Mutual coupling reduction in microstrip antennas by using dual layer uniplanar compact EBG (UC-EBG) structure

Electromagnetic band-gap (EBG) structures can serve in the reduction of mutual coupling by using their capability of suppressing surface waves propagation in a given frequency range. In this paper, a dual layer uni-planar compact EBG (UC-EBG) structure is analyzed and its dispersion diagram is extracted using the commercial finite element full wave solver High Frequency Structure Simulation (HFSS). This UC-EBG structure can be built using planar fabrication technique without any modification. The dual layer UC-EBG structure, having a lower resonant frequency than the single layer one, is inserted between E-plane coupled microstrip antenna arrays to reduce the mutual coupling. This method has been verified by the HFSS simulations and as a result, a significant 17 dB mutual coupling reduction is noticed from the simulations.