AMC-Backed Flexible Near-Endfire Wearable Antennas for On-Body Communications

This chapter presents a multi-layered artificial magnetic conductor (AMC)-backed endfire planar Yagi antenna on a flexible latex substrate, such that the bidirectional-endfire radiation is altered to an off-axis beam tilt in the near-endfire direction. It discusses a novel technique of combining endfire radiation wearable planar antennas with AMCs for improving the antenna tolerance when positioned on the human body. A conventional planar Yagi antenna was combined with single- and double-layered AMC surfaces to change the direction of radiation from bidirectional-endfire to near-endfire off-axis beam-tilt radiation. The free-space and on-body analyses were performed using the CST MWS voxel model for common antenna properties, such as return loss, gain, frequency shifting, radiation efficiency, and peak specific absorption rate (SAR) level considering body-worn applications. The fabricated double-layered AMC-backed Yagi antenna prototype on latex substrate demonstrates acceptable return loss bandwidth and endfire gain to be used for wireless body area network (WBAN) applications in 2.4 GHz ISM band. © 2016 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved.