Orientation Mug Shot
  • Assistant Professor, Elect & Computer Engineering

Publications

  • A.T. Gardner, H.J. Strathman, D.J. Warren & R.M. Walker (2018). Impedance and noise characterizations of Utah and microwire electrode arrays. IEEE Journal of Electromagnetics, RF, and Microwaves in Medicine and Biology. Vol. 2, 1-8. Published, 12/01/2018.
    http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arn...
  • A.T. Gardner, R.M. Walker, H.J. Strathman & D.J. Warren (2018). Signal and noise sources from microwire arrays implanted in rodent cortex. IEEE Life Sciences Conference. 97-100. Published, 10/30/2018.
    http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arn...
  • J. Liu & R.M. Walker (2018). A compact, low-noise, chopped front-end for peripheral nerve recording in 180 nm CMOS. IEEE Biomedical Circuits and Systems Conference (BioCAS). 1-4. Published, 10/19/2018.
    http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arn...
  • T. Ahmed, N. Tasneem & R.M. Walker (2018). High-speed communication up to 600 Mbps over FDA-cleared implantable wirelines. IEEE Biomedical Circuits and Systems Conference (BioCAS). 1-4. Published, 10/19/2018.
    http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arn...
  • A. Nag, A. Shafiee, R. Balasubramonian, V. Srikumar, R. Walker, J.P. Strachan & N. Muralimanohar (2018). Newton: Gravitating towards the physical limits of crossbar acceleration. IEEE Micro. Vol. 38, 41-49. Published, 09/27/2018.
    http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arn...
  • M. Sharma, A.T. Gardner, H.J. Strathman, D.J. Warren, J. Silver & R.M. Walker (2018). Acquisition of neural action potentials using rapid multiplexing directly at the electrodes. Micromachines. Vol. 9. Published, 09/20/2018.
    https://www.mdpi.com/2072-666X/9/10/477
  • A. T. Gardner, J. Mize, D. Warren & R. M. Walker (2017). Comparative characterization of in vivo and in vitro noise of the SIROF Utah Electrode Array. 2017 IEEE SENSORS. 1-3. Published, 12/2017.
    https://doi.org/10.1109/ICSENS.2017.8233915
  • R. M. Walker, I. S. Subramanian, A. A. Bajwa, L. Rieth, J. Silver, T. Ahmed, N. Tasneem, M. Sharma & A. T. Gardner (2017). Integrated neural interfaces. IEEE Midwest Symposium on Circuits and Systems (MWSCAS). 1045-1048. Published, 10/2017.
    https://doi.org/10.1109/MWSCAS.2017.8053106
  • T. Ahmed, N. Tasneem & R. M. Walker (2017). Feedforward-equalized communication link for implantable systems achieving 400 Mbps. Biomedical Engineering Society Annual Meeting (BMES). Published, 10/2017.
    http://submissions.mirasmart.com/BMESArchive/Brows...
  • C. Gupta, R. M. Walker, S. Chang, S. R. Fischer, M. Seal, B. Murmann & R. T. Howe (2017). Quantum tunneling currents in a nanoengineered electrochemical system. The Journal of Physical Chemistry C. Vol. C, 15085-15105. Published, 07/2017.
    https://pubs.acs.org/doi/10.1021/acs.jpcc.7b04350
  • N. Tasneem, T. Ahmed and R. M. Walker, "Wireline communication over an implantable lead," IEEE EMBS Conference on Biomedical Engineering and Sciences (IECBES), 2016, pp. 321-325, 2016. Published, 12/2016.
    https://doi.org/10.1109/IECBES.2016.7843466
  • M. Sharma, A. T. Gardner, J. Silver and R. M. Walker, “Noise and impedance of the SIROF Utah Electrode Array,” IEEE SENSORS, pp. 1-3, 2016. Published, 11/2016.
    https://doi.org/10.1109/ICSENS.2016.7808826
  • P.E. Gaillardon, M. Hasan, A. Saha, L. Amarú, R. Walker and B.S. Rodriguez, "Digital, analog and RF design opportunities of three-independent-gate transistors," IEEE International Symposium on Circuits and Systems (ISCAS), pp. 405-408, 2016. Published, 05/2016.
    https://doi.org/10.1109/ISCAS.2016.7527256
  • P.E. Gaillardon, R. Magni, L. Amaru, M. Hasan, R. Walker, B.S. Rodriguez, J.F. Christmann, E. Beigne, "Three-Independent-Gate Transistors: Opportunities in digital, analog and RF applications," Latin-American Test Symposium (LATS), pp. 195-200, 2016. Published, 04/2016.
    https://doi.org/10.1109/LATW.2016.7483368
  • J.D. Foster, P. Nuyujukian, O. Freifeld, H. Gao, R. Walker, S.I. Ryu, T.H. Meng, B. Murmann, M.J. Black, K.V. Shenoy, "A freely-moving monkey treadmill model," Journal of Neural Engineering, vol. 11, no. 4, 046020 (14pp.). Published, 07/2014.
    http://dx.doi.org/10.1088/1741-2560/11/4/046020
  • C. Gupta, R.M. Walker, R. Gharpuray, M. Shulaker, Z. Zhang, M. Javanmard, R.W. Davis, B. Murmann, R.T. Howe, “Electrochemical quantum tunneling for electronic detection and characterization of biological toxins,” Proc. of SPIE: Micro- and Nanotechnology Sensors, Systems, and Applications, vol. 8373, no. 4, pp. 837303-1-837303-14. Published, 05/2012.
    http://dx.doi.org/10.1117/12.920692
  • H. Gao, R.M. Walker, P. Nuyujukian, K.A.A. Makinwa, K.V. Shenoy, B. Murmann, T.H. Meng, “HermesE: A 96-channel full data rate direct neural interface in 0.13μm CMOS,” IEEE Journal of Solid-State Circuits, vol. 47, no. 4, pp. 1043-1055. Published, 04/2012.
    http://dx.doi.org/10.1109/JSSC.2012.2185338
  • R.M. Walker, H. Gao, P. Nuyujukian, K.A.A. Makinwa, K.V. Shenoy, T.H. Meng, B. Murmann, "A 96-channel full data rate direct neural interface in 0.13μm CMOS," 2011 Symposium on VLSI Circuits, pp.144-145. Published, 06/2011.
    http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arn...
  • E.M. Kanter, R.M. Walker, S.L. Marion, M. Brewer, P.B. Hoyer, J.K. Barton, “Dual modality imaging of a novel rat model of ovarian carcinogenesis,” Journal of Biomedical Optics, vol. 11, no. 4, pp. 41123-1-10. Published, 07/2006.
    http://dx.doi.org/10.1117/1.2236298
  • E. Kanter, R. Walker, S. Marion, P. Hoyer, and J.K. Barton, “Use of multiple imaging modalities to detect ovarian cancer,” Proc. of SPIE: Photonic Therapeutics and Diagnostics, vol. 5686, pp. 596-605. Published, 05/2005.
    http://dx.doi.org/10.1117/12.585560

Research Statement

My research revolves around sensing systems, with a particular focus on implantable devices and biomedical applications. My group is working to advance knowledge in the areas of electronic circuit and system design, data readout and processing, integrated device design, and in vivo device characterization. Our extensive work on neural interface technology is relevant to experimental neuroscience, brain machine interfacing, neuromodulation, neural prosthetics, medical diagnostics, and disease state monitoring. A core theme of our approach is holistic, system-aware design drawing from subjects such as mixed signal integrated circuits, instrumentation and measurement methodology, embedded systems, sensor and device physics, and signal processing.

Research Keywords

  • Sensor Systems
  • Neural Interfaces
  • Brain Machine Interfaces
  • Mixed Signal Electronics
  • Integrated Circuits
  • Signal Conditioning
  • Analog Design
  • Neural Engineering
  • Embedded Systems
  • Signal Processing
  • Biomedical Engineering
  • Biosensors

Presentations

  • Strategies for Scaling Neural Interface Recording and Stimulation Systems, Panel Session at the 2018 Neural Interfaces Conference. Invited Talk/Keynote, Presented, 06/25/2018.
  • Direct Neural Interfaces for Medical and Non-Medical Applications, 2018 Emerging Technologies Conference (ET CMOS), Whistler, BC, CA. Invited Talk/Keynote, Presented, 05/10/2018.
  • R. M. Walker, I. S. Subramanian, A. A. Bajwa, L. Rieth, J. Silver, T. Ahmed, N. Tasneem, M. Sharma, and A. T. Gardner, “Integrated neural interfaces,” IEEE Midwest Symposium on Circuits and Systems (MWSCAS), 2017, pp. 1045-1048. Conference Paper, Refereed, Presented, 08/06/2017.
    http://ieeexplore.ieee.org/document/8053106/
  • Neural Interface Circuits and Systems Half Day Tutorial, 2017 IEEE International Symposium on Circuits and Systems (ISCAS), Baltimore, Maryland. Invited Talk/Keynote, Other, 05/28/2017.
  • Design of Reliable Neural Interfaces 2016 Annual BRAIN Initiative Principal Investigators Meeting, Bethesda, Maryland. Invited Talk/Keynote, Presented, 12/14/2016.
  • Rapid Electrode Multiplexing for Scalable Neural Recording 2016 Annual BRAIN Initiative Principal Investigators NIH pre-meeting, Bethesda, Maryland. Invited Talk/Keynote, Presented, 12/11/2016.
  • Physiological Sensor Systems Physiologically Aware Virtual Agents Workshop, 2016 Intelligent Virtual Agents Conference (IVA), Los Angeles, CA. Invited Talk/Keynote, Presented, 09/20/2016.
    http://iva2016.ict.usc.edu/can-you-feel-me-now-cre...
  • Integrated Neural Interfaces Army Research Laboratories, Adelphi, Maryland. Invited Talk/Keynote, Presented, 06/30/2016.
  • Integrated Neural Interfaces Stanford System-X Seminar Series, Stanford University, Stanford, CA . Invited Talk/Keynote, Presented, 05/19/2016.
    https://systemx.stanford.edu/events/seminar/201605...
  • Breakthroughs in Analog and RF Circuit Performance through Steep-Slope FinFETs 2016 GOMACTech Conference, Orlando, FL. Conference Paper, Refereed, Presented, 03/17/2016.
  • Front-End ASIC Design for the HermesE/F Wireless Neural Interface Systems 1st Bernstein Sparks Workshop Towards Long-Term Cortical Neuro-Interfaces . Invited Talk/Keynote, Presented, 03/06/2013.
    http://portal.uni-freiburg.de/nncn/termine-en/cort...