Microstrip antenna arrays on thin substrates with electromagnetic band-gap structures

In this paper, the isolation properties of four different electromagnetic band-gap (EBG) structures are compared on a thin and low dielectric constant substrate. The isolation effect is studied with EBG structures applied between two microstrip patch antennas at 2.4 GHz. One of the EBGs is a novel two-dimensional (2-D) fork-like structure, which is found to be the most isolative structure of the compared with 6 dB minimum and 21 dB maximum attenuation in simulations. The mutual coupling results are verified by measurements and also radiation patterns are measured. The fork-like EBG is also applied to a planar four antenna array. Then, the proposed EBG is applied to a linear four antenna array. The effect on return loss is studied by simulations as the array is beam scanned by adding phase shift between antenna elements. More stable results are found when using EBG structures with the antenna array.