Multi-Band Absorptive Frequency-Selective Reflection Structures

Multiband absorptive frequency-selective reflection (AFSR) structures are proposed in this paper. The structures exhibit multi-reflection bands within a wide absorption band; such performance is accomplished by cascading a multiband bandstop 3-D frequency-selective structure (3-D FSS) with a wideband absorber. Two AFSR structures are designed and simulated. The first structure has dual-reflection bands, while the second structure exhibits tri-reflection bands. A commercial absorber, Eccosorb
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FGM-125, is utilized because it is thin (thickness = 3.2 mm) and has a wide absorption band (2 - 12 GHz). This lossy material is termed as ECCOSORB FGMU-125 in CST2014. Under oblique incidence, stable dual- and tri-reflection bands with out-of-band absorption are accomplished.