A Full-Duplex Dual Wideband Horn Antenna with High Port-to-Port Isolation

A highly isolated dual-band full-duplex antenna subsystem operating at 8-18 GHz (X-/Ku-band) and 32-40 GHz (Ka-band) is presented. Each band includes two conical horn antennas which are juxtaposed side-by-side. Dual circular polarization (CP) is generated by using a 3 dB coupler in the lower band and a septum polarizer in the upper band. The two pairs of horns are embedded within and alongside a metallic cylinder with an edge-to-edge distance of 240 mm for the X-/Ku-band and 75 mm for the Ka-band. In order to increase the Tx-Rx isolation, three sets of annular corrugations are etched on the side wall of the cylindrical cavity and conformal absorbers are added around the horns in X-/Ku-band. A prototype antenna system is fabricated and measured. The measured Tx-Rx isolation is greater than 80.9 dB in the X-/Ku-band and 71.6 dB in the Ka-band. The measured gain in the two bands is higher than 14.3, and 20.1 dBiC, respectively.