An Ultra-Broadband Energy Selective Surface Design Method: From Filter Circuits to Metamaterials

A novel design method for ultra-broadband energy selective surface (ESS) is presented in this article based on the equivalent theory from filter circuits to metamaterial units. This method provides a new way of designing ESS in ultra-broadband with low insertion loss (IL) and high shielding efficiency from the perspective of filter circuit topology. It is illustrated and verified with a three layer ultra-broadband ESS. Firstly, a third-order filter with a switching bandpass to bandstop in C to Ku-band is designed and optimized. Then, the filter is mapped to a physical model of a three-layer ESS which has a nonlinear transmission response for low-intensity radiation field (LIRF) and high-intensity radiation field (HIRF) in C/X/Ku-band. The three ESS prototypes are fabricated and measured in three different band waveguides to prove the design method of the ESS proposed in ultra-broadband. Simulated and measured results demonstrate that low IL and high shielding efficiency at the same time can be obtained under low and high incident power levels, respectively, where the 1 dB loss and 23 dB shielding bandwidth cover from 5.4 to 14.45 GHz. Furthermore, the IL is less than 0.5 dB in the frequency band of 5.45–13.8 GHz and maximum shielding effectiveness (SE) reaches 25 dB at 10 GHz.