A Dual-Polarized Microstrip Patch Antenna with High Port Isolation Based on AMC Surface

A high port isolation dual-polarized microstrip patch antenna based on artificial magnetic conductor (AMC) surface is proposed in this paper. The antenna is composed of two stacked patches and H-shaped coupled slots with improved impedance matching bandwidth. The feed network is composed of two orthogonal microstrip feed lines for dual polarizations, and metallic vias are arranged around them to improve the port isolation. The AMC surface is designed and loaded below the feed lines. The electric field coupling between the feeding slots on the ground are reduced, and the port isolation is greatly improved. The simulated results show that the proposed antenna has a port isolation better than 48 dB and a cross-polarization level of -26 dB over the frequency of 9.3-9.5 GHz. Moreover, based on zero-reflection phase characteristic of the AMC, the profile of the antenna is reduced to 7.3 mm (0.23 lambda 0, lambda 0 is the wavelength at 9.4 GHz). A prototype is fabricated to verify the analysis of proposed antenna. The measured results indicate that a high port isolation better than 44 dB and a cross-polarization level lower than -22 dB are achieved. The maximum gain is higher than 6.98 dBi and 6.5 dBi for the vertical and horizontal polarizations, respectively. With the advantages of high port isolation and low profile, this antenna offers a good candidate for weather radar applications.