Optimum High Impedance Surface Configuration for Mutual Coupling Reduction in Small Antenna Arrays

In this paper, the electromagnetic properties of two difier- ent High Impedance Surfaces (HIS) with or without Electromagnetic Band Gap (EBG) in difierent conflgurations are investigated for mutual coupling reduction in small antenna arrays. The resonant mechanisms of these structures are studied using transmission calculations in a par- allel plate waveguide. An optimum conflguration is then proposed. It is shown that a good isolation performance can be achieved without the need of metallic vias when the structure is embedded in a metal- lic cavity, which limits signiflcantly the number of HIS cells needed to perform a good isolation and the cost of manufacture.