Cavity-backed folded-slot antenna

CPW-fed CBFSAs designed at 4.5 GHz is proposed in this paper. From simulation and fabrication results, it was found that the CBFSA which used a shallow cavity (λ
_o
/40≈λ
_d
/22) is able to focus the radiation pattern on one side of the substrate and gain of 4.28 dB is obtained. This CBFSA with a shallow cavity may find applications where uni-directionality and limited size in designs are required.