An Implantable RFID Sensor Tag toward Continuous Glucose Monitoring

TLDR

The system has a power sensitivity of –4 dBm. The paper presents a wirelessly powered implantable electrochemical sensor tag that reliably and accurately measures changing blood glucose levels for continuous monitoring. The tag is powered by a 13.56‑MHz inductive link, communicates via ISO 15693 RFID, and incorporates a long‑term glucose sensor, ferrite antenna, RFID front‑end, potentiostat, 10‑bit sigma‑delta ADC, on‑chip temperature sensor, and digital baseband, all fabricated in SMIC 0.13‑µm CMOS on a 1.2 mm × 2 mm die with 50 µW consumption, requiring only a tuned antenna and glucose microsensor off‑chip. The tag measures glucose from 0 to 30 mM with a sensitivity of 0.75 nA/mM.

Abstract

This paper presents a wirelessly powered implantable electrochemical sensor tag for continuous blood glucose monitoring. The system is remotely powered by a 13.56-MHz inductive link and utilizes an ISO 15693 radio frequency identification (RFID) standard for communication. This paper provides reliable and accurate measurement for changing glucose level. The sensor tag employs a long-term glucose sensor, a winding ferrite antenna, an RFID front-end, a potentiostat, a 10-bit sigma-delta analog to digital converter, an on-chip temperature sensor, and a digital baseband for protocol processing and control. A high-frequency external reader is used to power, command, and configure the sensor tag. The only off-chip support circuitry required is a tuned antenna and a glucose microsensor. The integrated chip fabricated in SMIC 0.13-μm CMOS process occupies an area of 1.2 mm × 2 mm and consumes 50 μW. The power sensitivity of the whole system is -4 dBm. The sensor tag achieves a measured glucose range of 0-30 mM with a sensitivity of 0.75 nA/mM.