A Compact Absorbing FSS Structure for Antenna Decoupling in the 5G 3.5GHz Band

Antenna decoupling has gained a large interest in the last years, especially for MIMO 5G communications. In this frame, a high isolation is required between the multiple antennas of a transmitting array of a base station while preserving the specified radiation pattern and the compactness of the antenna array. Different solutions were proposed in the literature to provide decoupling performance. Among these, the absorbing frequency selective surface (FSS) structures have shown interesting properties. In this paper, a new type of compact FSS is introduced, using composite material technology and screen-printing. It takes advantage of a specific geometrical pattern that lowers its operation frequency with a similar spatial periodicity. We provide simulations of its absorbing properties together with an experimental validation of its performance. The proposed absorbing structure will be further adapted to decouple patch antennas in composite material technology.