Bio


Ada received 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.

Administrative Appointments


  • Member, Stanford Diabetes Research Center (2019 - Present)

Honors & Awards


  • CZ Biohub Investigator, Chan Zuckerberg Biohub (2017)
  • CAREER Award, NSF (2013)
  • Research Grant recipient, Okawa Foundation (2010)
  • Terman Fellow, Stanford (2008)

Program Affiliations


  • Stanford SystemX Alliance

Professional Education


  • PhD, UC Berkeley, Electrical Engineering (2004)
  • MS, UC Berkeley, Electrical Engineering (1999)

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


  • Memory recovery device for Alzheimer’s disease and other dementias

    In US, one in 10 people age 65 and older has Alzheimer’s disease (AD). This number increases to one in 3 people age 85 and older. Loss of memory and reasoning badly rob the quality of life and dignity of the elderly. Unfortunately, AD cannot be prevented, cured, or even slowed. Instead of waiting for a pharmaceutical breakthrough, we propose a radical solution to develop a redundant electronic memory system that would progressively replace degenerated neurons and hence reversing effects of neurodegeneration in AD and other dementias.

    Location

    Stanford, CA

  • Wireless neuromodulation platforms, Stanford University

    Optical or electrical stimulation of neural circuits in mice during natural behavior is an important paradigm for studying brain function. Conventional systems for optogenetics and electrical stimulation require tethers or large head-mounted devices that disrupt animal behavior. Our research focuses on developing new wireless tools for activity modulation and recording in both the brain and the periphery. Targeted technologies include wireless platforms for experiments in freely-moving animals and tiny, fully-implantable devices for controlled delivery of light or electrical pulses.

    Location

    Stanford, CA

    Collaborators

    • Scott Delp, James H. Clark Professor in the School of Engineering, Professor of Bioengineering, of Mechanical Engineering and, by courtesy, of Orthopaedic Surgery, Stanford University
    • Karl Deisseroth, Professor, Stanford University
  • Wireless power transfer to microimplants, Stanford University

    Medical electronics are capable of precisely monitoring or modulating activity in the human body, and thus hold promise for treating a broad range of diseases. To implant electronic devices in the body, they need to be miniaturized and powered wirelessly across complex biological tissue. We are developing a new method of electromagnetic energy transfer, termed midfield powering, to power devices at the scale of a millimeter or less anywhere in the body, including the heart and the brain. Our approach spans fundamental studies of wave-tissue interactions, development of new electromagnetic structures, and experiments in both computational and animal tissue models.

    Location

    Stanford, CA

    Collaborators

    • Ramin Beygui, Professor of Cardiothoracic Surgery, Stanford University
  • Low-power biomedical integrated circuits, Stanford University

    Advances in integrated circuit technology have enabled electronic systems that can augment or even replace physiological functions. While the processing capabilities of these devices are virtually unlimited, the available energy is highly constrained. Our research combines low-power architectures with innovations in circuit design techniques to design biomedical electronics capable of ultra-low-power operation in the human body.

    Location

    Stanford University

  • Metasurfaces, Stanford University

    The solid immersion lens is a powerful optical tool that allows light entering material from air or vacuum to focus to a spot much smaller than the free-space wavelength. Conventionally, however, they rely on semispherical topographies and are non-planar and bulky, which limits their integration in many applications. Recently, there has been considerable interest in using planar structures, referred to as metasurfaces, to construct flat optical components for manipulating light in unusual ways. Here, we propose and demonstrate the concept of a planar immersion lens based on metasurfaces. The resulting planar device, when placed near an interface between air and dielectric material, can focus electromagnetic radiation incident from air to a spot in material smaller than the free-space wavelength.

    Location

    Stanford, CA

    Collaborators

    • Shanhui Fan, Professor of Electrical Engineering and, by courtesy, of Applied Physics, Stanford University

Stanford Advisees


All Publications


  • Novel Pathogenic de novo INS p.T97P Variant Presenting with Severe Neonatal DKA. Endocrinology Lal, R. A., Moeller, H. P., Thomson, E. A., Horton, T. M., Lee, S., Freeman, R., Prahalad, P., Poon, A. S., Annes, J. P. 2021

    Abstract

    Pathogenic INS gene mutations are causative for Mutant INS-gene-induced Diabetes of Youth (MIDY). We characterize a novel de novo heterozygous INS gene mutation (c.289A>C, p.T97P) that presented in an autoantibody-negative 5-month-old male infant with severe diabetic ketoacidosis. In silico pathogenicity prediction tools provided contradictory interpretations, while structural modeling indicated a deleterious effect on proinsulin folding. Transfection of wildtype and INS p.T97P expression and luciferase reporter constructs demonstrated elevated intracellular mutant proinsulin levels and dramatically impaired proinsulin/insulin and luciferase secretion. Notably, proteasome inhibition partially and selectively rescued INS p.T97P-derived luciferase secretion. Additionally, expression of INS p.T97P caused increased intracellular proinsulin aggregate formation and XBP-1s protein levels, consistent with induction of endoplasmic reticulum stress. We conclude that INS p.T97P is a newly identified pathogenic A-chain variant that is causative for MIDY via disruption of proinsulin folding and processing with induction of the endoplasmic reticulum stress response.

    View details for DOI 10.1210/endocr/bqab246

    View details for PubMedID 34888628

  • Intracellular detection and communication of a wireless chip in cell. Scientific reports Yang, M. X., Hu, X., Akin, D., Poon, A., Wong, H. P. 2021; 11 (1): 5967

    Abstract

    The rapid growth and development of technology has had significant implications for healthcare, personalized medicine, and our understanding of biology. In this work, we leverage the miniaturization of electronics to realize the first demonstration of wireless detection and communication of an electronic device inside a cell. This is a significant forward step towards a vision of non-invasive, intracellular wireless platforms for single-cell analyses. We demonstrate that a 25 [Formula: see text]m wireless radio frequency identification (RFID) device can not only be taken up by a mammalian cell but can also be detected and specifically identified externally while located intracellularly. The S-parameters and power delivery efficiency of the electronic communication system is quantified before and after immersion in a biological environment; the results show distinct electrical responses for different RFID tags, allowing for classification of cells by examining the electrical output noninvasively. This versatile platform can be adapted for realization of a broad modality of sensors and actuators. This work precedes and facilitates the development of long-term intracellular real-time measurement systems for personalized medicine and furthering our understanding of intrinsic biological behaviors. It helps provide an advanced technique to better assess the long-term evolution of cellular physiology as a result of drug and disease stimuli in a way that is not feasible using current methods.

    View details for DOI 10.1038/s41598-021-85268-5

    View details for PubMedID 33727598

  • Coupling-Independent Real-Time Wireless Resistive Sensing Through Nonlinear PT Symmetry PHYSICAL REVIEW APPLIED Kananian, S., Alexopoulos, G., Poon, A. Y. 2020; 14 (6)
  • Wireless optogenetics protects against obesity via stimulation of non-canonical fat thermogenesis. Nature communications Tajima, K. n., Ikeda, K. n., Tanabe, Y. n., Thomson, E. A., Yoneshiro, T. n., Oguri, Y. n., Ferro, M. D., Poon, A. S., Kajimura, S. n. 2020; 11 (1): 1730

    Abstract

    Cold stimuli and the subsequent activation of β-adrenergic receptor (β-AR) potently stimulate adipose tissue thermogenesis and increase whole-body energy expenditure. However, systemic activation of the β3-AR pathway inevitably increases blood pressure, a significant risk factor for cardiovascular disease, and, thus, limits its application for the treatment of obesity. To activate fat thermogenesis under tight spatiotemporal control without external stimuli, here, we report an implantable wireless optogenetic device that bypasses the β-AR pathway and triggers Ca2+ cycling selectively in adipocytes. The wireless optogenetics stimulation in the subcutaneous adipose tissue potently activates Ca2+ cycling fat thermogenesis and increases whole-body energy expenditure without cold stimuli. Significantly, the light-induced fat thermogenesis was sufficient to protect mice from diet-induced body-weight gain. The present study provides the first proof-of-concept that fat-specific cold mimetics via activating non-canonical thermogenesis protect against obesity.

    View details for DOI 10.1038/s41467-020-15589-y

    View details for PubMedID 32265443

  • Optimization of Sine-Wave Clocking for High-Frequency AC-DC Conversion. IEEE transactions on power electronics Hsu, S., Poon, A. S. 2019; 34 (1): 391-402

    Abstract

    Wireless energy harvesting devices convert received AC energy into DC voltages suitable to power the back-end functionality of the devices. The low energy available to the devices require high AC-DC conversion efficiency in order for enough power to be delivered to the load. This paper presents a model to characterize loss through charge pump cells in wireless energy harvesting devices. The proposed model includes the time-domain effects of the input radio-frequency (RF) energy wave and provides additional insight into how clock and switch parameters along with architecture considerations can be used to improve the efficiency of AC-DC conversion. Results are verified using simulation in a 0.18-μm CMOS technology. We show the impact of threshold voltage on reverse conduction and the limitations on increasing transistor switch sizes to support high current loads. Design examples use the presented model to optimize design parameters to decrease loss in the charge pump. We compare the performance between sine-wave and square-wave clocked charge pumps to show the trade-off between charge pump loss and clock generation power consumption. Furthermore, the benefits of easily computing architectural changes is demonstrated using the proposed model showing how the calculated equivalent resistance can be used to determine the benefits of mixed-mode clocking.

    View details for DOI 10.1109/tpel.2018.2815627

    View details for PubMedID 32863572

    View details for PubMedCentralID PMC7453883

  • An RF-Powered FDD Radio for Neural Microimplants IEEE JOURNAL OF SOLID-STATE CIRCUITS Rajavi, Y., Taghivand, M., Aggarwal, K., Ma, A., Poon, A. S. 2017; 52 (5): 1221-1229
  • A Millimeter-Wave Digital Link for Wireless MRI IEEE TRANSACTIONS ON MEDICAL IMAGING Aggarwal, K., Joshi, K. R., Rajavi, Y., Taghivand, M., Pauly, J. M., Poon, A. S., Scott, G. 2017; 36 (2): 574-583

    Abstract

    A millimeter (mm) wave radio is presented in this work to support wireless MRI data transmission. High path loss and availability of wide bandwidth make mm-waves an ideal candidate for short range, high data rata communication required for wireless MRI. The proposed system uses a custom designed integrated chip (IC) mm-wave radio with 60 GHz as radio frequency carrier. In this work, we assess performance in a 1.5 T MRI field, with the addition of optical links between the console room and magnet. The system uses ON-OFF keying (OOK) modulation for data transmission and supports data rates from 200 Mb/s to 2.5 Gb/s for distances up-to 65 cm. The presence of highly directional, linearly polarized, on-chip dipole antennas on the mm-wave radio along with the time division multiplexing (TDM) circuitry allows multiple wireless links to be created simultaneously with minimal inter-channel interference. This leads to a highly scalable solution for wireless MRI.

    View details for DOI 10.1109/TMI.2016.2622251

    View details for Web of Science ID 000396115800021

    View details for PubMedCentralID PMC5709036

  • High-performance wireless powering for peripheral nerve neuromodulation systems. PloS one Tanabe, Y. n., Ho, J. S., Liu, J. n., Liao, S. Y., Zhen, Z. n., Hsu, S. n., Shuto, C. n., Zhu, Z. Y., Ma, A. n., Vassos, C. n., Chen, P. n., Tse, H. F., Poon, A. S. 2017; 12 (10): e0186698

    Abstract

    Neuromodulation of peripheral nerves with bioelectronic devices is a promising approach for treating a wide range of disorders. Wireless powering could enable long-term operation of these devices, but achieving high performance for miniaturized and deeply placed devices remains a technological challenge. We report the miniaturized integration of a wireless powering system in soft neuromodulation device (15 mm length, 2.7 mm diameter) and demonstrate high performance (about 10%) during in vivo wireless stimulation of the vagus nerve in a porcine animal model. The increased performance is enabled by the generation of a focused and circularly polarized field that enhances efficiency and provides immunity to polarization misalignment. These performance characteristics establish the clinical potential of wireless powering for emerging therapies based on neuromodulation.

    View details for PubMedID 29065141

    View details for PubMedCentralID PMC5655495

  • Micrometer-scale magnetic-resonance-coupled radio-frequency identification and transceivers for wireless sensors in cells Physical Review Applied Hu, X., Aggarwal, K., Yang, M., Parizi, K., Xu, X., Akin, D., Poon, A., Wong, H. 2017
  • Conformal phased surfaces for wireless powering of bioelectronic microdevices. Nature biomedical engineering Agrawal, D. R., Tanabe, Y. n., Weng, D. n., Ma, A. n., Hsu, S. n., Liao, S. Y., Zhen, Z. n., Zhu, Z. Y., Sun, C. n., Dong, Z. n., Yang, F. n., Tse, H. F., Poon, A. S., Ho, J. S. 2017; 1

    Abstract

    Wireless powering could enable the long-term operation of advanced bioelectronic devices within the human body. Although both enhanced powering depth and device miniaturization can be achieved by shaping the field pattern within the body, existing electromagnetic structures do not provide the spatial phase control required to synthesize such patterns. Here, we describe the design and operation of conformal electromagnetic structures, termed phased surfaces, that interface with non-planar body surfaces and optimally modulate the phase response to enhance the performance of wireless powering. We demonstrate that the phased surfaces can wirelessly transfer energy across anatomically heterogeneous tissues in large animal models, powering miniaturized semiconductor devices (<12 mm3) deep within the body (>4 cm). As an illustration ofin vivooperation, we wirelessly regulated cardiac rhythm by powering miniaturized stimulators at multiple endocardial sites in a porcine animal model.

    View details for PubMedID 29226018

    View details for PubMedCentralID PMC5722470

  • A NEW KIND OF WIRELESS MOUSE IEEE SPECTRUM Poon, A. 2016; 53 (12): 26-U37
  • Wirelessly powered, fully internal optogenetics for brain, spinal and peripheral circuits in mice. Nature methods Montgomery, K. L., Yeh, A. J., Ho, J. S., Tsao, V., Mohan Iyer, S., Grosenick, L., Ferenczi, E. A., Tanabe, Y., Deisseroth, K., Delp, S. L., Poon, A. S. 2015; 12 (10): 969-974

    Abstract

    To enable sophisticated optogenetic manipulation of neural circuits throughout the nervous system with limited disruption of animal behavior, light-delivery systems beyond fiber optic tethering and large, head-mounted wireless receivers are desirable. We report the development of an easy-to-construct, implantable wireless optogenetic device. Our smallest version (20 mg, 10 mm(3)) is two orders of magnitude smaller than previously reported wireless optogenetic systems, allowing the entire device to be implanted subcutaneously. With a radio-frequency (RF) power source and controller, this implant produces sufficient light power for optogenetic stimulation with minimal tissue heating (<1 °C). We show how three adaptations of the implant allow for untethered optogenetic control throughout the nervous system (brain, spinal cord and peripheral nerve endings) of behaving mice. This technology opens the door for optogenetic experiments in which animals are able to behave naturally with optogenetic manipulation of both central and peripheral targets.

    View details for DOI 10.1038/nmeth.3536

    View details for PubMedID 26280330

  • Self-Tracking Energy Transfer for Neural Stimulation in Untethered Mice PHYSICAL REVIEW APPLIED Ho, J. S., Tanabe, Y., Iyer, S. M., Christensen, A. J., Grosenick, L., Deisseroth, K., Delp, S. L., Poon, A. S. 2015; 4 (2)
  • An Energy Harvesting 2 x 2 60 GHz Transceiver With Scalable Data Rate of 38-2450 Mb/s for Near-Range Communication IEEE JOURNAL OF SOLID-STATE CIRCUITS Taghivand, M., Aggarwal, K., Rajavi, Y., Poon, A. S. 2015; 50 (8): 1889-1902
  • Planar immersion lens with metasurfaces PHYSICAL REVIEW B Ho, J. S., Qiu, B., Tanabe, Y., Yeh, A. J., Fan, S., Poon, A. S. 2015; 91 (12)
  • Midfield Wireless Power Transfer for Bioelectronics IEEE CIRCUITS AND SYSTEMS MAGAZINE Ma, A., Poon, A. S. 2015; 15 (2): 54-60
  • 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

    View details for PubMedID 24843161

    View details for PubMedCentralID PMC4050616

  • 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

  • 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)

    Abstract

    We obtain an analytical bound on the efficiency of wireless power transfer to a weakly coupled device. The optimal source is solved for a multilayer geometry in terms of a representation based on the field equivalence principle. The theory reveals that optimal power transfer exploits the properties of the midfield to achieve efficiencies far greater than conventional coil-based designs. As a physical realization of the source, we present a slot array structure whose performance closely approaches the theoretical bound.

    View details for DOI 10.1103/PhysRevLett.110.203905

    View details for Web of Science ID 000319214800003

  • 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
  • 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
  • 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
  • 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
  • Ultimate performance of microwave tissue ablation PHYSICAL REVIEW APPLIED Lee, S., Lee, J., Poon, A. Y., Kim, S. 2024; 22 (1)
  • Enhancing Therapeutic Insulin Transport from Macroencapsulated Islets Using Sub-Minute Pressure at Physiological Levels. bioRxiv : the preprint server for biology Thomson, E. A., Lee, S., Xu, H., Moeller, H., Sands, J., Lal, R. A., Annes, J. P., Poon, A. S. 2024

    Abstract

    Cadaveric islet and stem cell-derived transplantations hold promise as treatments for type 1 diabetes. To tackle the issue of immunocompatibility, numerous cellular macroencapsulation techniques have been developed that utilize diffusion to transport insulin across an immunoisolating barrier. However, despite several devices progressing to human clinical trials, none have successfully managed to attain physiologic glucose control or insulin independence. Based on empirical evidence, macroencapsulation methods with multilayered, high islet surface density are incompatible with homeostatic, on-demand insulin delivery and physiologic glucose regulation, when reliant solely on diffusion. An additional driving force is essential to overcome the distance limit of diffusion. In this study, we present both theoretical proof and experimental validation that applying pressure at levels comparable to physiological diastolic blood pressure significantly enhances insulin flux across immunoisolation membranes-increasing it by nearly three orders of magnitude. This significant enhancement in transport rate allows for precise, sub-minute regulation of both bolus and basal insulin delivery. By incorporating this technique with a pump-based extravascular system, we demonstrate the ability to rapidly reduce glucose levels in diabetic rodent models, effectively replicating the timescale and therapeutic effect of subcutaneous insulin injection or infusion. This advance provides a potential path towards achieving insulin independence with islet macroencapsulation.One Sentence Summary: Towards improved glucose control, applying sub-minute pressure at physiological levels enhances therapeutic insulin transport from macroencapsulated islets.

    View details for DOI 10.1101/2023.12.11.570688

    View details for PubMedID 38168181

  • Conductive gradient hydrogels allow spatial control of adult stem cell fate. Journal of materials chemistry. B Song, S., McConnell, K. W., Shan, D., Chen, C., Oh, B., Sun, J., Poon, A. S., George, P. M. 2024

    Abstract

    Electrical gradients are fundamental to physiological processes including cell migration, tissue formation, organ development, and response to injury and regeneration. Current electrical modulation of cells is primarily studied under a uniform electrical field. Here we demonstrate the fabrication of conductive gradient hydrogels (CGGs) that display mechanical properties and varying local electrical gradients mimicking physiological conditions. The electrically-stimulated CGGs enhanced human mesenchymal stem cell (hMSC) viability and attachment. Cells on CGGs under electrical stimulation showed a high expression of neural progenitor markers such as Nestin, GFAP, and Sox2. More importantly, CGGs showed cell differentiation toward oligodendrocyte lineage (Oligo2) in the center of the scaffold where the electric field was uniform with a greater intensity, while cells preferred neuronal lineage (NeuN) on the edge of the scaffold on a varying electric field at lower magnitude. Our data suggest that CGGs can serve as a useful platform to study the effects of electrical gradients on stem cells and potentially provide insights on developing new neural engineering applications.

    View details for DOI 10.1039/d3tb02269b

    View details for PubMedID 38291979

  • A disposable reader-sensor solution for wireless temperature logging DEVICE Kananian, S., Rho, J., Chen, C., Mirjalili, S., Daus, A., Kim, M., Niu, S., Pop, E., Wong, H., Bao, Z., Mani, A., Poon, A. Y. 2023; 1 (6)
  • A systematic review on functional electrical stimulation based rehabilitation systems for upper limb post-stroke recovery. Frontiers in neurology Khan, M. A., Fares, H., Ghayvat, H., Brunner, I. C., Puthusserypady, S., Razavi, B., Lansberg, M., Poon, A., Meador, K. J. 2023; 14: 1272992

    Abstract

    Stroke is one of the most common neurological conditions that often leads to upper limb motor impairments, significantly affecting individuals' quality of life. Rehabilitation strategies are crucial in facilitating post-stroke recovery and improving functional independence. Functional Electrical Stimulation (FES) systems have emerged as promising upper limb rehabilitation tools, offering innovative neuromuscular reeducation approaches.The main objective of this paper is to provide a comprehensive systematic review of the start-of-the-art functional electrical stimulation (FES) systems for upper limb neurorehabilitation in post-stroke therapy. More specifically, this paper aims to review different types of FES systems, their feasibility testing, or randomized control trials (RCT) studies.The FES systems classification is based on the involvement of patient feedback within the FES control, which mainly includes "Open-Loop FES Systems" (manually controlled) and "Closed-Loop FES Systems" (brain-computer interface-BCI and electromyography-EMG controlled). Thus, valuable insights are presented into the technological advantages and effectiveness of Manual FES, EEG-FES, and EMG-FES systems.The review analyzed 25 studies and found that the use of FES-based rehabilitation systems resulted in favorable outcomes for the stroke recovery of upper limb functional movements, as measured by the FMA (Fugl-Meyer Assessment) (Manually controlled FES: mean difference = 5.6, 95% CI (3.77, 7.5), P < 0.001; BCI-controlled FES: mean difference = 5.37, 95% CI (4.2, 6.6), P < 0.001; EMG-controlled FES: mean difference = 14.14, 95% CI (11.72, 16.6), P < 0.001) and ARAT (Action Research Arm Test) (EMG-controlled FES: mean difference = 11.9, 95% CI (8.8, 14.9), P < 0.001) scores. Furthermore, the shortcomings, clinical considerations, comparison to non-FES systems, design improvements, and possible future implications are also discussed for improving stroke rehabilitation systems and advancing post-stroke recovery. Thus, summarizing the existing literature, this review paper can help researchers identify areas for further investigation. This can lead to formulating research questions and developing new studies aimed at improving FES systems and their outcomes in upper limb rehabilitation.

    View details for DOI 10.3389/fneur.2023.1272992

    View details for PubMedID 38145118

    View details for PubMedCentralID PMC10739305

  • Wirelessly Powered-Electrically Conductive Polymer System for Stem Cell Enhanced Stroke Recovery. Advanced electronic materials Santhanam, S., Chen, C., Oh, B., McConnell, K. W., Azadian, M. M., Patel, J. J., Gardner, E. E., Tanabe, Y., Poon, A. S., George, P. M. 2023; 9 (10)

    Abstract

    Effective stroke recovery therapeutics remain limited. Stem cell therapies have yielded promising results, but the harsh ischemic environment of the post-stroke brain reduces their therapeutic potential. Previously, we developed a conductive polymer scaffold system that enabled stem cell delivery with simultaneous electrical modulation of the cells and surrounding neural environment. This wired polymer scaffold proved efficacious in optimizing ideal conditions for stem cell mediated motor improvements in a rodent model of stroke. To further enable preclinical studies and enhance translational potential, we identified a method to improve this system by eliminating its dependence upon a tethered power source. We have herein developed a wirelessly powered, electrically conductive polymer system that eases therapeutic application and enables full mobility. As a proof of concept, we demonstrate that the wirelessly powered scaffold is able to stimulate neural stem cells in vitro, as well as in vivo in a rodent model of stroke. This system modulates the stroke microenvironment and increases the production of endogenous stem cells. In summation, this novel, wirelessly powered conductive scaffold can serve as a mobile platform for a wide variety of therapeutics involving electrical stimulation.

    View details for DOI 10.1002/aelm.202300369

    View details for PubMedID 38045756

    View details for PubMedCentralID PMC10691593

  • Wirelessly Powered-Electrically Conductive Polymer System for Stem Cell Enhanced Stroke Recovery ADVANCED ELECTRONIC MATERIALS Santhanam, S., Chen, C., Oh, B., McConnell, K. W., Azadian, M. M., Patel, J. J., Gardner, E. E., Tanabe, Y., Poon, A. Y., George, P. M. 2023
  • Remotely controlled near-infrared-triggered photothermal treatment of brain tumours in freely behaving mice using gold nanostars. Nature nanotechnology Arami, H., Kananian, S., Khalifehzadeh, L., Patel, C. B., Chang, E., Tanabe, Y., Zeng, Y., Madsen, S. J., Mandella, M. J., Natarajan, A., Peterson, E. E., Sinclair, R., Poon, A. S., Gambhir, S. S. 2022

    Abstract

    Current clinical brain tumour therapy practices are based on tumour resection and post-operative chemotherapy or X-ray radiation. Resection requires technically challenging open-skull surgeries that can lead to major neurological deficits and, in some cases, death. Treatments with X-ray and chemotherapy, on the other hand, cause major side-effects such as damage to surrounding normal brain tissues and other organs. Here we report the development of an integrated nanomedicine-bioelectronics brain-machine interface that enables continuous and on-demand treatment of brain tumours, without open-skull surgery and toxicological side-effects on other organs. Near-infrared surface plasmon characteristics of our gold nanostars enabled the precise treatment of deep brain tumours in freely behaving mice. Moreover, the nanostars' surface coating enabled their selective diffusion in tumour tissues after intratumoral administration, leading to the exclusive heating of tumours for treatment. This versatile remotely controlled and wireless method allows the adjustment of nanoparticles' photothermal strength, as well as power and wavelength of the therapeutic light, to target tumours in different anatomical locations within the brain.

    View details for DOI 10.1038/s41565-022-01189-y

    View details for PubMedID 35995855

  • Robust Wireless Interrogation of Fully-Passive RLC Sensors IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS Kananian, S., Alexopoulos, G., Poon, A. Y. 2022
  • Activation of UCP1-Independent Ca2+ Cycling Thermogenesis by Wireless Optogenetics. Methods in molecular biology (Clifton, N.J.) Ikeda, K., Tajima, K., Tanabe, Y., Poon, A. S., Kajimura, S. 2022; 2448: 131-139

    Abstract

    The identification of non-canonical UCP1-independent thermogenic mechanisms offers new opportunities to target such pathways to improve metabolic health. Based on our recent studies on Ca2+ futile cycling thermogenesis in beige fat, we applied the newly developed implantable wireless optogenetic system to activate Ca2+ cycling in an adipocyte-specific manner without external stimuli, i.e., fat-specific cold mimetics. Here, we describe the detailed methodology and application to the prevention of obesity.

    View details for DOI 10.1007/978-1-0716-2087-8_9

    View details for PubMedID 35167095

  • High-specific-power flexible transition metal dichalcogenide solar cells. Nature communications Nassiri Nazif, K., Daus, A., Hong, J., Lee, N., Vaziri, S., Kumar, A., Nitta, F., Chen, M. E., Kananian, S., Islam, R., Kim, K., Park, J., Poon, A. S., Brongersma, M. L., Pop, E., Saraswat, K. C. 2021; 12 (1): 7034

    Abstract

    Semiconducting transition metal dichalcogenides (TMDs) are promising for flexible high-specific-power photovoltaics due to their ultrahigh optical absorption coefficients, desirable band gaps and self-passivated surfaces. However, challenges such as Fermi-level pinning at the metal contact-TMD interface and the inapplicability of traditional doping schemes have prevented most TMD solar cells from exceeding 2% power conversion efficiency (PCE). In addition, fabrication on flexible substrates tends to contaminate or damage TMD interfaces, further reducing performance. Here, we address these fundamental issues by employing: (1) transparent graphene contacts to mitigate Fermi-level pinning, (2) MoOx capping for doping, passivation and anti-reflection, and (3) a clean, non-damaging direct transfer method to realize devices on lightweight flexible polyimide substrates. These lead to record PCE of 5.1% and record specific power of 4.4Wg-1 for flexible TMD (WSe2) solar cells, the latter on par with prevailing thin-film solar technologies cadmium telluride, copper indium gallium selenide, amorphous silicon and III-Vs. We further project that TMD solar cells could achieve specific power up to 46Wg-1, creating unprecedented opportunities in a broad range of industries from aerospace to wearable and implantable electronics.

    View details for DOI 10.1038/s41467-021-27195-7

    View details for PubMedID 34887383

  • A microwave method to remotely assess the abdominal fat thickness AIP ADVANCES Lee, J., Park, A. J., Tanabe, Y., Poon, A. Y., Kim, S. 2021; 11 (3)

    View details for DOI 10.1063/5.0025865

    View details for Web of Science ID 000630480600011

  • Controlling properties of human neural progenitor cells using 2D and 3D conductive polymer scaffolds. Scientific reports Song, S., Amores, D., Chen, C., McConnell, K., Oh, B., Poon, A., George, P. M. 2019; 9 (1): 19565

    Abstract

    Human induced pluripotent stem cell-derived neural progenitor cells (hNPCs) are a promising cell source for stem cell transplantation to treat neurological diseases such as stroke and peripheral nerve injuries. However, there have been limited studies investigating how the dimensionality of the physical and electrical microenvironment affects hNPC function. In this study, we report the fabrication of two- and three-dimensional (2D and 3D respectively) constructs composed of a conductive polymer to compare the effect of electrical stimulation of hydrogel-immobilized hNPCs. The physical dimension (2D vs 3D) of stimulating platforms alone changed the hNPCs gene expression related to cell proliferation and metabolic pathways. The addition of electrical stimulation was critical in upregulating gene expression of neurotrophic factors that are important in regulating cell survival, synaptic remodeling, and nerve regeneration. This study demonstrates that the applied electrical field controls hNPC properties depending on the physical nature of stimulating platforms and cellular metabolic states. The ability to control hNPC functions can be beneficial in understanding mechanistic changes related to electrical modulation and devising novel treatment methods for neurological diseases.

    View details for DOI 10.1038/s41598-019-56021-w

    View details for PubMedID 31863072

  • A wireless body area sensor network based on stretchable passive tags NATURE ELECTRONICS Niu, S., Matsuhisa, N., Beker, L., Li, J., Wang, S., Wang, J., Jiang, Y., Yan, X., Yuri, Y., Burnetts, W., Poon, A. Y., Tok, J., Chen, X., Bao, Z. 2019; 2 (8): 361–68
  • Optimization of Sine-Wave Clocking for High-Frequency AC-DC Conversion IEEE TRANSACTIONS ON POWER ELECTRONICS Hsu, S., Poon, A. Y. 2019; 34 (1): 391–402
  • Measuring abdominal fatness using principle of Salisbury screen ELECTRONICS LETTERS Park, J., Lee, J., Lee, B., Poon, A. Y., Lee, S., Kim, S. 2017; 53 (14): 908–9
  • Non-Coil, Optimal Sources for Wireless Powering of Sub-Millimeter Implantable Devices PROGRESS IN ELECTROMAGNETICS RESEARCH-PIER Kim, S., Ho, J. S., Poon, A. Y. 2017; 158: 99–108
  • Electromagnetic Modeling of Human Body Using High Performance Computing Ng, C., Beall, M., Ge, L., Kim, S., Klaas, O., Poon, A., Parriott, C. ELSEVIER SCIENCE BV. 2017: 107-114
  • Conformal Microwave Lens for Focusing Across Inhomogenous Tissue Ho, J. S., Poon, A. Y., IEEE IEEE. 2016: 881–82
  • An Energy Harvested Ultra-Low Power Transceiver for Internet of Medical Things Rajavi, Y., Taghivand, M., Aggarwal, K., Ma, A., Poon, A. Y., IEEE IEEE. 2016: 133–36
  • INDUCTIVE POWER TRANSFER AND FAR-FIELD RADIATION WITH SMALL DUAL-BAND ANTENNAS MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Chang, T., Tanabe, Y., Tan, B., Poon, A. 2015; 57 (5)

    View details for DOI 10.1002/mop.29014

    View details for Web of Science ID 000351835800008

  • 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
  • Miniaturized Biomedical Implantable Devices IMPLANTABLE BIOELECTRONICS Poon, A. Y., Katz, E. 2014: 45–64
  • An Energy Harvesting 2x2 60GHz Transceiver with Scalable Data Rate of 38-to-2450Mb/s for Near Range Communication 36th Annual IEEE Custom Integrated Circuits Conference (CICC) - The Showcase for Integrated Circuit Design in the Heart of Silicon Valley Taghivand, M., Rajavi, Y., Aggarwal, K., Poon, A. S. IEEE. 2014
  • 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
  • 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

    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 Web of Science ID 000322308900002

    View details for PubMedID 23887586

    View details for PubMedCentralID PMC3724179

  • Midfield wireless powering of subwavelength autonomous devices. Physical review letters Kim, S., Ho, J. S., Poon, A. S. 2013; 110 (20): 203905

    Abstract

    We obtain an analytical bound on the efficiency of wireless power transfer to a weakly coupled device. The optimal source is solved for a multilayer geometry in terms of a representation based on the field equivalence principle. The theory reveals that optimal power transfer exploits the properties of the midfield to achieve efficiencies far greater than conventional coil-based designs. As a physical realization of the source, we present a slot array structure whose performance closely approaches the theoretical bound.

    View details for DOI 10.1103/PhysRevLett.110.203905

    View details for PubMedID 25167413

  • Emerging wireless applications in biomedicine 5th IEEE International Workshop on Advances in Sensors and Interfaces (IWASI) Poon, A. IEEE. 2013: 35–35
  • A 11 mu W Sub-pJ/bit Reconfigurable Transceiver for mm-Sized Wireless Implants 35th Annual IEEE Custom Integrated Circuits Conference (CICC) - The Showcase for Circuit Design in the Heart of Silicon Valley Yakovlev, A., Jang, J., Pivonka, D., Poon, A. IEEE. 2013
  • 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

    Abstract

    A wirelessly powered and controlled implantable device capable of locomotion in a fluid medium is presented. Two scalable low-power propulsion methods are described that achieve roughly an order of magnitude better performance than existing methods in terms of thrust conversion efficiency. The wireless prototype occupies 0.6 mm × 1 mm in 65 nm CMOS with an external 2 mm × 2 mm receive antenna. The IC consists of a matching network, a rectifier, a bandgap reference, a regulator, a demodulator, a digital controller, and high-current drivers that interface directly with the propulsion system. It receives 500 μW from a 2 W 1.86 GHz power signal at a distance of 5 cm. Asynchronous pulse-width modulation on the carrier allows for data rates from 2.5-25 Mbps with energy efficiency of 0.5 pJ/b at 10 Mbps. The received data configures the propulsion system drivers, which are capable of driving up to 2 mA at 0.2 V and can achieve speed of 0.53 cm/sec in a 0.06 T magnetic field.

    View details for DOI 10.1109/TBCAS.2012.2232665

    View details for Web of Science ID 000313907800002

  • 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): 523-32

    Abstract

    A wirelessly powered and controlled implantable device capable of locomotion in a fluid medium is presented. Two scalable low-power propulsion methods are described that achieve roughly an order of magnitude better performance than existing methods in terms of thrust conversion efficiency. The wireless prototype occupies 0.6 mm × 1 mm in 65 nm CMOS with an external 2 mm × 2 mm receive antenna. The IC consists of a matching network, a rectifier, a bandgap reference, a regulator, a demodulator, a digital controller, and high-current drivers that interface directly with the propulsion system. It receives 500 μW from a 2 W 1.86 GHz power signal at a distance of 5 cm. Asynchronous pulse-width modulation on the carrier allows for data rates from 2.5-25 Mbps with energy efficiency of 0.5 pJ/b at 10 Mbps. The received data configures the propulsion system drivers, which are capable of driving up to 2 mA at 0.2 V and can achieve speed of 0.53 cm/sec in a 0.06 T magnetic field.

    View details for DOI 10.1109/TBCAS.2012.2232665

    View details for PubMedID 23853253

  • 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
  • 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 IEEE International Electron Devices Meeting (IEDM) Parizi, K. B., Yeh, A. J., Poon, A. S., Wong, H. S. IEEE. 2012
  • Electromagnetic field focusing for short-range wireless power transmission IEEE Radio and Wireless Symposium (RWS) Poon, A. 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 Asia-Pacific Microwave Conference (APMC) Tanabe, Y., Ho, J. S., Wong, H., Poon, A. S. IEEE. 2012: 418–420
  • Coding the Beams: Improving Beamforming Training in mmWave Communication System 54th Annual IEEE Global Telecommunications Conference (GLOBECOM) Tsang, Y. M., Poon, A. S., Addepalli, S. IEEE. 2011
  • Wireless communication device using adaptive beamforming Poon, A., S. Y. 2011
  • Optimal Transmit Dimension for Wireless Powering of Miniature Implants IEEE International Symposium on Antennas and Propagation (APSURSI)/USNC/URSI National Radio Science Meeting Kim, S., Poon, A. S. IEEE. 2011: 408–411
  • Detecting Human Blockage and Device Movement in mmWave Communication System 54th Annual IEEE Global Telecommunications Conference (GLOBECOM) Tsang, Y. M., Poon, A. S. IEEE. 2011
  • A Four-Channel Beamforming Down-Converter in 90-nm CMOS Utilizing Phase-Oversampling IEEE Asian Solid-State Circuits Conference (A-SSCC) Tseng, R., Li, H., Kwon, D. H., Chiu, Y., Poon, A. S. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. 2010: 2262–72
  • Optimizations of Source Distribution in Wireless Power Transmission for Implantable Devices 2010 IEEE International Symposium Antennas and Propagation/CNC-USNC/URSI Radio Science Meeting Kim, S., Poon, A. S. IEEE. 2010
  • Translating Electromagnetic Torque into Controlled Motion for use in Medical Implants 32nd Annual International Conference of the IEEE Engineering-in-Medicine-and-Biology-Society (EMBC 10) Pivonka, D., Meng, T., Poon, A. IEEE. 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 International Symposium Antennas and Propagation/CNC-USNC/URSI Radio Science Meeting Poon, A. S. IEEE. 2010
  • Miniaturization of Implantable Wireless Power Receiver Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society Poon, A. S. IEEE. 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

  • An Inherently Linear Phase-Oversampling Vector Modulator in 90-nm CMOS Tseng, R., Li, H., Kwon, D., Poon, A. Y., Chiu, Y., IEEE IEEE. 2009: 257–60
  • Locomotive Micro-Implant with Active Electromagnetic Propulsion Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society Pivonka, D., Poon, A. S., Meng, T. H. IEEE. 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

  • A mixed-signal vector modulator for eigen-beamforming receivers IEEE Trans. Circuits and Systems II Tseng, R., Poon, A., Chiu, Y. 2008; 55 (5): 479–483
  • 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
  • Optimal operating frequency in wireless power transmission for implantable devices 29th Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society Poon, A. S., O'Driscoll, S., Meng, T. H. IEEE. 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

  • 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 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
  • An energy-efficient reconfigurable baseband processor for flexible radios 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., Tse, D., 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
  • Compact feedback for closed loop MIMO systems Poon, A., S. Y. 2005
  • Spatial channel models for multiple-antenna systems Poon, A., S. Y., Tse, D., N. C., Brodersen, R., W. 2004
  • 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
  • Indoor multiple-antenna channel characterization from 2 to 8 GHz Poon, A. S., Ho, M., IEEE, IEEE, IEEE IEEE. 2003: 3519–23
  • 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
  • A 60GHz digitally controlled RF beamforming array in 65nm CMOS with off-chip antennas IEEE RFIC Symposium Lin, S., Ng, K., Wong, H., Luk, L., Wong, S. S., Poon, A. 2011
  • A mm-sized implantable power receiver with adaptive link compensation IEEE International Solid-State Circuits Conference (ISSCC) O'Driscoll, S., Poon, A., Meng, T. H. 2009
  • A mm-sized implantable wireless power receiver IEEE Engineering in Medicine and Biology Society Annual International Conference (EMBC) Poon, A. 2009
  • Fast beam training for mmWave communication system: from algorithm to circuits ACM international workshop on mmWave communications: from circuits to networks Tsang, Y. M., Lin, S., Poon, A. 2010
  • Future implantable systems IEEE Technology Time Machine Symposium (TTM) Poon, A. 2011
  • A multi-agent approach to the deregulation and restructuring of power industry Hawaii International Conference on System Sciences Poon, A., Wu, F. F., Yeung, C., Yen, J. 1998
  • An inherently linear phase-oversampling vector modulator in 90-nm CMOS IEEE Asian Solid-State Circuits Conference (ASSCC) Tseng, R., Li, H., Kwon, D., Poon, A., Chun, Y. 2009
  • Beam focused slot antenna for microstrip implants International Symposium on Antennas and Propagation (ISAP) Tanabe, Y., Wong, H., Kim, S., Ho, J., Poon, A. 2012
  • Multiple-antenna channels from a combined physical and networking perspective Asilomar Conference on Signals, Systems, and Computers Poon, A., Tse, D., Brodersen, R. W. 2002
  • The signal dimensions in multiple-antenna channels IEEE Global Telecommunications Conference (GLOBECOM) Poon, A., Tse, D., Brodersen, R. W. 2002
  • Trade-offs of performance and single chip implementation of indoor wireless multi-access receivers IEEE Wireless Communications and Networking Conference Zhang, N., Poon, A., Tse, D., Brodersen, R. W., Verdu, S. 1999
  • Successive AoA estimation: revealing the second path for 60 GHz communication system 49th Annual Allerton Conference on Communication, Control, and Computing Tsang, Y. M., Poon, A. 2011