High port isolation of a dual polarized microstrip antenna array using DGS

In this paper, high port isolation in dual feed orthogonally polarized square patch antenna array is achieved by the use of Defected Ground Structure (DGS). A simple rectangular-headed cross DGS is implanted in the ground plane underneath the square patch in order to achieve high port isolation between two orthogonal ports at 2.95 GHz. The proposed design offers 58.55 dB port isolation between ports of single element patch and 45 dB that for two-element arrays. The port isolation of microstrip antenna with and without DGS has been studied and the result indicates better port isolation of the array with high cross polarization for two orthogonal polarizations owing to the effect of DGS. Finally, the two-element array is considered for MIMO application and mutual coupling between them is investigated. The simulated results of the proposed antennas are found to be in close agreement with the experimentally measured ones.