A Novel Broadband and High-Isolation Dual-Polarized Microstrip Antenna Array Based on Quasi-Substrate Integrated Waveguide Technology

A
$2 \times 2$
dual-polarized (DP) aperture-coupled microstrip antenna array with high isolation, broadband, and low cross polarization for Ku-band is proposed based on the quasi-substrate integrated waveguide (Q-SIW) technology. The proposed microstrip antenna array is excited by two orthogonal four-way corporate (parallel) feed networks, which not only has a multistage structure with broadband but also provides pairs of differential outputs. The Q-SIW structure, composed of several reflectors and substrate integrated metal pillars, is used to increase the bandwidth, improve the isolation, and reduce the influence of feed network. The measured and simulated results show that the DP array exhibits an impedance bandwidth of 26.37% for vertical port and 27.77% for horizontal port. The cross polarization level is better than −34 dB and −40 dB for two ports, and the isolation between the two ports is above 32 dB.