Mutual Coupling Reduction using Octagon Frequency Selective Surface Structure for Full Duplex Applications

This paper presents a novel Frequency Selective Surface (FSS) structure to effectively decrease the mutual coupling between two antennas. A novel Octagon Star Shaped Slot Frequency Selective Surface (OSSS-FSS) structure is designed and analyzed to operate at a center frequency of 3.5 GHz. The OSSS-FSS structure is able to confine the surface current resulting in overcoming the mutual coupling when placed between two mutually coupled antennas. The structure improves the coupling isolation up to 14.8 dB against using air or substrate between two antennas and can suppress the surface current across wide frequencies bandwidth of 1.1 GHz. The proposed OSSS-FSS structure is a great candidate to use for full-duplex 5G applications or stealth technology.