A Watch Strap Antenna for the Applications of Wearable Systems

A wearable antenna based on the metal watch strap is proposed. A prototype of a TISSOT classic watch is used for the demonstration. The width of the strap has only a little impact on the radiation patterns. However, the variations of the feeding location would dramatically influence the resonance frequency and the matching performance. The shapes and the graphic patterns of the wristband have contributions on the reflection coefficients as well as the radiation patterns. A fractional bandwidth of 77.8% could be obtained when feeding to the right of the dial at 2.46 GHz, which falls into the ISM (industrial, scientific, and medical) band. The main lobe is fairly wide in both E- and H-planes, which would enable the strap antenna to have a good adaptation for the various postures of the arm. The measurement results show good agreement with that of the simulations, which indicates it a potential option for the applications of wearable systems.