Design of a Wideband Dual-polarization Switchable Active Frequency Selective Surface

Based on PIN diodes, a broadband dual-polarized active frequency selective surface (AFSS) with switchable operating modes is designed in this paper. Three metal layers are sandwiched between two F4B substrates to form the model. Four PIN diodes are placed on the metal layer to enable the switching function between reflection and transmission modes. Moreover, the interaction of the metal layers produces second-order resonance, significantly enhancing the transmission bandwidth. When the AFSS operates in the reflection mode, electromagnetic (EM) waves are completely shielded from 0 to 8.24 GHz. In the transmission mode, the transmission bandwidth ranges from 2.96 to 4.6 GHz, and the relative bandwidth is 43.4%. The structure's equivalent circuit model (ECM) is proposed, and the switching principle of AFSS is analyzed based on this. The simulated results show that the AFSS achieves a dual-polarized wideband switching function and maintains stability for EM waves at a 30° oblique incidence, indicating its great potential in stealth technology.