Heterogeneous Reconfigurable Frequency Selective Surface With Ultrawide Range Performance

In this article, a series-type equivalent circuit model (ECM) is proposed to effectively broaden the modulation range and capability of reconfigurable frequency selective surface (RFSS). Correspondingly, a heterogeneous RFSS unit, which consists of a coplanar arrangement of two units with different dimensions and different resonant frequencies is designed. The designed multifunctional single-polarized RFSS unit allows for an ultrawide range of tunable transmission passbands and efficient reflection and shielding behavior over the entire frequency range by rationally configuring the active elements parameters. In the transmission state, the relative bandwidth (RBW) of the tunable range of transmission poles is significantly increased to 130.9%. In the shielding state, the proposed unit remains transmission coefficient $\vert {S}_{21}\vert \lt -10$ dB over the entire frequency band. Utilizing the robust reconfigurability, the proposed RFSS unit can achieve excellent angular stability additionally. The prototype is fabricated and measured to verify the effectiveness and feasibility of the design. This work greatly expands the ability of RFSS to modulate electromagnetic waves. It broadens application scenarios of broadband antenna by providing a new feasible solution for achieving superior performance in multifunctional RFSS.