A wideband stacked plate antenna with a U-shaped ground plane for UHF CMMB repeater

A wideband stacked plate antenna with a U-shaped strip and a U-shaped ground plane is proposed for UHF CMMB repeater applications. By employing a U-shaped strip feed technique and the dual-layer plate configuration, the impedance bandwidth of the plate antenna for VSWR<;1.2 (or 1.5) is broadened to 13.8% (or 21.6%), when the air substrate thickness is about 0.12λ
₀
. In addition, the antenna has a back-lobe radiation level of less than -23dB across the operating bandwidth, which attributes to the use of the U-shaped ground plane. The antenna has a cross polarization level of less than -30dB and a gain of 7.3dBi. The structure of the proposed antenna is simple and low-cost.