Design and mathematical analysis of a metasurface-based THz bandpass filter with an equivalent circuit model

This paper presents successive studies of single-, double-, and triple-layered metasurface-based bandpass filters along with their equivalent circuit modeling and mathematical analyses. A triple-layered bandpass filter operating in the THz region is reported exhibiting flattop passband response while maintaining transmission of more than 95% over the entire passband starting from the design of a single-layered bandpass filter configuration. A stepwise mathematical analysis is carried out for the single-layered structure and compared with the simulation data, where the two results have been found in good agreement. Thereafter, the study is extended for double- and triple-layer bandpass filters. The triple-layered structure offers a very steep transition between passband and stopband with noise-free background, and thereby offers a potential candidate for 6G communication.