Experimental evaluation of wearable antenna efficiency for applications in body-centric wireless networks

Wearable antennas are gaining increased attention from both industrial and research communities especially with the recent surge in number of applications for both consumer and military systems. However, accurate characterization of their performance when worn by the user is still a significant challenge with regards to both numerical and experimental evaluation considering measurement traceability and repeatability. In this paper, experimental evaluation of two flexible body-worn antennas working in the UHF band is presented and analyzed. Measurements were performed in the reverberation chamber to investigate the efficiency of the antenna structures when placed on a wideband physical phantom. Results demonstrated efficiency of around 50% for fleece-based wearable antenna, while a leather substrate based structure proved lossy with significantly reduced radiation efficiency. Measurement and simulation results show good agreement and the measurement settings applied in the reverberation chamber indicated a high level of repeatability and confidence in derived results and performance measures.