A 6.78 MHz wirelessly powered sensing system for the long-term monitoring of the GI tract

Abstract

This article presents a battery-free system with a 6.78 MHz wireless power transfer (WPT) link for the long-term monitoring of the gastrointestinal tract. For this purpose, a 2.7x2.7mm2 Application Specific Integrated Circuit (ASIC) is developed and validated. It enables efficient power reception at microwatt power levels deep in the human body. The ASIC is interfaced to ultra-low power electronics that measure and wirelessly transmit data from ten sensor readouts suitable for use in ingestible sensing capsules. The system’s ability to operate at a depth of 8 cm within human tissue while adhering to Specific Absorption Rate limits is demonstrated in an experimental setup.