Antenna design for heartbeat detection for triggering purposes of medical devices

A single patch antenna design operating in 868 MHz band is presented in this paper which is integrated in the mat for the human heartbeat detection for triggering pruposes of medical devices. To broaden the operating bandwidth so that the inadaptability from different patients can be declined, a U shape is slotted on the radiation patch and moreover a thick substrate is utilized. Feeding network is designed on the opposite layer of the radiation patch to reduce the influence on the matching from the human body. Besides, a favorable thin copper cladding prototype is also manufactured since thick metal influences significantly the results of several medical imaging techniques, e.g. angiography or computed tomography (CT). Antenna prototypes are measured on human body with different separation distance and the resulting shortening effects are discussed.