A Rubber-Based Dual-Mode Button Antenna

Natural rubber is a material of interest in the scope of antenna design because of its multiple qualities in mechanical properties, electromagnetic characteristics and economic values. To demonstrate these advantages, here we prepose a wearable button antenna based on rubber for Wireless Body Area Networks (WBAN) applications. Given the distinct demands of directional properties for on-body and off-body channels, the proposed button antenna is equipped with two operation modes at two neighbouring frequencies in the 5 GHz Wireless Local Area Network (WLAN) band. Specifically, through radiation superposition of magnetic currents, the proposed antenna is capable of simultaneously providing an end-fire pattern at 5.2 GHz and a broadside pattern at 5.6 GHz. A rubber-based prototype is fabricated and experimentally validated on a phantom, demonstrating the expected operation modes in the corresponding bandwidths for relevant body-centric communications.