Experimental Validation of a Frequency-Selective Surface-Loaded Hybrid Metamaterial Absorber With Wide Bandwidth

The achievement of wide absorption bandwidth for a single-layer metamaterial absorber remains a challenge. In this letter, a frequency-selective surface (FSS), single-substrate layer, broadband metamaterial absorber is investigated theoretically, experimentally, and by simulation in the frequency range of 2-18 GHz. Simulations of the reflection coefficient of the absorber with different substrate dielectric thicknesses, FSS thicknesses, and FSS dimensions indicate that there exist optimal values for the absorber design. The measured results from a fabricated prototype are in close agreement with the simulations, suggesting the effectiveness of the structure for actual electromagnetic applications. The fabricated absorber with thickness 2.0 mm has a minimum reflection coefficient of -29.0 dB at 12.2 GHz. The -10 dB absorption bandwidth is 7.5 GHz in the range of 8.5-16 GHz. Effective complex electromagnetic parameters are extracted to quantitatively understand the absorption. A miniaturized structure, single-substrate layer, simple geometry, and wide bandwidth are some of the key features of the proposed metamaterial absorber.