X-band Dual-Polarized Waveguide Filtering Antenna

This paper investigates an X-band dual-polarized waveguide filtering antenna. The filtering antenna is formed by the cascade of a TE101/TE011 mode cavity, two interlaced TE031 mode cavities and four TE111 mode cavities. The TE101/TE011 mode cavity has two orthogonal electric fields and is suitable for dual-polarized application with high isolation. The TE031 mode cavity resonator, which is excited on the center and has symmetrical electric field distribution, is acting as a resonating power divider with equal amplitude and phase output. By 90 degrees rotating and duplicating the TE031 mode cavity, a cross-shaped cavity is formed. Dual-polarized radiation can be obtained by etching rectangular radiating slot on the top of each TE111 mode cavity. The measured results show that the dual-polarized antenna has a bandwidth of 4% (9.78-10.18 GHz), a peak gain of 8.5 dBi and a high isolation of 32 dB.