Four-Mode Switchable Frequency-Selective Surface Featuring Wideband and Angular Stability

This letter proposes a switchable frequency-selective surface with wide-band and angle-stable characteristics, which could independently manipulate the TE and TM incidences through four modes. Distributed compensation capacitors are designed to solve the problems of unequal impedances and inconsistent responses under different polarizations caused by the asymmetric structure. It also helps improve the miniaturization and oblique-incident performances of this work. Additionally, the transmission responses and field distributions of each layer are studied to verify the proposed principle. The operating mechanism under different waves is also analyzed through two equivalent-circuit models. The results show that the design achieves stable transmission and shielding behaviors from 0° to 55° incidences. In the transmission state, a passband of 32.9% is realized with a minimum insertion loss of 0.15 dB, while the shielding performance can be observed from low frequencies to 10 GHz. Finally, a prototype is fabricated, and reasonable measurement results are obtained.