Design of a Broadband Energy-Selective Surface With Ultrahigh Shielding Efficiency

In this letter, a novel high-performance energy-selective surface (ESS) is demonstrated for enabling defense against extremely high-power microwaves. The metasurface is designed with periodic metallic textures and loaded nonlinear PIN diodes. The ultrahigh shielding performance is achieved through cascades of combined resonant circuits and an optimized coupling scheme. The scheme is based on a backward-propagation neural network algorithm, which is introduced into the mapping of the equivalent circuit and electromagnetic structures. Simulations and experiments show that the proposed ESS can achieve an insertion loss of less than 1 dB over a bandwidth of 40%. Specially, the shielding efficiency of more than 40 dB has a relative bandwidth of almost 200%. Meanwhile, this design can realize an angular stability of more than 60° under TE/TM dual-polarized electromagnetic wave incidence. Such a design offers an excellent solution for electronic device protection from ultrahigh-power microwaves with wide incident angles.