Dispersion characteristics-based asymmetric frequency selective rasorber using spoof surface plasmon polariton mode

The present study introduces a comprehensive theoretical design that demonstrates the unique advantages of the Spoof Surface Plasmon Polariton (SSPP) mode in achieving the Absorption-Transmission Window (A-TW) effect, thereby enabling the perfect integration of the SSPP mode with the Frequency Selective Rasorber (FSR). This paper analyzes the main reasons for the coexistence of electromagnetic wave (EMW) transmission and absorption effects, thereby confirming the confining effect of localized fields in the SSPP mode on EMW. Additionally, the distinct dispersion characteristics of the structure are investigated, showcasing the remarkable capability of dispersion engineering in generating customized absorption bands. The results indicate that the aforementioned FSR exhibits absorption abilities of over 90 % for positively incident EMWs in the frequency ranges of 1.44 ∼ 2.04 THz and 4.65 ∼ 5.44 THz, while also making constructive contributions to the formation of the transmission window (TW) in 2.61 ∼ 4.07 THz. Exploring the asymmetric response of EMWs reveals that the FSR exhibits a pseudo-Reflection-Transmission Window (R-TW) effect when excited by reverse-propagating EMWs. This paper proposes an FSR based on the SSPP mode, exhibiting asymmetric EMW response, and hopefully contributes a new perspective for the application and theoretical analysis of the SSPP mode.