An Electronically Reconfigurable Dual-Mode Dual-Band Ring Antenna Based on CMA

In this work, an electronically reconfigurable dual-band dual-mode microstrip ring antenna is proposed. By performing a characteristic mode analysis (CMA) on the ring antenna, two modes are identified that can be used together to cover with their radiation the entire half space. Notably, to excite these modes, an electronically reconfigurable matching network is developed. Due to the inherent orthogonality of characteristic modes, isolation greater than 60 dB is achieved between the antenna's ports for our two selected modes of operation.