Bio

Vaishnavi Ranganathan is a Ph.D. student in the Sensor Systems laboratory at the University of Washington (UW), Seattle, WA. Her main research interests are wireless power transfer and brain-computer interface applications, including low-power computation and communication solutions for implantable devices. She is a member of the Center for Sensorimotor Neural Engineering which is an NSF funded research center at the UW.

She received the B.Tech degree in Electronics and Instrumentation Engineering from Amrita Vishwavidyapeetham University, TN, India, in 2011, and a M.S degree in Electrical Engineering, specializing in NEMS, from Case Western Reserve University, Cleveland, OH, in 2013. As an undergraduate she gained experience in robotics and sensor design. She has also worked as a research intern in the Nanobios lab at Indian Institute of Technology, Mumbai, India, where her focus was MEMS for biomedical sensors.

Limb reanimation with fully wireless brain computer interface

Limb reanimation with fully wireless brain computer interface

The primary aim of my research is to develop a completely wireless and implantable brain-computer-spinal interface (BCSI) to reanimate patients with paralysis caused by injury in the spinal cord. Advancement in technology has led to state-of-the-art solutions for neural signal acquisition and stimulation for limb reanimation. The major challenge lies in combining them for autonomous stimulation. Another concern associated with long term implantation of these devices is the power and communication cables that exit the skin surface and pose a risk of infection.

To address these two issues, my contributions are to implement an algorithm to enable stimulation based on recorded signal and designing the analog circuits for simultaneous wireless communication and power transfer to increase the implanted operational lifetime.

I have implemented a fully wireless printed circuit design of the BCSI system as a part of a NSF funded program. Using low-power wireless communication protocols, like radio frequency (RF) backscatter at 915MHz, high data-rate communication can be established between the implant and external devices. I have also designed and implemented a digital controller for this protocol using 65nm CMOS technology.

With respect to wireless power transfer, we have successfully demonstrated inductive power delivery across tissue using optimally designed coupled resonators operating at 13.56MHz. This system is capable of achieving efficiencies greater than 70% with low temperature rise (less than 2oC).

The current focus is to utilize inherently low power on-chip digital computation to minimize dependence on external control, thereby closing the loop in the BCSI system. My goal is to contribute with my experience to the advancement of engineering in medicine by developing affordable miniaturized biomedical implants that can facilitate diagnosis for treatment and improve the quality of life for individuals with disabilities.