Broadband Microwave Absorber with a Double-Split Ring Structure

In this paper, we present a novel broadband microwave absorber. Each unit in the metamaterial consists of a layer of dielectric material sandwiched between two layers of metal patches. Due to metal-dielectric-metal structures consist of symmetric resonators that have low co-polarization and cross-polarization as absorbers, the upper metal layer comprises a novel double-split ring resonator and a central octagonal ring pattern. Our simulation results show that the absorption of the proposed absorber is above 90% in the frequency range from 5.7 to 13.1 GHz. The absorption bandwidth over which the absorptivity exceeds 90% is approximately 7.4 GHz. The calculated relative bandwidth of 78.1% meets the standard for ultra-broadband absorption, and thus has prospects in applications. There are four main resonance frequencies at 6.07, 9.18, 12.75, and 13.11 GHz. And, the absorptivity is not significantly affected by the variation of the incident angle. We find that the resonance phenomenon becomes increasingly prominent as the incident wave frequency increases.