A Low-Profile Energy Selective Surface With Ultra-Wide Absorption Band

A low-profile energy selective surface (ESS) with an ultra-wide absorption band is proposed in this article. It consists of a switchable layer and an absorptive layer. The switchable layer uses p-i-n diodes to adaptively adjust the operating mode. When the incident wave power is low, the ESS operates in transmission mode. It behaves as a bandpass frequency selective surface (FSS) having an ultra-wideband (UWB) absorption out of the passband. As high-power microwaves (HPMs) are incident, the ESS changes to shield mode. The HPM in the passband are reflected, while those out of band are absorbed. As a result, stealth and shielding are realized at the same time. By loading metal patches on both sides of the dielectric substrate, the number of transmission zero out of the passband is increased. As a result, the shielding and absorption bandwidth (AB) are widened. The wide absorption band can absorb detection signals before the diodes are triggered and provide a shield in advance. The experimental results show that the ESS has an insertion loss (IL) of 0.6 dB at 3.8 GHz and an absorption band range of 5.97–13.97 GHz in transmission mode. While in shield mode, a shielding effectiveness (SE) of 13 dB and an absorption band range of 5.74–12.82 GHz are obtained. This novel ESS simultaneously achieving high-power electromagnetic (EM) protection and stealth in a wide band has various prospects of applications in EM protection, EM compatibility, and EM interference along with stealth technology.