor: Kensall David Wise (EECS) Work Began: 05/01/2000
Project Goals:
In cochlear prostheses, the distance between the electrode array and the neural receptors along the scala tympani is critical in determining optimal stimulus levels and frequency resolution. In completely implantable systems, where power must be minimized, it is especially important that stimulus levels be optimized. This project will develop position-sensing devices capable of measuring array-wall distance to a resolution of 40μm or better. Insertion devices capable of placing such arrays deep within the cochlea for maximum frequency range capability will also be developed, and automatic closed-loop positioning systems for use during insertion and, perhaps, during use will be considered. The goal is to combine position sensors based on either polysilicon/diamond strain gauges or ultrasonic devices with pneumatic positioning actuators using micromilled backing tubes to create closed-loop position control, allowing the adaptive setting of stimulus levels and profiles.
Title:  Characterizing the Effects of Electrical Stimulation of the Inferior Colliculus on Cortical Activity: Implications for a Midbrain Auditory Prosthesis
Graduate Students: Hubert H. Lim (BME) Funding Source: NIH/NIDCD, NIH/NIBIB	Faculty Advisor: David J Anderson (EECS) Work Began: 06/01/2001
Project Goals:
This research is focused on characterizing the inferior colliculus central nucleus (ICC) to the primary auditory cortex (A1) neural projection using electrical stimulation of the ICC. By better understanding the effects of varying stimuli on different subpopulations of ICC neurons and their projections to A1, it will become clearer as to how the central auditory system codes and transmits neural information to the cortex and eventually elicits an auditory percept. In a practical sense, such information can be utilized to determine the feasibility and some parameters for developing and implementing a midbrain auditory prosthesis (MAP) that may outperform current auditory implants.
Title:  A Micromachined Sieve Electrode for Chronic Recording from Multiple, Isolated Gustatory Nerve Fibers in the Rat Peripheral Nervous System
Graduate Students: Stefan A. Nikles (BME) Funding Source: NIH/NINDS Other Investigators: Robert M. Bradley (DENT)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 09/01/1998
Project Goals:
This project seeks to develop high-density micromachined electrodes for chronically recording neural signals from the peripheral nervous system (PNS) using the nerve regeneration principle. The electrode consists of an 8μm polyimide substrate that contains an array of several through-holes with diameters ranging from 2 to 100μm. Electroplated gold recording sites are located around the holes. When the electrode is placed in between the two ends of a nerve, the fibers regenerate through the holes and connect with their target sites. Neural signals passing through the fibers are detected by the recording sites located around the holes. Because of the fixed position of the recording site with respect to the nerve fiber, high-quality action potentials can be recorded over an extended period of time. The recorded signals are carried to the probe backend via an integrated ribbon cable. The backend is connected to a percutaneous connector, allowing access to all the channels on the probe. The goal of this project is to record from multiple, isolated fibers in the nervous system chronically. This will allow specific physiological questions to be answered regarding the long-term stability of the taste receptors in the tongue, as well as their synaptic connections to the nervous system. Future applications may provide interfaces between a prosthetic device and the nervous system.
Title:  A Chronic Drug-Delivery Probe with Integrated Microvalves and Closed-Loop Circuitry
Graduate Students: Kyusuk Baek (EECS) Funding Source: NIH/NCRR/NIBIB Other Investigators: David J. Anderson (EECS), Daryl R. Kipke (BME), Sanford Bledsoe (OTO)	Faculty Advisor: Kensall David Wise (EECS) Work Began: 05/01/2001
Project Goals:
The goal of this research is to incorporate an integrated drug delivery system, including microchannels, flowmeters, microvalves and micropumps, into an active chronic probe. The 3-D recording sites of the probe will make it possible to acquire 3-D images of electrical activity in the brain. The drug delivery system will manipulate these images by delivering pharmaceuticals to the target volume of tissue. The desired chemicals will be directed to the proper sites under the control of microvalves to allow multi-site, multi-chemical injection while minimizing the fluidic lead count. Finally, on-chip circuitry will be used to actuate the valves, control the drug delivery, and provide feedback to the system on the basis of the recorded action potentials.
Title:  An Integrated Chemical Delivery Probe with In-Line Flow Measurement
Graduate Students: Yang Li (EECS) Funding Source: NIH/NCRR Other Investigators: David J. Anderson (EECS), Sanford Bledsoe (OTO)	Faculty Advisor: Kensall David Wise (EECS) Work Began: 05/01/2000
Project Goals:
This project seeks to develop in-line flowmeters for use on neural probes that are capable of selective chemical delivery as well as electrical recording and stimulation at the cellular level. Today, drug injection is open-loop such that flow is assumed to result from the application of drive pressure, ignoring possible channel blockage. Flowmeters capable of sensing velocities of 1-10cm/sec and corresponding flows as low as 100pL/sec are being developed based on pulsed heaters supported on dielectric membranes over the flow channel. The fast thermal time constants and pulsed operation of these structures help limit any tissue heating to less than 2°C. In designing such delivery systems, device designs must be upward compatible with current probe fabrication technology and compatible with chronic use in vivo. High actuation voltages (>10V) are precluded in order to avoid excessive electrical stress across dielectrics and temperature rises in tissue must be no more than 2°C to avoid neural damage. Moreover, the entire delivery system must be very small to avoid excessive tissue displacement and disruption of the cellular system.
Title:  Chronically-Compatible Silicon Microprobes for Neuroscience and Neural Prostheses
Graduate Students: Gayatri E. Perlin (EECS) Funding Source: NIH/NINDS Other Investigators: Jamille F. Hetke (EECS), Daryl R. Kipke (BME)	Faculty Advisor: Kensall David Wise (EECS) Work Began: 01/01/2003
Project Goals:
Silicon micromachined electrode arrays are nearing the point where they are ready for use in prostheses aimed at a number of neurological disorders, including deafness, paralysis, blindness, epilepsy, and Parkinson’s disease. Silicon processing has become the enabling technology for high-density electrode arrays, and using silicon-based micromachining, various recording and stimulating probes have been created over the past three decades. Still, there is an increasing demand for arrays having dozens or hundreds of sites and interest in using multiple sites both to allow improved understanding of biological neural networks and for the implementation of neural prostheses. This project seeks to address various fundamental issues related to the long-term use of silicon microprobes for neuroscience and human prostheses. The main aspects of this project involve the development and validation of advanced chronically compatible configurations of silicon electrode structures, studies of material durability in vivo and circuit design and integration of a highly robust front-end circuit for a fully implantable system for neural prostheses. The recording probe shown in Figure 1 was developed to be minimally invasive in tissue. This structure should allow the tissue to re-grow around the probe after insertion and anchor it in place reducing irritation due to micro-motion. The biocompatibility studies of silicon and thin-film materials used on the probe structures is taking place in vivo, as well as through accelerated lifetime testing in saline. This project also contributes to the design and testing of the fully implantable neural recording array which includes integrated circuitry for site selection, signal amplification, signal processing and a bi-directional wireless interface between the body and the external environment. The first version of this system is shown in Figure 2. The contribution of this project to the implantable system includes probe and front-end circuit design. The front-end circuitry includes a multiplexer design allowing the possibility of electronically scanning a subset of a large number of recording sites, thus reducing the lead count of the system. It also includes low noise preamplifiers specifically designed to amplify neural signals in the range of a few hundred microvolts occurring in the bandwidth of a few hundred hertz to about 10KHz.
Title:  Ultra-Sensitive Poly-C Position Sensors for Cochlear Prosthesis
Graduate Students: Yuxing Tang (ECE-MSU), Zhenwen(Louise) Peng (ECE-MSU), Jianbai (Jenn) Wang (EECS) Other Investigators: Kensall D. Wise (EECS)	Faculty Advisor: Dean M Aslam (ECE-MSU) Work Began: 09/01/2000
Project Goals:
This project focuses on designing, fabricating, and testing of the cochlear probe with integrated poly-crystalline diamond (poly-C) strain gauge. It also focuses on developing poly-C techonology for other sensor application such as in harsh environment and at high temperature.
Title:  Microscale Convective Flows Driven by Non-contact Micromachined Thermal Probes
Funding Source: Whitaker Foundation, University of Michigan	Work Began: 08/01/2004
Title:  Electrokinetic Pumps for Dynamic Actuation of Cochlear Implants During Surgical Insertion
Graduate Students: Meng-Ping Chang (ME) Other Investigators: Kensall D. Wise (EECS)	Faculty Advisors: Work Began: 09/01/2003
Project Goals:
A key difficulty in using cochlear implants is that typical implants can only be inserted a limited distance into the cochlea, due to the imperfect match of the helical electrode array to the shape of the cochlea, the limited compliance of the array, and, in some cases, to the ossification of the insertion path itself. This suggests the need for a dynamically controlled “backing device" to allow control over the local shape of the implant using on-board sensors and actuators. Such a device should allow deeper insertion and, by detecting contact with the scala tympani wall, should minimize insertion trauma. Significant progress has been made in the fabrication of the backing device. The candidate device is pneumatically controlled and consists of a number of molded inflatable chambers, akin to the way a Bourdon tube unrolls when pressurized. However, relatively high pressures (~60+psi) are needed in the present version of this device, which presents two problems: (1) High pressure implies the possibility of harming the patient in case of device failure. (2) It is desirable to independently inflate several segments of the backing device to various pressures in order to control the local radius of curvature, which leads to the need for either several independent external pressure regulators or a small array of micropumps. This project is exploring a relatively new pumping technology, the electrokinetic pump, which solves all of these problems and should make it possible to form literally hundreds of pumps onto a single wafer.
Title:  A 1024-Site Neural Stimulating Array with On-Chip Current Generation
Graduate Students: Ying Yao (EECS) Funding Source: NIH/NINDS Other Investigators: David J. Anderson (EECS)	Faculty Advisor: Kensall David Wise (EECS) Work Began: 09/01/1999
Project Goals:
Several generations of active stimulating electrodes with CMOS circuitry have been developed for use in the central nervous system [1]. Next-generation neural prostheses will require thousands of stimulating sites in densely packed 3D electrode arrays. This project developed such arrays (STIM-3) using a 64-site probe as a test vehicle. Low-profile structures (to allow the probe circuitry to be folded flat over the cortex) were explored along with extensive self-test strategies to allow testing at both wafer-level and pre-assembly level.
Title:  A 128-Site 16-Channel Electrode Array for a Cochlear Prosthesis
Graduate Students: Pamela T. Bhatti (EECS) Funding Source: J. Reid and Polly Anderson Gift Fund Other Investigators: Jamille F. Hetke (EECS), Teresa A. Zwolan (OTO), Craig R. Friedrich (ME-MTU)	Faculty Advisor: Kensall David Wise (EECS) Work Began: 01/01/2000
Project Goals:
This project is developing a 128-site 16-channel electrode array as a cochlear prosthesis for the profoundly deaf. By placing the electrical stimulation sites in a high-density configuration (250μm pitch), this device offers the potential for greater frequency resolution, leading to enhanced speech recognition. The application requires multi-level metal interconnect with high-quality interlevel dielectrics. Conformally deposited parylene encapsulation and wafer-level site parylene removal will also be explored. System-level issues including biphasic stimulus current generation, built-in self-test, and adaptive stimulus amplitude control based on neural response recordings and array position information will be addressed.
Title:  Neurochemical Sensing With MEMS-Based Microelectrode Arrays
Graduate Students: Matthew D. Johnson (BME), Robert K. Franklin (EECS), Matthew D. Gibson (BME) Undergraduate Students: Olivia Kao (BME), Katherine Scott (BME) Funding Source: NIH Other Investigators: Richard B. Brown (ECE-UT)	Faculty Advisor: Daryl R Kipke (BME) Work Began: 09/01/2003
Project Goals:
Many disabling brain disorders manifest themselves in abnormal fluctuations of neurotransmitters that is, the chemicals involved in transmitting signals among neurons. The major outcome of this project is the development and application of MEMS-based neural probe systems for multi-channel neurochemical sensing in-vivo. This project seeks to: 1) design electrode site configurations to maximize sensitivity while minimizing electrode area for high spatial resolution; 2) develop site-specific coating techniques to improve analyte sensitivity and selectivity; 3) develop hardware for simultaneous multi-channel neurochemical recordings; 4) develop models for biofouling of implanted neurochemical probes; and 5) investigate intervention strategies to prolong implanted neurochemical probe lifetimes. Together, this probe technology may provide scientists and clinicians with a more robust picture of the neural interface and enable them to provide more precise dosage and timely delivery of therapeutic strategies.
Title:  Advanced Neural Interfaces
Graduate Students: Taegyun Moon (BME), John P. Seymour (BME), Erin K. Purcell (BME), Jeyakumar Subbaroyan (BME) Undergraduate Students: Risheng Xu (Biology), Samana Ghirmire (BME), Joseph Maliakkal (Biochemical), Jacqueline Gauthier (Biology), Marc Kaplan (BME), Michael Charters (BME), Greg Chen (EECS), Iqbaljit Kahlon (BME)	Faculty Advisor: Daryl R Kipke (BME) Work Began: 09/01/2003
Project Goals:
The longevity of neural prosthetics may be greatly improved by optimizing the tissue electrode interface. Studies have shown that microglia, astrocytes, and extracellular matrices can form encapsulation layers and in some cases electrically shield a neural probe's electrode sites from healthy neural tissue [1, 2]. The reactive tissue response at the neural interface includes both an early anti-inflammatory response due to insertion trauma and a sustained response induced in part by the interplay among micromotion [3], tethering, and device biocompatibility [4, 5]. The longevity of the neural electrode implant has been limited by this reactive tissue encapsulation of the implant [5-7]. The goal of this project is to minimize the reactive tissue response and its effects on the recording capabilities.
Title:  Development of an Oxygen Microgradient Chip
Graduate Students: Jaehyun Park (EECS), Tushar Bansal (EECS) Funding Source: Start-up Funds	Faculty Advisor: Michel Martin Maharbiz (EECS) Work Began: 09/01/2003
Project Goals:
The oxygen microenvironment within tissue plays a crucial role in many biological processes and the treatment of many diseases. No technology currently exists that allows the researcher to control localized oxygen doses and impose arbitrary oxygen gradients within tissue with microscale resolution. Our primary goal is to develop an oxygen microgradient chip that allows control of the oxygen environment in a tissue sample or microbial culture with microscale spatio-temporal resolution. Our fabricated device generates 1-D and 2-D dissolved oxygen gradients across several millimeters with microscale precision and has the potential to test the effect of localized oxygen delivery on a wide range of tiny animals, tissues, and cell samples. Importantly, user-defined microgradient profile is generated at the time of the experiment, adjustable during the course of an experiment, and actively responsive to transient experimental conditions.
Title:  Optimization of the Chronic Microelectronic -Tissue Interface
Graduate Students: Tushar Bansal (EECS) Other Investigators: Kensall D. Wise (EECS), Daryl R. Kipke (BME)	Faculty Advisor: Michel Martin Maharbiz (EECS) Work Began: 01/01/2004
Project Goals:
Past neural probe development has been based on silicon technology and has produced a wide variety of devices capable of interfacing with the nervous system at the cellular level; however, in chronic single-unit recording situations, the formation of a thin (3-5µm) sheath of protein and glia over the probe surface can lead to a loss of signal amplitude. This project seeks to explore alternatives to the current probe structure that can actively dose compounds into the neural tissue. We seek specifically to explore the use of doped polymers under the sites that can be activated electronically to release neurologically active compounds or chemicals capable of removing protein on the sites, incorporate cells under the sites to produce a chronic interface to the surrounding tissue via its processes, and explore the use of polymers on the probe shanks to improve their compliance while maintaining enough stiffness to permit insertion. Coatings capable of stiffening the probes as inserted, but then dissolving over time to produce a flexible implant may also be explored.
Title:  A Multi-Chambered Monolithic Actuated Cochlear Prosthesis Insertion Tool
Graduate Students: Abhay M. Kulkarni (ME-MTU)	Faculty Advisor: Craig R Friedrich (ME-MTU) Work Began: 09/01/2005
Project Goals:
Cochlear implants have become an accepted and successful treatment for profound, bilateral, sensorineural deafness in both children and adults. Cochlear implants are greatly benefiting the profoundly deaf by restoring partial auditory function. The performance of such an implant is dependent in large part on its deep and controlled insertion in the scala tympani chamber of the spiral-shaped cochlea. Thus there is a need of an actuated insertion tool for deeper insertion and controlled positioning of the implant’s array of electrodes. As a solution a monolithic single chambered insertion tool was developed by the photolithography process[1]. The goal of this project is to develop a multi-chambered monolithic actuated insertion tool, and to integrate the actuating method with this tool.
Title:  Transpiration Actuation
Graduate Students: Ruba T. Borno (EECS) Funding Source: EECS Department	Faculty Advisor: Michel Martin Maharbiz (EECS) Work Began: 06/01/2004
Project Goals:
We have developed a class of microactuators powered by surface tension and evaporation. The devices presented here are inspired by a fern spore-release structure that generate forces due to the same Laplace-Young pressure mechanism that leads to conventional MEMS wet-release stiction. These actuators are ideal for applications where power or energy scavenging from the environment is desirable. We envision deployed microsystems capable of actuating and self-assembling in the field with little or no need for electricity.
Title:  Feedback Control of a Pressure Regulating System for the Dynamic Actuation of a Cochlear Prosthesis Insertion Tool
Graduate Students: Nishit Nagar (ME-MTU)	Faculty Advisor: Craig R Friedrich (ME-MTU) Work Began: 09/15/2004
Project Goals:
Cochlear implants are used to restore partial auditory function to the profoundly deaf. The performance of such an implant is dependent in large part on its deep and controlled positioning in the spiral-shaped cochlea of the ear. The project's goal is to develop a system that ensures controlled insertion using feedback from strain gauges mounted on the implant.
Title:  A Neural Stem Cell-Seeded Hydrogel Coating for Chronic Neural Probes
Funding Source: MEDC and NSC	Work Began: 06/01/2004
Project Goals:
1. Successfully seed and maintain viable, undifferentiated neural stem cells in an alginate hydrogel scaffold. 2. Determine the optimal scaffold composition for the cells based on the best combination of viability, growth factor release, and mechanical stability. 3. Using the chosen scaffold composition, demonstrate a reduced glial response in seeded, coated probes versus hydrogel-alone coated probes, cells alone with probe, and probe alone controls. 4. Demonstrate improved long-term recordings with seeded, coated probes versus controls.
Title:  Frequency Modulation of Local Field Potentials in Rat Cortex
	Work Began: 07/01/2005
Title:  A Neural Probe With Integrated Electrowetting-Based Microfluidics for Chronic Drug Dosing
Graduate Students: Meng-Ping Chang (ME) Other Investigators: Daryl R. Kipke (BME)	Faculty Advisor: Michel Martin Maharbiz (EECS) Work Began: 01/01/2006
Project Goals:
Precise manipulation of liquid transport in the range of sub micro-liter is always a challenge for drug delivery applications. The conventional way for transporting liquid in a microsystem is to use an electromechanical or electrochemical micropump to move a continuous liquid column. The pump-and-flow approach is straightforward and efficient but lacks precise volume control of liquid movement if there exists no extra active valving systems for stopping the flow. The pressure generated by the micropump may cause damage to the patient during drug injection as well. These problems can be solved by moving a discrete liquid droplet instead of a bulk liquid flow. The goal of this project is to investigate drug droplet transport assisted by electrowetting-based microfluidic devices in a chronic neural probe. This device includes a droplet dispenser that generates discrete droplet from liquid in a built-in reservoir, an actuator for droplet transport in the micro channel, and a microvalve to switch the drug-dosing pore; all of which are assisted by the electrowetting actuator.
Title:  Wireless Micropower Intraocular Pressure Sensor
Graduate Students: Razi-ul M. Haque (EECS), Beth Isaksen (EECS) Other Investigators: Dennis M. Sylvester (EECS)	Faculty Advisor: Kensall David Wise (EECS) Work Began: 01/03/2006
Project Goals:
This project intends to further develop previous work in the field of implantable pressure sensors by addressing wireless communication techniques, ultra-low power microcontrollers, and the incorporation of a specially-designed power source. By targeting a specific application, we hope to reduce the limitations of glaucoma treatment while simultaneously presenting a platform that may also have the ability to sense other parameters of interest from within the body. The possibility of generating a modular solution with long-term recording, simple wireless interrogation, and programmability increases the potential applications for such a device.
Wireless Interfaces
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Title:  Low-Power UHF Micromechanical Voltage-Controlled Oscillator (VCO)
Graduate Students: Jing Wang (EECS)	Faculty Advisor: Clark T.-C. Nguyen (EECS) Work Began: 09/01/2000
Project Goals:
This project aims to demonstrate a voltage-controlled oscillator utilizing a tunable, UHF, micromechanical resonator as its high-Q frequency-setting element that is capable of achieving low phase noise while consuming very little power compared with present-day synthesizers.
Title:  UHF Micromechanical Transmit Filters
Graduate Students: Sheng-Shian Li (EECS)	Faculty Advisor: Clark T.-C. Nguyen (EECS) Work Began: 09/01/2001
Project Goals:
Although capable of record-breaking on-chip frequency shaping, the micromechanical filters demonstrated to date have trouble processing high-power signals, such as commonly seen in the transmit path of wireless communication devices. This project aims to realize micromechanical filters at GHz frequencies capable of handling power levels typically seen in the transmit path of wireless communication devices. The goals of this project are not necessarily bound by the requirements of the ERC; they in fact intend to raise the power handling threshold of micromechanical filters beyond the requirements of the ERC.
Title:  Quadrature Mixer-Filter
Graduate Students: Mustafa U. Demirci (EECS) Funding Source: DARPA	Faculty Advisor: Clark T.-C. Nguyen (EECS) Work Began: 05/01/2001
Project Goals:
This project entails the design and demonstration of a micromechanical mixer-filter with a quadrature-cancelling mechanism that removes the RF image before processing a signal. This filter will operate at IF (e.g., 100-200MHz) and is the key component in the ERC transceiver architecture that allows removing the low-noise amplifier (hence, offering enormous power savings). A major objective in this project is demonstrating noise figures less than 3dB, which then allows elimination of the LNA. In addition to implementing the mechanical circuit needed for mixer-filtering, the low-power, low-noise IF amplifier to follow this device will also be realized and integrated together with it on a single chip.
Title:  Micromechanical Resonator Reference Oscillator
Graduate Students: Seungbae Lee (EECS), Yu-Wei Lin (EECS) Funding Source: DARPA/MTO	Faculty Advisor: Clark T.-C. Nguyen (EECS) Work Began: 01/01/1999
Project Goals:
This project intends to demonstrate a high-Q, low phase noise, 10MHz micromechanical resonator oscillator for use as an on-chip reference oscillator in wireless transceivers that satisfies the strict GSM phase noise specifications of less than -130dBc/Hz at 1kHz offset frequency from a 13MHz carrier, and below -150dBc/Hz at far-from-carrier frequencies. Variations of the oscillator will utilize free-free beam or wine-glass disk micromechanical resonators specifically designed to handle sufficient power levels so as to allow them to achieve adequate far-from-carrier phase noise in an oscillator circuit. In addition to implementing this oscillator, this project intends to study stability-limiting phenomena unique to micro-scale resonator oscillators, such as mass loading noise, power handling limitations, nonlinearity, and aging.
Title:  A Miniature High-Impedance Antenna
Graduate Students: Nader Behdad (EECS)	Faculty Advisor: Kamal Sarabandi (EECS) Work Began: 01/09/2001
Project Goals:
This project entails the design and demonstration of miniaturized antennas with the possibility of providing high-impedance match to a bank of MEMS filters planned for the front end of the wireless interface. The antennas need to be placed above ground plane which limits their radiation efficiency and reduces the bandwidths. Reducing the size, increasing the bandwidth, and improving the efficiency of the antenna in the presence of the ground plane are problems that will be addressed.
Title:  A Transponder Design for Low-Power Wireless Applications
Graduate Students: Fatih Kocer (EECS)	Faculty Advisor: Michael P Flynn (EECS) Work Began: 01/01/2002
Project Goals:
The goals of this project are power efficient transmission of data from a sensor and the efficient transfer of power by RF means to a sensor. We propose low-voltage power telemetry and power efficient methods for clock extraction and transmission of data in the radio frequency (RF) range for long range telemetry applications.
Title:  Low-Power Transmitter for IEEE 802.15.4 Wireless Sensor Networks
Graduate Students: Mark A. Ferriss (EECS) Funding Source: Intel	Faculty Advisor: Michael P Flynn (EECS) Work Began: 09/01/2003
Project Goals:
Until recently, the main focus of the wireless industry was on communication with high data throughput. This neglected a variety of applications that require simple, low-power wireless connectivity with relaxed throughput and latency. The aim of this research is to develop a wireless transmitter for a low-power sensor node compliant with the IEEE 802.15.4 [1] wireless standard. Existing transmitters using proprietary wireless technologies (e.g., Bluetooth) consume too much power for these applications. Consequently, this work will also focus on minimizing cost, size, complexity, and power.
Title:  Deep Submicron CMOS Flash Analog-to-Digital Converters
Graduate Students: Sunghyun Park (EECS) Funding Source: Intel Fellowship, Intel Research Grant	Faculty Advisor: Michael P Flynn (EECS) Work Began: 08/01/2002
Project Goals:
The ADC has become a bottleneck in the design of electronic systems that process both analog and digital signals. High-speed ADCs in CMOS are being investigated in this project. Clock speeds of up to 4GHz are being pursued. Very fast ADCs are required for both ultra wide-band radio and software radio.
Title:  Energy-Efficient Networking Mechanisms for Environmental Monitoring Wireless Sensor Networks
Graduate Students: Chih-fan Hsin (EECS)	Faculty Advisor: Mingyan Liu (EECS) Work Began: 01/01/2002
Project Goals:
We focus on a large class of wireless sensor networks that are designed and used for monitoring and surveillance. Under our scenario, sensors usually have very limited energy. Therefore, energy-efficient designs are very important to have a long-lasting network. We study how to save sensors’ energy consumptions by turning off redundant sensors. We also study general energy-efficient protocol designs, e.g., the routing protocols. Furthermore, one of the most important mechanisms underlying the systems of interest is the monitoring of the network itself; that is, the control center needs to constantly be aware of the existence/health of all the sensors in the network for security reasons. We present plausible alternative communication strategies that can achieve this goal, and then develop and study in more detail a distributed monitoring mechanism that aims at localized decision making and minimizing the propagation of false alarms.
Title:  Large-Scale Data-Gathering Wireless Sensor Networks: Organization, Capacity, and Energy Efficiency
Graduate Students: Enrique J. Duarte-Melo (EECS) Funding Source: NSF-ITR small	Faculty Advisor: Mingyan Liu (EECS) Work Began: 01/01/2001
Project Goals:
Many-to-one communications are system-level abstractions of the communications' nature in a wide range of sensor network applications. However, there is a lack of understanding as to the properties and implications of this type of communications. It is not known how the network organization affects energy consumption or capacity. Furthermore, it is not known how these properties scale with the size of the network. This project seeks to gain understanding on the properties of large scale wireless sensor networks by studying the many-to-one communications.
Title:  Wireless FM Microsystems-on-Chip for Multichannel Biological-Electronic Interfacing
Graduate Students: Pedram Mohseni (EECS) Funding Source: NIH Other Investigators: Robert M. Bradley (DENT)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 09/01/1999
Project Goals:
Wireless recording of neural activities from a biological host contributes to neurosciences such as neuroethology. For such an experiment, implantable microelectrodes are essential tools, as well as telemetry systems, due to their advantage of simultaneous recording of nerve signals. The majority of the current neural recording systems utilize external surface mount components in a board-level discrete design having prohibitively large size and power consumption that makes them impractical for general-purpose low-power applications. In this project, a low-power standalone wireless multichannel microsystem will be developed and fully characterized for a variety of biomedical recording applications. Specifically, these microtelemetric systems will be interfaced with micromachined polyimide neural recording sieve electrodes to monitor the taste function in unrestrained laboratory rats.
Title:  Wireless Monitoring of Sports Equipment Using MEMS Inertial Sensors
Graduate Students: Sang Won Yoon (EECS), Kevin W. King (ME) Funding Source: University of Michigan Other Investigators: Noel C. Perkins (ME)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 07/01/2002
Project Goals:
MEMS and WIMS are being increasingly used in a variety of applications, including some consumer products. MEMS inertial sensors have been particularly of interest and have been used in automotive systems, inertial navigation/guidance, and position sensing. One application of miniature inertial sensors is in sports and sports equipment where there is interest in monitoring the movements and inertial forces involved in their use. By measuring all acceleration and angular rotation components of an object, it is possible to extract out information about its usage. For example, information about a golf swing can be very useful to the user in correcting and improving the swing. To do this conveniently, a small wireless system that includes inertial sensors for measuring inertial data about all three axes is needed. This project seeks to develop such a wireless microsystem and demonstrate its use in a variety of sports equipment.
Title:  UHF Micromechanical Receive Filters
Graduate Students: Yuan Xie (EECS) Funding Source: DARPA/MTO	Faculty Advisor: Clark T.-C. Nguyen (EECS) Work Began: 12/01/2002
Project Goals:
This project investigates methods for achieving high-Q μmechanical resonators and filters that operate at UHF frequencies. Bandpass filters for band or channel selection in wireless transceivers are of particular interest, and these are achieved by interlinking mechanically vibrating components in networks that realize the desired bandpass transfer functions. With Q’s in the thousands or even tens of thousands, μmechanical resonators are very well-suited to this application and should be able to achieve insertion losses less than 1dB for very small percent bandwidth filters.
Title:  High Frequency Batteryless Transponder Nodes
Graduate Students: Dan Shi (EECS)	Faculty Advisor: Michael P Flynn (EECS) Work Began: 12/01/2004
Project Goals:
There is a requirement for long range wirelessly powered high-rate date devices, for applications such as RFID, and wirelessly powered sensors and sensor networks. This project investigates efficient transmission of wireless power to devices in the wireless sensor network, so that a completely wireless sensor network without batteries can be realized. Operating frequencies in excess of 5GHz are being investigated to lower the size of the antenna size. Miniature antennas and miniaturized on-chip antennas are also being studied.
Title:  Digitally Corrected Folding ADCs
Graduate Students: Ivan T. Bogue (EECS) Funding Source: EECS Fellowship, WIMS, Intel	Faculty Advisor: Michael P Flynn (EECS) Work Began: 09/01/2002
Project Goals:
This work involves developing digital calibration techniques for folding analog-to-digital converters. According to the 2001 International Technology Roadmap for Semiconductors, improved ADC technology is a key factor in developing present and future applications. The switched-capacitor (SC) pipeline technique is the most popular method of implementing moderate resolution ADCs. However, the advantages of CMOS, which originally made SC circuits feasible, are being eroded by process scaling. Good switches and opamps are becoming increasingly difficult to design. Traditional ADC schemes do not work well with supply voltages of 1.8V and below. Furthermore, the performance required by present and future wireless and IT applications will not be met by the present-day ADC circuits techniques. Traditional ADC schemes are highly dependent on analog circuit performance, in particular on device matching. Because of the high analog content of these designs, these circuits are very difficult to modify or port to other processes. Because digital circuits scale well, a digital offset technique was developed. This allows allows a relaxation of analog circuit matching requirements.
Title:  A Wireless Implantable Micro-System for Multi-Channel Neural Recording
Graduate Students: no graduate student Funding Source: NIH/NINDS Other Investigators: Kensall D. Wise (EECS), Daryl R. Kipke (BME)	Faculty Advisor: Khalil Najafi (EECS) Work Began: 10/01/2004
Project Goals:
Chronic recording of multichannel neural electrical activity by microprobes is desirable and extensively used for understanding the operation of the nervous system, and for implantable prostheses. This project deals with the design and implementation of an implantable microsystem for wireless recording of neural signals. The system is powered and controlled through a wireless inductive RF link, and transmits recorded neural signals to the outside world through a wireless link. Figure 1 illustrates the general architecture of the wireless implantable microsystem.
Title:  Low-Power MICS Transceiver
Graduate Students: James D. Griggs (ECE-NCAT), Zheng Wang (ECE-NCAT) Other Investigators: Michael P. Flynn (EECS)	Faculty Advisor: Numan S Dogan (ECE-NCAT) Work Began: 03/01/2004
Project Goals:
Low-power Medical Implant Communication System (MICS) transceiver is being developed for the cochlear testbed. Cochlear implants are now established as a new option for individuals with profound (sensorineural) hearing impairment. Stringent low-power requirements for implant electronics dictate power/performance optimization. 0.18 micron RF/Mixed-Signal CMOS process is used for the design and implementation of a single-chip MICS transceiver. Our current target power consumption is 2mW from a 1 Volt supply. Sleep mode will be employed to reduce power consumption during idle times. MICS occupies the frequency spectrum from 402MHz to 405MHz.
Title:  A Low-Power CMOS Super-Regenerative Receiver
Graduate Students: Jia-Yi Chen (EECS)	Faculty Advisor: Michael P Flynn (EECS) Work Began: 09/01/2004
Project Goals:
Wireless communication has experienced exponential growth due to the need for connectivity and data exchange. Most communication systems focus on quality of service factors such as high data rate and wide coverage area. However, applications such as implantable neuroprosthetic devices, wireless sensors, and home automation have completely different characteristics. These only need short communication range and low data rate, but power consumption must be very low to enable long lifetime. With these constraints, the design philosophy must focus on minimizing the power consumption and size, while maintaining sufficient data rate. The desired low-cost and low-power design requires a greatly simplified architecture for the receiver. Power consumption, and minimum operating voltage are the limiting factors for current receiver systems such as direct-conversion or low-IF. The simple architecture of a super-regenerative receiver which can achieve lower power consumption and smaller area is very appealing.
Title:  802.15.4 MAC Layer Standards and Network Layer Implementation on Narada Boards
Graduate Students: Andrew T. Zimmerman (CEE), Arman C. Kizilkale (EECS) Funding Source: Gift Funds Other Investigators: Mingyan Liu (EECS)	Faculty Advisor: Jerome Peter Lynch (EECS/CEE) Work Began: 04/01/2005
Project Goals:
This study seeks to introduce a sophisticated network media access protocol (MAC) to improve the scalability of wireless sensor networks. Apart from this standard implementation, this project also aims to build upper layers to facilitate implementation in actual communication devices. In particular, this implementation will integrate an IEEE802.15.4 wireless transceiver with the Narada wireless sensing unit, which is currently being designed in a parallel WIMS center project. The 802.15.4 wireless standard is selected because it is inherently flexible for ad-hoc network topology formulation and it is an emerging wireless sensor network standard that implies inter-operability with other wireless sensor platforms. Additionally, 802.15.4 is not application specific, which allows it to be used for a wide variety of applications in almost any engineering discipline.
Title:  Design of an 802.15.4-Based Wireless Sensor for Monitoring and Control of Civil Structures
Graduate Students: Raymond A. Swartz (CEE) Funding Source: Gift Funds	Faculty Advisor: Jerome Peter Lynch (EECS/CEE) Work Began: 04/01/2005
Project Goals:
In response to the technical challenges encountered during field instrumentation of wireless sensors in civil structures, this study seeks to improve the power efficiency of wireless sensing units for structural monitoring and control. In addition to improving unit power efficiency, the study will simultaneously introduce a sophisticated network media access protocol (MAC) to improve the scalability of wireless sensor networks installed in large-scale civil structures. In particular, the study integrates an IEEE802.15.4 wireless transceiver with the wireless sensing unit design. The 802.15.4 wireless standard is selected for three reasons: 1) it provides the most energy-efficient communication standard commercially available; 2) is inherently flexible for ad-hoc network topology formulation; and 3) is an emerging wireless sensor network standard that implies inter-operability with other wireless sensor platforms. This study also seeks to explore novel approaches for distributed dynamic control of civil structures utilizing the wireless communication channels in an efficient, power-aware manner. This is achieved by intelligently leveraging the onboard computational power of the wireless sensing units, minimizing power intensive sensor to sensor communication. To issue actuation commands to control actuators, a two-channel actuation interface is included in the wireless sensor design.
Title:  Self-Calibrating Moderate Resolution Analog-to-Digital Converters
Graduate Students: Andres A. Tamez (EECS), Joshua Kang (EECS) Funding Source: GEM Fellowship, Analog Devices, WIMS	Faculty Advisor: Michael P Flynn (EECS) Work Began: 05/01/2004
Project Goals:
The accuracy of SAR analog-to-digital converters is deteriorated by mismatch in the DAC capacitor array. For a 10-bit converter, the array consists of 210(1024) capacitors. Our goal is to identify an optimization algorithm that can be implemented on-chip to calibrate the capacitor array to yield the best ADC performance. The technique will be extended to at 12-bit ADC.
Title:  Lightweight Bidirectional Wireless Neural Recording and Control Microsystem
Graduate Students: Ashkan Borna (EECS), Amir Borna (EECS) Funding Source: NIH	Faculty Advisor: Khalil Najafi (EECS) Work Began: 01/01/2006
Project Goals:
Recent advances in neuroscience have been brought about by advances in many field of science and engineering, including integrated circuit and MEMS, advanced mathematical concepts, signal processing, statistics, and of course improved understanding of biological structures and functions. The primary goal of this project is to collect biological information from freely flying songbirds, and specifically in the Zebra Finch. To understand the role of experience in modifying the brain, songbirds are one of the best models to study. In most of songbirds, the male specie can learn his father's song by a process of imitation which is independent of genetic ties between the birds (S. Overduin, 2003). Also the fact that song learning in birds and language learning in humans both rely on auditory feedback, the study of birdsong learning will lead to knowledge of vocal development in humans. To collect this information extra-cellular neural activity recorded by electrodes implanted in the host’s forebrain, should be processed and then transmitted out over a wireless link to a remote receiver wirelessly. Multichannel neural recording/stimulation systems together with low-power and lightweight wireless communication systems are indeed needed in many emerging applications, including remote sensing, sensor networks, and monitoring of biological signals in freely moving subjects. Tracking of biological or health signals in either animals or humans is of great interest for both research and health care. Scientists have long used biotelemetry for tracking wildlife and in some instances for monitoring the health of wildlife. Tracking of health signals in patients in their living environment is also of great interest to reduce cost and simplify health care delivery.