A Novel Frequency-Selective Surface-Enhanced Composite Honeycomb Absorber with Excellent Microwave Absorption

Multifunctional structures with excellent wave-absorbing and load-bearing properties have attracted much attention in recent years. Unlike other wave-absorbing materials, honeycomb wave-absorbing materials have appealing radar absorption and mechanical properties. However, the existing honeycomb wave-absorbing materials have problems such as narrow absorption band and poor compression resistance. In this study, a novel frequency selective surface-enhanced composite honeycomb absorbers (FSS-CHAs) are fabricated by combining a honeycomb structure with wonderful load-bearing capacity and FSS through screen-printing and inlay-locking techniques. After reflectivity measurements, the effective absorption band (RL < -10 dB) of CHA is 6.25-17.47 GHz and a bandwidth of 11.22 GHz, the effective absorption band of the FSS-CHA is 3.96-18 GHz and a bandwidth of 14.04 GHz, 25.13% improvement compared to the CHA, the mechanism of wave absorption is explained using transmission line theory. The simulation results show that the wide bandwidth is due to the different absorption mechanisms of FSS-CHA at low and high frequencies. The compression test shows that the compression strength of FSS-CHA is 17.10 MPa. In addition, FSS-CHA has a low cost of only USD 270.7/m². This study confirms the possibility of combining FSS with radar-absorbing honeycombs, which provides a reference for the design of future broadband wave-absorbing structures, offers a novel approach to integrating FSS with CHA, and aims to optimize their efficacy and utility in stealth technology.