Wireless powering and the study of RF propagation through ocular tissue for development of implantable sensors

Eric Y. Chow, Chin Lung Yang, Yuehui Ouyang, Arthur L. Chlebowski, Pedro P. Irazoqui, William J. Chappell

Research output: Contribution to journalArticlepeer-review


This paper evaluates RF powering techniques, and corresponding propagation through tissue, to supply wireless-energy for miniature implantable devices used to monitor physical-conditions in real-time. To improve efficiencies an impulsive powering technique is used with short duty-cycle high instantaneous-power-bursts, which biases the rectifier in its nonlinear regime while maintaining low average input-powers. The RF rectifier consists of a modified two-stage voltage multiplier which produces the necessary turn-on voltage for standard low-power CMOS systems while supplying the required current levels. The rectifier, fabricated on the TI 130 nm CMOS process, measures 215 μm × 265 μm, and is integrated with an antenna to quantify wireless performance of the power transfer. In-vivo studies performed on New Zealand white rabbits demonstrate the ability of implanted CMOS RF rectifiers to produce 1 V across a 27 kΩ load at a distance of 5 cm with a transmit-power of just over 1.5 W. Using a pulsed-powering technique, the circuit generates just under 0.9 V output with an average transmit-power of 300 mW. The effects of implantation on the propagation of RF powering waves are quantified and demonstrated to be surmountable, allowing for the ability to supply a low-power wireless sensor through a miniature rectifier IC.

Original languageEnglish (US)
Article number5752822
Pages (from-to)2379-2387
Number of pages9
JournalIEEE Transactions on Antennas and Propagation
Issue number6 PART 2
StatePublished - Jun 2011
Externally publishedYes


  • Bio-sensor
  • biomedical applications of EM radiation
  • CMOS integrated circuits
  • EM propagation
  • implantable biomedical devices
  • RF powering

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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