A Miniaturized Absorber Frequency Selective Surface With Good Angular Stability

A miniaturized absorber frequency selective surface (MAFSS) is proposed in this letter. The proposed absorptive frequency selective surface is mainly composed of two parts: the upper three-dimensional (3-D) absorbing structure and the bottom two-dimensional (2-D) frequency selective surface. The upper structure contains two elliptic absorbing structures, which provide a wide absorbing band over 12-18 GHz. The bottom structure includes an FSS, which acts as a bandpass filter in the transmission band (3.9-5.1 GHz). The unit-cell dimension of the MAFSS is 0.11λ0 × 0.11λ0 × 0.071λ0 (λ0 is the wavelength of the transmission band in free space). Being in relative small size, the presented MAFSS can effectively avoid grating lobes and remain stable when the angle of incidence wave changes. Finally, the simulated results of the presented designs are verified by the practical samples and measurements.