Antenna and Radar Front-End Design for Heartbeat Detection for Triggering Purposes of Medical Devices

This paper presents a single patch antenna design operating in 868 MHz band. The antenna is integrated in a mat for the human heartbeat detection, which in turn is used for triggering purposes of medical devices. To broaden the operating bandwidth so that the variation of the electrical properties from different patients can be neglected, a U-shape is slotted on the radiation patch and moreover a thick Teflon substrate is utilized. The feeding network is designed on the opposite layer of the radiation patch to reduce the influence on the matching from the human body. Based on two different body phantom models, two antenna prototypes were manufactured. They were measured on human body with several separation distances and the resulting shortening effects are discussed. Furthermore, the circuit design for the analysis of the measurement data is presented.