Publications

Towards a Synthesizable Standard-Cell Radio

Richard Su
Kristofer S.J. Pister
Jan Rabaey
Paul Wright
2011

Radios available today are designed to be high performance devices. These radios require careful design by experienced and skilled RF IC designers, more expensive RF processes, and large chip areas for RF passives. The resulting cost of these devices is at the dollar level without the off chip components, and the careful design required makes integration of these radios with other circuits (microprocessors, sensors, etc) an expensive proposition. We believe that radios that require limited design skills while still having good performance will enable widespread use of wireless...

High-Q Low-Impedance MEMS Resonators

Li-Wen Hung
Clark T.-C. Nguyen
Tsu-Jae King Liu
Liwei Lin
2012

The ever increasing need for regional and global roaming together with continuous advances in wireless communication standards continue to push future transceivers towards an ability to support multi-mode operation with minimal increases in cost, hardware complexity, and power consumption. RF channel-select filter banks pose a particularly attractive method for achieving multiband reconfigurability, since they not only provide the needed front-end reconfigurability, but also allow for power efficient and versatile transceiver designs, e.g., software-defined radio. Such channel-select...

Atomically Thin Processing of High Surface Area Nanomaterials for Electrochemical Energy Devices

Emmeline Kao
Liwei Lin
Hayden Taylor
Dorian Liepmann
2018

As interest in renewable energy grows on both research and policy fronts, energy storage likely represents one of the most viable solutions to the problems posed by the intermittency and irregularity of renewable resources. While new classes of materials promise improved performance of energy storage systems, understanding energy storage electrode architecture and fabrication at the micro-scale allows us to fully leverage performance along different dimensions.

This dissertation aims to explore the...

Solid-Liquid Interdiffusion Bonding of Silicon Carbide to Steel for High Temperature MEMS Sensor Packaging and Bonding

Matthew Chan
Albert P. Pisano
Liwei Lin
Junqiao Wu
2013

Complex engineering systems ranging from automobile engines to geothermal wells require specialized sensors to monitor conditions such as pressure, acceleration and temperature in order to improve efficiency and monitor component lifetime in what may be high temperature, corrosive, harsh environments. Microelectromechanical systems (MEMS) have demonstrated their ability to precisely and accurately take measurements under such conditions. The systems being monitored are typically made from metals, such as steel, while...

Feasibility, Design, and Optimization of a Torsionally-Actuated Microgimbal Using the Polystrata® Process

Chris McCoy
Albert P. Pisano
Dennis K. Lau
2009

MicroGimbals provide a unique solution to image stabilization system for micro air vehicles (MAVs). The MicroGimbal is a Microelectromechanical System (MEMS) device designed for military officials and doctors who need the ability to control the position, stability and attitude of micro-scale imaging devices in otherwise harsh environments. The MicroGimbal uses electrostatic actuation to achieve controlled angular deflection along two axes. Unlike standard...

High Resolution Additive Patterning of Nanoparticles and Polymers Enabled by Vapor Permeable Polymer Templates

Michael Demko
Alberto P. Pisano
Liwei Lin
Ming C. Wu
2012
The structure and chemistry of nanoparticles and polymers are interesting for applications in electronics and sensors. However, because they are outside of the standard material set typically used for these applications, widespread use of these materials has not yet been realized. This is due in part to the limited ability of traditional manufacturing processes to adapt to these unique materials. As a result, several alternative manufacturing methods have been developed, including nanoimprint lithography,...

Actuated Mobile Sensing in Distributed, Unstructured Environments

Andrew Tinka
Kristofer S.J. Pister
2012

Mobile sensor networks present opportunities for improved in situ sensing in complex hydrodynamic environments such as estuarial deltas. This dissertation considers the design and implementation of the mobile sensor network system that was built as part of the Floating Sensor Network project for use in the Sacramento-San Joaquin Delta in California over the 2007-2012 time period. Individual Lagrangian sensor units collect hydrodynamic state information, which is then transmitted to a centralized server and assimilated to produce a state estimate for the entire hydrodynamic system....

Mobility in Wireless Sensor Networks

Ankur Mehta
Kristofer S.J. Pister
Michel M. Maharbiz
Alexandre Bayen
2012

The combination of mobility with wireless networks greatly expands the application space of both robots and distributed sensor networks; such a pervasive system can enable seamless integration between the digital and physical worlds. However, there are a number of issues in both robotic and wireless sensor network (WSN) fields that demand research, and their integration generates further challenges.

A fundamental open problem in robotic systems is the issue of self-contained localization. Especially difficult when considering small scale flying robots, the ability to determine one'...

Metal-optic and Plasmonic Semiconductor-based Nanolasers

Amit Lakhani
Ming C. Wu
Xiang Zhang
Eli Yablonovitch
2012

Over the past few decades, semiconductor lasers have relentlessly followed the path towards miniaturization. Smaller lasers are more energy efficient, are cheaper to make, and open up new applications in sensing and displays, among many other things. Yet, up until recently, there was a fundamental problem with making lasers smaller: purely semiconductor lasers couldn't be made smaller than the diffraction limit of light.

In recent years, however, metal-based lasers have been demonstrated in the nanoscale that have shattered the diffraction limit. As optical materials, metals can be...

MEMS Lens Scanners for Free-Space Optical Interconnects

Jeffrey Chou
Ming C. Wu
Bernhard E. Boser
Liwei Lin
2011

Optical interconnects are the next evolutionary step for computer server systems, replacing traditional copper interconnects to increase communication bandwidth and reduce overall power consumption. A variety of implementation techniques to bring optics to the rack-to-rack, board-to-board, and chip-to-chip scale are heavily pursued in the research space. In this dissertation we present a micro-electro mechanical systems (MEMS) based free-space optical link for board-to-board interconnects.

As with any free-space optical system, alignment is critical for the correction of undesired...