Study on shielding effectiveness of mushroom-type electromagnetic bandgap structures in close proximity to patch antennas

In this work, a quantitative study of the shielding effectiveness of mushroom-type electromagnetic bandgap (EBG) structures placed in close proximity to patch antennas is conducted. It is shown that the E-plane coupling between two patch antennas, mainly caused by surface waves excitation on the dielectric substrate, can be reduced by 15 dB at 24 GHz in the case that the EBG is placed at a distance of only 400 ¿m (~0.03 ¿) from the radiating apertures of the patch antennas. For this purpose, the EBG cell dimensions are adapted slightly. As a result, the feasibility of placing EBG structures close to patch antennas in order to save package/board space while maintaining high coupling suppression is shown.