Radiation Efficiency-Improvement Using a Via-Less, Planar ZOR Antenna for Wireless ECG Sensors on a Lossy Medium

Abstract

The critical issues involving severe radiation efficiency degradations during wireless electrocardiogram (ECG) health monitoring sessions are addressed by devising a monolithic zeroth-order resonance (ZOR) antenna. The presented antenna consists of a composite right/left-handed (CRLH) structure that is realized on a single, planar surface of the flexible printed circuit board (PCB) without the use of any via-holes. This significantly alleviates the complexity and fabrication cost involved with vertically polarized antennas with monopole-like radiation patterns, which are important factors in consumer electronics. Moreover, this letter investigates the practical issues associated with effects of the in-house designed ECG device circuit board, feeding mechanism with the RFIC, as well as the polycarbonate chassis. The finalized antenna is less than in total horizontal dimension with zero height profile. Measurement confirms the presented antenna features more than 30% radiation efficiency across 80 MHz bandwidth when completely integrated within the ECG sensor device and placed on the human body phantom.