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 journalArticle

40 Citations (Scopus)

Abstract

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
Article number5752822
Pages (from-to)2379-2387
Number of pages9
JournalIEEE Transactions on Antennas and Propagation
Volume59
Issue number6 PART 2
DOIs
Publication statusPublished - 2011 Jun 1

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering

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