Wireless Power and Data Link for Ensembles of Sub-mm scale Implantable Sensors near 1GHz

Abstract

We describe a custom wireless power and data transmission (WPDT) link and analyze its performance in a prototype implantable sensor system of ensembles of CMOS sensor ASICs (“Neurograins”) embedding 0.5 mm × 0.5 mm planar microcoil antennas. We use near-field RF at ~1 GHz for wireless powering in a resonant 3-coil architecture including an implanted relay coil in a quadrant layout architecture to maximize coverage area and RF transfer efficiency. We demonstrate successful WPDT across antenna cross-section in benchtop proxy physiological tests. Demodulation and analysis of backscattered signals validate the data link fidelity. Our results suggest that this electromagnetic coupling scheme can robustly support a chip density of 250/ cm2(up to 1024 individual Neurograins in a 2 cm × 2 cm area) and parallel transmitters can be combined to multiply the channel capacity without destructive interference.