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Wireless powering and communication for implants, based on a Royer oscillator with radio and near-field links
Journal Contribution - Journal Article
© 2016 A compact wireless power and communication development system for implantable devices was designed and tested with two receiver circuits based on a 433 MHz separate RF link and a uni-directional near-field communication link that uses the powering field. The power transmitter was designed around a Royer oscillator with additional hardware for power and frequency control using a novel Schottky varactor method allowing 560 kHz frequency shift. The near-field link was found to be at least 10 times more efficient than the separate radio in terms of data rate vs. power consumption when used in similar circumstances with the same receiving coil, as well as requiring much less board space. Furthermore, a second system was designed to extend the study of near-field communication to include a bidirectional link as well as to correct the deficiencies of the first system that included problems with noise and parasitic oscillations. The main goal of this system was to assess the efficiency of power transfer for short range (subcutaneous) mm-size implants with flexible cuff-like transmitting coils. A 1.5 W power transfer was achieved with up to 32% efficiency, yielding downlink and uplink data rates of 20 kbps and 400 bps respectively. Finally, effects of load impedance and tissue losses on efficiency were measured and discussed.
Journal: Sensors and Actuators. A, Physical
Pages: 273 - 280
Number of pages: 8