A Wide-Bandwidth Wearable All-Textile PIFA With Dual Resonance Modes for 5 GHz WLAN Applications

A novel wide-bandwidth wearable all-textile planar inverted-F antenna (PIFA), designed for 5 GHz wireless local area network (WLAN) applications (5.15-5.825 GHz), is proposed in this communication. By using hollow copper rivets, nylon conductive fabric, and wool felt, a PIFA with a compact structure and flexible fabrication is realized. Additional wide bandwidth is achieved by adding a pair of shorting pins and etching a slot to manipulate the dual resonances of the TM0,1/2 and TM0,3/2 modes. The variation in the electric field distributions qualitatively explains the effects of the shorting pins and the slot for these two modes. As a result, the antenna has a good performance with a measured fractional bandwidth of 18.0%, a peak gain of 5.9 dBi, and an average efficiency up to 74.1%. In addition, stable performance on a human body is obtained such that the operating bandwidth on different human tissues and under different bending conditions can cover the design band. The calculated specific absorption rate (SAR) values are 0.9307 and 0.4016 W/kg under 1 g average and 10 g average, respectively. These properties make the proposed antenna suitable for wearable systems.