Mutual Coupling Reduction in Patch Antenna Arrays by Using EBG Structures

Reducing the mutual coupling between elements of an antenna array has become a hot topic in antenna arrays design. To mitigate the mutual coupling problem, it is necessary to use the electromagnetic band-gap (EBG) structures because they have an inherent bandgap feature at predefined frequency so they can reduce the surface waves excitations in printed antenna geometries. In this article, the proposed antenna array operating at 2.4 GHz is consisted of two rectangular patches and separated with various EBG structures. To eliminate surface waves and overcome the coupling between patch antenna we propose three types of EBG structures (mushroom like EBG, UC-PBG and circle EBG). These structures are printed on a high- permittivity substrate (h=3.125mm, εr = 10). The simulation results using Ansoft HFSS™ based on the finite element method (FEM) show that the size of proposed electromagnetic band gap structures (UCPBG and circle EBG) have been reduced by 49.7% and 75% compared with the conventional one and they reduced the mutual coupling by 8 dB and 13 dB respectively in H plane configuration.