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 lambda(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.