Bio


Ada was born and raised in Hong Kong. She received her B.Eng degree from the EEE department at the University of Hong Kong and her Ph.D. degree from the EECS department at the University of California at Berkeley in 2004. Her dissertation attempted to connect information theory with electromagnetic theory so as to better understand the fundamental limit of wireless channels

Upon graduation, she spent one year at Intel as a senior research scientist building reconfigurable baseband processors for flexible radios. Afterwards, she joined her advisor’s startup company, SiBeam Inc., architecting Gigabit wireless transceivers leveraging 60 GHz CMOS and MIMO antenna systems. After two years in industries, she returned to academic and joined the faculty of the ECE department at the University of Illinois, Urbana-Champaign. Since then, she has changed her research direction from wireless communications to integrated biomedical systems. In 2008, she moved back to California and joined the faculty of the Department of Electrical Engineering at Stanford University. She is a Terman Fellow at Stanford University. She received the Okawa Foundation Research Grant in 2010 and NSF CAREER Award in 2013.

Academic Appointments


Professional Education


  • PhD, UC Berkeley, Electrical Engineering (2004)
  • BEng, University of Hong Kong, Electrical Engineering (1996)

Current Research and Scholarly Interests


Our research focuses on providing theoretical foundations and engineering platforms for realizing electronics that seamlessly integrate with the body. Such systems will allow precise recording or modulation of physiological activity, for advancing basic scientific discovery and for restoring or augmenting biological functions for clinical applications. To build these integrated biomedical systems, our research program emphasizes a vertical integration of diverse fields ranging from physics, wireless technologies, and low-power integrated circuits. In close collaboration with biologists and clinical specialists, we validate our systems in animal models and prepare the testing of the systems in humans.

Projects


  • Development of Wireless Powered Miniature Pacing Devices for Cardiac Rhythm Management (無線微型心臟起搏器的研發與應用)

    While advances in miniaturization has paved way for tiny cardiac implantable electronic devices (CIEDs) that circumvent conventional surgical implantation, there is still lack of effective method for powering them deep in the body. Existing methods for energy storage, harvesting, or transfer, such as ultrasound or electromagnetic energy require large components that do not scale to millimeter dimensions. At Stanford University, we report a new wireless power transfer method that overcomes this challenge and use it to realize a tiny electrostimulator that is orders of magnitude smaller than conventional pacemakers. The objective of this project is to perform pre-clinical studies in Hong Kong evaluating this new way of powering cardiac pacemaker. This project is funded by ITF, the Government of the Hong Kong Special Administrative Region.

    Location

    Hong Kong

Journal Articles


  • Wireless power transfer to deep-tissue microimplants PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Ho, J. S., Yeh, A. J., Neofytou, E., Kim, S., Tanabe, Y., Patlolla, B., Beygui, R. E., Poon, A. S. 2014; 111 (22): 7974-7979

    Abstract

    The ability to implant electronic systems in the human body has led to many medical advances. Progress in semiconductor technology paved the way for devices at the scale of a millimeter or less ("microimplants"), but the miniaturization of the power source remains challenging. Although wireless powering has been demonstrated, energy transfer beyond superficial depths in tissue has so far been limited by large coils (at least a centimeter in diameter) unsuitable for a microimplant. Here, we show that this limitation can be overcome by a method, termed midfield powering, to create a high-energy density region deep in tissue inside of which the power-harvesting structure can be made extremely small. Unlike conventional near-field (inductively coupled) coils, for which coupling is limited by exponential field decay, a patterned metal plate is used to induce spatially confined and adaptive energy transport through propagating modes in tissue. We use this method to power a microimplant (2 mm, 70 mg) capable of closed-chest wireless control of the heart that is orders of magnitude smaller than conventional pacemakers. With exposure levels below human safety thresholds, milliwatt levels of power can be transferred to a deep-tissue (>5 cm) microimplant for both complex electronic function and physiological stimulation. The approach developed here should enable new generations of implantable systems that can be integrated into the body at minimal cost and risk.

    View details for DOI 10.1073/pnas.1403002111

    View details for Web of Science ID 000336687900037

  • Energy Transfer for Implantable Electronics in the Electromagnetic Midfield PROGRESS IN ELECTROMAGNETICS RESEARCH-PIER Ho, J. S., Poon, A. S. 2014; 148: 151-158
  • A General Solution to Wireless Power Transfer between Two Circular Loops PROGRESS IN ELECTROMAGNETICS RESEARCH-PIER Poon, A. S. 2014; 148: 171-182
  • A Small Dual-Band Asymmetric Dipole Antenna for 13.56 MHz Power and 2.45 GHz Data Transmission IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS Tanabe, Y., Chang, T., Yeh, A. J., Poon, A. S. 2014; 13: 1120-1123
  • Wirelessly powering miniature implants for optogenetic stimulation APPLIED PHYSICS LETTERS Yeh, A. J., Ho, J. S., Tanabe, Y., Neofytou, E., Beygui, R. E., Poon, A. S. 2013; 103 (16)

    View details for DOI 10.1063/1.4825272

    View details for Web of Science ID 000326148700092

  • Mass fabrication and delivery of 3D multilayer mu Tags into living cells SCIENTIFIC REPORTS Chen, L. Y., Parizi, K. B., Kosuge, H., Milaninia, K. M., McConnell, M. V., Wong, H. P., Poon, A. S. 2013; 3

    View details for DOI 10.1038/srep02295

    View details for Web of Science ID 000322308900002

  • Midfield Wireless Powering for Implantable Systems PROCEEDINGS OF THE IEEE Ho, J. S., Kim, S., Poon, A. S. 2013; 101 (6): 1369-1378
  • Midfield Wireless Powering of Subwavelength Autonomous Devices PHYSICAL REVIEW LETTERS Kim, S., Ho, J. S., Poon, A. S. 2013; 110 (20)
  • Mass fabrication and delivery of 3D multilayer µTags into living cells. Scientific reports Chen, L. Y., Parizi, K. B., Kosuge, H., Milaninia, K. M., McConnell, M. V., Wong, H. P., Poon, A. S. 2013; 3: 2295-?

    Abstract

    Continuous monitoring of in vivo biological processes and their evolution at the cellular level would enable major advances in our understanding of biology and disease. As a stepping stone towards chronic cellular monitoring, we demonstrate massively parallel fabrication and delivery of 3D multilayer micro-Tags (μTags) into living cells. Both 10 μm × 10 μm × 1.5 μm and 18 μm × 7 μm × 1.5 μm devices containing inductive and capacitive structures were designed and fabricated as potential passive radio-frequency identification tags. We show cellular internalization and persistence of μTags over a 5-day period. Our results represent a promising advance in technologies for studying biology and disease at the cellular level.

    View details for DOI 10.1038/srep02295

    View details for PubMedID 23887586

  • Emerging wireless applications in biomedicine 2013 5TH IEEE INTERNATIONAL WORKSHOP ON ADVANCES IN SENSORS AND INTERFACES (IWASI) Poon, A. 2013: 35-35
  • A mm-Sized Wirelessly Powered and Remotely Controlled Locomotive Implant IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS Pivonka, D., Yakovlev, A., Poon, A. S., Meng, T. 2012; 6 (6): 523-532
  • Wireless Power Transfer to Miniature Implants: Transmitter Optimization IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION Kim, S., Ho, J. S., Poon, A. S. 2012; 60 (10): 4838-4845
  • Wireless power transfer to a cardiac implant APPLIED PHYSICS LETTERS Kim, S., Ho, J. S., Chen, L. Y., Poon, A. S. 2012; 101 (7)

    View details for DOI 10.1063/1.4745600

    View details for Web of Science ID 000308263100081

  • Supporting and Enabling Circuits for Antenna Arrays in Wireless Communications PROCEEDINGS OF THE IEEE Poon, A. S., Taghivand, M. 2012; 100 (7): 2207-2218
  • Implantable Biomedical Devices: Wireless Powering and Communication IEEE COMMUNICATIONS MAGAZINE Yakovlev, A., Kim, S., Poon, A. 2012; 50 (4): 152-159
  • Exceeding Nernst Limit (59mV/pH): CMOS-Based pH Sensor for Autonomous Applications 2012 IEEE INTERNATIONAL ELECTRON DEVICES MEETING (IEDM) Parizi, K. B., Yeh, A. J., Poon, A. S., Wong, H. S. 2012
  • A mm-sized wireless powered and remotely controlled locomotive implant IEEE Trans. Biomedical Circuits and Systems Pivonka, D., Yakovlev, A., Poon, A., Meng, T. 2012; 6 (6): 523-532
  • Wireless Powering of Microchip Implants by a Cross-Slot Antenna 2012 ASIA-PACIFIC MICROWAVE CONFERENCE (APMC 2012) Tanabe, Y., Ho, J. S., Wong, H., Poon, A. S. 2012: 418-420
  • Degree-of-Freedom Gain From Using Polarimetric Antenna Elements IEEE TRANSACTIONS ON INFORMATION THEORY Poon, A. S., Tse, D. N. 2011; 57 (9): 5695-5709
  • Detecting Human Blockage and Device Movement in mmWave Communication System 2011 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE (GLOBECOM 2011) Tsang, Y. M., Poon, A. S. 2011
  • Wireless communication device using adaptive beamforming Poon, A., S. Y. 2011
  • Coding the Beams: Improving Beamforming Training in mmWave Communication System 2011 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE (GLOBECOM 2011) Tsang, Y. M., Poon, A. S., Addepalli, S. 2011
  • Optimal Transmit Dimension for Wireless Powering of Miniature Implants 2011 IEEE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (APSURSI) Kim, S., Poon, A. S. 2011: 408-411
  • Optimal Frequency for Wireless Power Transmission Into Dispersive Tissue IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION Poon, A. S., O'Driscoll, S., Meng, T. H. 2010; 58 (5): 1739-1750
  • Optimizations of Source Distribution in Wireless Power Transmission for Implantable Devices 2010 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM Kim, S., Poon, A. S. 2010
  • Translating Electromagnetic Torque into Controlled Motion for use in Medical Implants 2010 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC) Pivonka, D., Meng, T., Poon, A. 2010: 6433-6436

    Abstract

    A new propulsion method for sub-millimeter implants is presented that achieves high power to thrust conversion efficiency with a simple implementation. Previous research has shown that electromagnetic forces are a promising micro-scale propulsion mechanism; however the actual implementation is challenging due to the inherent symmetry of these forces. The presented technique translates torque into controlled motion via asymmetries in resistance forces, such as fluid drag. For a 1-mm sized object using this technique, the initial analysis predicts that speeds of 1 cm/sec can be achieved with approximately 100 µW of power, which is about 10 times more efficient than existing methods. In addition to better performance, this method is easily controllable and has favorable scalability.

    View details for Web of Science ID 000287964006208

    View details for PubMedID 21096711

  • Degree-of-Freedom Gain from Polarimetric Antenna Elements 2010 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM Poon, A. S. 2010
  • Locomotive Micro-Implant with Active Electromagnetic Propulsion 2009 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-20 Pivonka, D., Poon, A. S., Meng, T. H. 2009: 6404-6407

    Abstract

    An active locomotive technique requiring only an external power source and a static magnetic field is presented, and its operation is analyzed and simulated. For a modest static MRI magnetic field of 1 T, the results show that a 1-mm cube achieves roughly 3 cm/sec of lateral motion using less than 20.4 microW of power. Current-carrying wires generate the forces, resulting in highly controllable motion. Existing solutions trade off size and power: passive solutions are small but impractical, and mechanical solutions are inefficient and large. The presented solution captures the advantages of both systems, and has much better scalability.

    View details for Web of Science ID 000280543605057

    View details for PubMedID 19964695

  • Miniaturization of Implantable Wireless Power Receiver 2009 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-20 Poon, A. S. 2009: 3217-3220

    Abstract

    Implantable medical devices will play an important role in modern medicine. To reduce the risk of wire snapping, and replacement and corrosion of embedded batteries, wireless delivery of energy to these devices is desirable. However, current autonomous implants remain large in scale due to the operation at very low frequency and the use of unwieldy size of antennas. This paper will show that the optimal frequency is about 2 orders of magnitude higher than the conventional wisdom; and thereby the power receiving coils can be reduced by more than 100 fold without sacrificing either power efficiency or range. We will show that a mm-sized implant can receive 100's microW of power under safety constraints. This level of power transfer is sufficient to enable many functionalities into the micro-implants for clinical applications.

    View details for Web of Science ID 000280543602168

    View details for PubMedID 19964059

  • A mixed-signal vector modulator for eigen-beamforming receivers IEEE Trans. Circuits and Systems II Tseng, R., Poon, A., S. Y., Chiu, Y. 2008; 55 (5): 479–483
  • Optimal operating frequency in wireless power transmission for implantable devices 2007 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-16 Poon, A. S., O'Driscoll, S., Meng, T. H. 2007: 5674-5679

    Abstract

    This paper examines short-range wireless powering for implantable devices and shows that existing analysis techniques are not adequate to conclude the characteristics of power transfer efficiency over a wide frequency range. It shows, theoretically and experimentally, that the optimal frequency for power transmission in biological media can be in the GHz-range while existing solutions exclusively focus on the MHz-range. This implies that the size of the receive coil can be reduced by 10(4) times which enables the realization of fully integrated implantable devices.

    View details for Web of Science ID 000253467004156

    View details for PubMedID 18003300

  • An energy-efficient reconfigurable baseband processor for wireless communications IEEE Trans. VLSI Systems Poon, A., S. Y. 2007; 15 (3): 319–327
  • Angular domain signal processing techniques Poon, A., S. Y. 2007
  • Deterministic spatial power allocation and bit loading for closed loop MIMO Poon, A., S. Y. 2006
  • Technique to increase a code rate in a MIMO system using virtual channels Poon, A., S. Y. 2006
  • Method and system for closed loop transmit beamforming in MIMO systems with limited feedback Poon, A., S. Y. 2006
  • Link adaptation for MIMO transmission schemes Poon, A., S. Y. 2006
  • Impact of scattering on the capacity, diversity, and propagation range of multiple-antenna channels IEEE Trans. Information Theory Poon, A., S. Y., Tse, D., N. C., Brodersen, R., W. 2006; 52 (3): 1087–1100
  • Determining spatial power allocation and bit loading for a MIMO OFDM system without feedback information about the channel Poon, A., S. Y. 2006
  • Code rate adaptation in a MIMO system using virtual channels Poon, A., S. Y. 2006
  • Closed loop MIMO systems using codebooks for feedback Poon, A., S. Y. 2006
  • Closed loop feedback in MIMO systems Poon, A., S. Y. 2006
  • Bit distributor for multicarrier communication systems employing adaptive bit loading for multiple spatial streams and methods Poon, A., S. Y. 2006
  • Apparatus and method to form a transform Poon, A., S. Y. 2006
  • Adaptive bit loading for multicarrier communication system Poon, A., S. Y. 2006
  • Spatial puncturing apparatus, method, and system Poon, A., S. Y. 2005
  • Degrees of freedom in multiple-antenna channels: a signal space approach IEEE Trans. Information Theory Poon, A., S. Y., Brodersen, R., W., Tse, D., N. C. 2005; 51 (2): 523–536
  • Compact feedback for closed loop MIMO systems Poon, A., S. Y. 2005
  • An adaptive multi-antenna transceiver for slowly flat-fading channels IEEE Trans. Communications Poon, A., S. Y., Tse, D., N. C., Brodersen, R., W. 2003; 51 (11): 1820–1827
  • Game theoretical multi-agent modelling of coalition formation for multilateral trades IEEE TRANSACTIONS ON POWER SYSTEMS Yeung, C. S., Poon, A. S., Wu, F. F. 1999; 14 (3): 929-934

Conference Proceedings


  • Electromagnetic field focusing for short-range wireless power transmission Poon, A., S. Y. 2012
  • Beam focused slot antenna for microstrip implants Tanabe, Y., Wong, H., Kim, S., Ho, J., S., Poon, A., S. Y. 2012
  • Successive AoA estimation: revealing the second path for 60 GHz communication system Tsang, Y., M., Poon, A., S. Y. 2011
  • Future implantable systems Poon, A., S. Y. 2011
  • A 60GHz digitally controlled RF beamforming array in 65nm CMOS with off-chip antennas Lin, S., Ng, K., B., Wong, H., Luk, L., M., Wong, S., S., Poon, A., S. Y. 2011
  • A Four-Channel Beamforming Down-Converter in 90-nm CMOS Utilizing Phase-Oversampling Tseng, R., Li, H., Kwon, D. H., Chiu, Y., Poon, A. S. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. 2010: 2262-2272
  • Fast beam training for mmWave communication system: from algorithm to circuits Tsang, Y., M., Lin, S., Poon, A., S. Y. 2010
  • An inherently linear phase-oversampling vector modulator in 90-nm CMOS Tseng, R., Li, H., Kwon, D., H., Poon, A., S. Y., Chiu, Y. 2009
  • A mm-sized implantable power receiver with adaptive link compensation O’Driscoll, S., Poon, A., S. Y., Meng, T., H. 2009
  • A mm-sized implantable wireless power receiver Poon, A., S. Y. 2009
  • Polarization degrees of freedom Poon, A., S. Y., Tse, D., N. C. 2008
  • Non-robustness of statistics-based beamformer design in correlated design in correlated MIMO channels Raghavan, V., Poon, A., Veeravalli, V. 2008
  • Angular domain processing for MIMO wireless systems with non-uniform antenna arrays Huang, D., Raghavan, V., Poon, A., Veeravalli, V. 2008
  • A mixed-signal MIMO beamforming receiver Tseng, R., Poon, A., S. Y., Chiu, Y. 2008
  • MIMO systems with arbitrary antenna array architectures: channel modeling, capacity, and low-complexity signaling Raghavan, V., Poon, A., Veeravalli, V. 2007
  • An energy-efficient reconfigurable baseband processor for flexible radios Poon, A., S. Y. 2006
  • Spatial channel models for multiple-antenna systems Poon, A., S. Y., Tse, D., N. C., Brodersen, R., W. 2004
  • Indoor multiple-antenna channel characterization from 2 to 8 GHz Poon, A., S. Y., Ho, M. 2003
  • Multiple-antenna channels from a combined physical and networking perspective Poon, A., S. Y., Tse, D., N. C., Brodersen, R., W. 2002
  • The signal dimensions in multiple-antenna channels Poon, A., S. Y., Tse, D., N. C., Brodersen, R., W. 2002
  • Trade-offs of performance and single chip implementation of indoor wireless multi-access receivers Zhang, N., Poon, A., S. Y., Tse, D., N. C., Brodersen, R., W., Verdu, S. 1999
  • A multi-agent approach to the deregulation and restructuring of power industry Poon, A., S. Y., Wu, F., F., Yeung, C., S. K., Yen, J. 1998