Multisection step-impedance modeling and analysis of broadband microwave honeycomb absorbing structures

Abstract A multisection step-impedance honeycomb absorbing structure is investigated both theoretically and experimentally. Excellent intrinsic impedance matching and low reflection are realized by providing a step-impedance transition between air and metal in the microwave band. The wideband absorption mechanism of the honeycomb absorbing structure is analyzed using a step-impedance model, and the particle swarm optimization algorithm is used to obtain the optimal step impedance. Two absorbing structures were simulated: The double-layer structure had an absorption frequency band of 3.9–12.4 GHz and a thickness of 9 mm, and the triple-layer structure had an absorption frequency band of 2.2–12.4 GHz and a thickness of 15 mm. The measured reflectivity values were consistent with the calculated results, thereby confirming the validity of our designs for the absorbing structure.