Design of 2 by 2 dual-polarized antenna array with high isolation, wideband and low cross polarization

A 2 ×2 dual-polarized aperture-coupled microstrip antenna array with high isolation, broadband and low cross polarization is proposed for X-band radar systems. Two orthogonal 4-way corporate (parallel) feed networks are placed on the opposite sides of ground, which not only has a multistage structure with broadband but also provides equal amplitude and reversed phase outputs. A perforated metal plate is employed to suppress the cross polarization by blocking the radiation from feed networks. The simulation results show that the dual-polarized array exhibits an impedance bandwidth of 19.8% for vertical port and 16.7% for horizontal port. The cross polarization level is better than −33dB in E plane and −32dB in H plane, and the isolation between ports is above 35dB.