Design Considerations of Feeding Dual-Port Microstrip Square-Ring Antenna

In this paper, the design considerations for feeding dual-port microstrip square-ring antenna are discussed. In particular, the antenna is evenly divided into eight sectors for analysis with the aid of characteristic modes and electric nearfields. The results can be used to guide the design of the excitation configuration for two ports with low mutual coupling for the square-ring antenna. The rotational and mirror symmetry of eight sectors helps simplify the investigation. The results from characteristic mode analysis (CMA) have also been validated in full-wave simulation with different two-port combinations.