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International Journal of Antennas and Propagation
Volume 2015, Article ID 539843, 7 pages
http://dx.doi.org/10.1155/2015/539843
Research Article

Wearable Fabric Reconfigurable Beam-Steering Antenna for On/Off-Body Communication System

Graduate School of NID Fusion Technology, Seoul National University of Technology, 172 Gongneung 2-dong, Nowon-gu, Seoul 139-743, Republic of Korea

Received 20 October 2014; Revised 12 December 2014; Accepted 29 December 2014

Academic Editor: N. Nasimuddin

Copyright © 2015 Seonghun Kang and Chang Won Jung. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper presents a comparison of on-body performances between omnidirectional (loop antenna) and reconfigurable beam-steering antennas. Both omnidirectional and reconfigurable antennas were manufactured on the same fabric substrate and operated at the frequency band of the WLAN 802.11a (5.725–5.85 GHz). The reconfigurable antenna was designed to steer the beam directions. In order to implement the beam-steering capability, the antenna used two PIN diodes. The maximum beam directions of three states (states 0, 1, and 2) were steerable in the -plane (°, 28°, and 326°, resp.). The measured peak gains were 5.9–6.6 dBi and the overall half power beam width (HPBW) was 102°. The measured results of total radiated power (TRP) and total isotropic sensitivity (TIS) indicated that the communication efficiency of the reconfigurable beam steering antenna was better than that of the loop antenna. When the input power was 0.04 W (16 dBm), the simulated specific absorption rate (SAR) values of the reconfigurable beam steering antenna on the body were less than 0.979 W/kg (1 g tissue) in all states, satisfying the SAR criteria of the US.