A Wideband Cavity-Backed Dual-Polarized Antenna for X-Band Applications

In this letter, a cavity-backed dual-polarized antenna operating in X-Band (8-12 GHz) is presented. The antenna is composed of a metal cavity with a circular slot, a dual-polarized feeding balun structure printed on a single-layer substrate, and a loaded dielectric block. The units of the antenna are fixed by screws, and no additional welding assembly is required. By setting notches structure on the dual-polarized planar feeding probes, the port isolation and polarization purity of the proposed antenna have been significantly improved. A prototype with the compact size of 0.44 x 0.44 x 0.39 ?(0) (?(0) is the wavelength at 10 GHz) is fabricated and measured. Measured results demonstrate the return losses are lower than 10 dB and the isolations are greater than 23 dB from 8 to 12 GHz, the measured bore-sight gains vary from 4.5 to 5.8 dBi, and the cross-polarization levels less than -20 dB are obtained within the operational band.