A Wideband, Dual-Polarized, Substrate-Integrated Cavity-Backed Slot Antenna

A new technique for designing wideband dual-polarized slot antennas is presented. The proposed structure is in the form of a differentially fed cross-slot antenna backed by a shallow substrate-integrated cavity with a depth of approximately λ₀/10 . This technique takes advantage of a double-resonance observed in off-center microstrip-fed slot antennas to enhance its bandwidth to double that of typical cavity-backed cross-slot antennas of the same size. Experimental results demonstrate a bandwidth of 19%, average gain of 5.3 dBi, isolation better than 28 dB, and wideband polarization purity.