Compact All-Textile Dual-Band Antenna Loaded With Metamaterial-Inspired Structure

A dual-band, wearable metamaterial-loaded antenna is proposed for 2.4/5.2-GHz WLAN applications. The loading is with a composite right/left-handed transmission line (CRLH-TL) metamaterial, resulting in a significant miniaturization down to λ0/6 ×λ0/6 ×λ0/20. Similar radiation patterns are obtained by simultaneously exciting the first-order positive ( n=+1) and negative ( n=-1) modes. The antenna features a low backward radiation in both bands, which is highly desirable in minimizing electromagnetic coupling to the body. The antenna is fabricated fully using textiles except for the connector and is evaluated in free space and on body, under both planar and bent conditions. Besides a good agreement between simulations and measurements, results indicate that the proposed topology is reasonably immune to body coupling and robust with respect to mechanical changes. The specific absorption rate (SAR) level is numerically investigated to determine the on-body safety level.