Dual-Polarized Bandpass and Band-Notched Frequency-Selective Absorbers Under Multimode Resonance

Two novel dual-polarized frequency-selective absorbers (FSA) are proposed based on two-layered structures under multimode resonances. Each FSA consists of a two-layered metal structure with an air gap in the middle. At the top layer, a hybrid resonator is applied to generate a wide absorption band and a stop/passband. At the bottom layer, two different types of structures are separately applied to perform the opposite senses of bandpass and band-notched filtering for the final FSAs. Moreover, the design strategies were examined using the corresponding equivalent circuit models. The resultant absorbers have the thickness of only approximately 0.08 λ
_L
at the lowest operating frequencies and exhibit wide operating bands of over 100%. To demonstrate this approach, two prototypes of the proposed absorbers were fabricated and tested, and reasonable agreement between the simulation results and experimental data was obtained.