An asymmetric RF tagging IC for ingestible medication compliance capsules

This paper presents a feasibility study of a low power electronic RF tagging device and a printed capsule antenna for medication compliance monitoring. RF transponders attached directly to the outer surface of a standard sized capsule can potentially serve as a cost-effective method of validating medication compliance via electronic detection of an ingested pill inside the digestive tract. The electrical radiation characteristics of a small biocompatible antenna are analyzed inside a human body model for various FCC telemetry bands using the finite difference time domain (FDTD) method. Based on this study, a novel asymmetric RF tagging IC is reported. The device is powered by low frequency AC signals to create externally detectable RF bursts in the 915MHz ISM band. A test chip was fabricated in 130nm CMOS technology and experimentally validated inside a phantom solution that mimics the human torso.