A Multi-Functional Compact Button Antenna for Wearable Applications

A multi-functional button antenna is designed, with dual-band and dual-polarization characteristics. This antenna is a dedicated design for wearable applications. A compact size button is achieved with a diameter of only 19.5 mm (0.29 $\lambda$), which optimizes the users’ comfort. The proposed antenna works in the 4.5-4.6 unlicensed future 5G communication band, and the 5.1-5.5 GHz WLAN band. Two radiation patterns with orthogonal linear polarizations are obtained in each band. The mutual coupling between the two patterns is below −20 dB. The antenna is prototyped. Simulations and experiments confirm the validity of this novel concept.