A Dual-band Reconfigurable Frequency Selective Surface Design Using Characteristic Mode Analysis

A dual-band reconfigurable frequency selective surface (RFSS) is designed using characteristic mode (CM) analysis. By observing the modal behaviors of the two basic structures (microstrip line and square ring), an appropriate combination of them forms the initial element with a bandpass feature. In addition, the PIN diode is placed in the middle of the microstrip line so that the element’s resonant frequency varies with its ON/OFF state. Full-wave simulation shows the design of dual-band RFSS operating at 8.8 GHz and 10.4 GHz, which validates the proposed CM design.