A Frequency-Selective Surface Rasorber Based on Four Functional Layers

In this article, a frequency-selective surface (FSS) rasorber based on four metallic FSS functional layers is proposed. The rasorber consists of two metallic FSS absorption layers, two metallic FSS transmission layers, and four corresponding dielectric isolation layers. The top absorption layer and third absorption layer are applied to generate a wide absorption band at high frequency and low frequency, respectively. The second and bottom transmission layers are adopted to generate a low-pass transmission band and bandpass transmission band, respectively. The multilayer structure of the rasorber guarantees the great span, broad bandwidth, and stable scattering characteristics. Moreover, we adopt the equivalent circuit model (ECM), surface current distribution, and loss distribution to comprehend the physical mechanism of the rasorber. The simulated results show that the transmission is -0.67 dB at 6.5 GHz, and the reflection below -10 dB ranges 1.5-4.6 and 9.2-13.7 GHz. To validate our design, we fabricated and measured the prototypes, and the measurement results show reasonable agreement with the simulated results.