A Wideband Metasurface Antenna With Dual-Band Dual-Mode for Body-Centric Communications

A wideband wearable metasurface antenna with dual-mode (on-body and off-body mode), dual-band, designed for the 2.45 and 5 GHz wireless body area network (WBAN), is proposed in this communication. The TM
₁₁
mode of the circular patch is used for the off-body mode in the 2.45 GHz WBAN band because of its broadside radiation pattern, meanwhile, the TM
₀₂
of the circular patch and metasurface mode are chosen for on-body mode due to their omnidirectional radiation pattern in the second band. A shorting pin is used to tune these modes to the desired operating frequencies and using polydimethylsiloxane (PDMS) makes the antenna easier to be integrated into wearable devices. The prototype is fabricated, and a good performance is realized with a measured
S
₁₁
< −10 dB functional bandwidth of 4.9% and 15.7% which can cover the 2.45 and 5 GHz WBAN band, respectively. Moreover, the measured peak gain achieves 5.5 dBi for off-body mode and 5.3 dBi for on-body mode, as well as the specific absorption rate values are lower than the limitation standards of U.S. and Europe throughout the operating band. The acquired performance demonstrates that the proposed antenna has a great potential in the wearable applications.