A Cascaded Resonator Decoupling Network for Two Filtering Antennas with Adjacent Operating Bands

In this paper, the mutual coupling problem between two adjacent-band filtering antennas is addressed. A coupled-resonator decoupling network (DN) is co-designed with the coupled filtering antennas with little effect on the original filtering responses. By connecting this network to the coupled antennas in parallel, the mutual coupling between two 2
^nd
order filtering antennas can be suppressed dramatically, even when they are operating over the closely arranged frequency bands. A step-by-step realization of the DN is provided. To verify the concept, a prototype of decoupled antennas using the DN is presented. Full-wave simulations and measurements indicate that this coupled-resonator DN can enhance the isolation between two filtering antennas up to 30 dB with little effect on the filtering performance of each antenna.