Reconfigurable beam steering antenna using U-slot fabric patch for wrist-wearable applications

A reconfigurable beam-steering patch antenna with a U-slot is presented for wrist-wearable applications. The proposed antenna was manufactured on a fabric substrate and was designed to steer the beam directions at an operation frequency of 6 GHz. In order to implement the beam-steering capability, the antenna used two PIN diodes. The maximum beam directions of three states (S ₀, S₁, and S₂) were steerable in the YZ-plane (θ=3°, 35°, and 324°, respectively). The measured peak gains were 6.1-7.7 dBi and the overall halfpower beamwidth was 108°. In addition, the simulated specific absorption rate (SAR) values of the antenna on the wrist were less than 0.992 W/kg in all states, satisfying the SAR criteria of the USA and the EU.