A fast and accurate automatic matching network designed for ultra low power medical applications

Abstract

We present a method to automatically match a system to the load variation accurately with a very short matching time for Ultra Low Power medical applications. A demonstrator was fabricated and an experimental set-up in the Medical Implant Communication System (MICS) frequency band of 402–405MHz was realized including a pacemaker antenna prototype immersed on a homogeneous lossy liquid. The matching network consists of a low pass π structure with tunable components made of varactors. Methodologies for simplifying the matching network design are introduced. The measurements show that a S11 up to −30dB is obtained with a matching time of 900µs.