Reduction of mutual coupling in a two element patch antenna array using sub-wavelength resonators

In an antenna array the mutual coupling between the array elements affects the resultant far filed radiation pattern. This paper presents an effective solution to the problem of mutual coupling in antenna arrays by placing sub wavelength resonators like complementary split ring resonator (CSRR) and open slot split ring resonator (OSSRR) in the ground plane. A two element patch antenna array operating at 2.4GHz is designed and simulated using ANSYS HFSS. The scattering parameters are observed for varying distances between the elements and the performance of the sub-wavelength resonators are compared in each case. By placing two OSSRR cells, a substantial variation is noticed in the surface currents on the ground plane along with an efficient 37dB reduction in coupling for a very small edge to edge separation of 0.048λ between the patches. The measured results are in good agreement with the simulated results.