Frequency Selective Surface Composites With Honeycomb Absorbing Structure for Broadband Applications

A novel composite of an area-coated grading honeycomb (ACGH) structure and a frequency selective surface (FSS) was theoretically and experimentally investigated for use as broadband microwave absorbing. The main difference from the traditional FSS absorber was that the aramid honeycomb was replaced by an absorbing honeycomb structure, which increased the absorption bandwidth by suppressing the half-wavelength total reflection point. The physical mechanism was analyzed using an equivalent circuit model and the impedance range diagram. The designed absorber had a −10 dB fractional absorption bandwidth of 154.3% from 2.0 to 15.5 GHz, and it had a thickness of
$0.113\lambda _{L} $
at the lowest frequency. The ACGH structure was integrally formed to ensure high structural strength. Reflectivity measurements were consistent with calculated values, validating the design principle and preparation technique for the composite.