Wide-angle microwave absorption performance of polyurethane foams combined with cross-shaped metamaterial absorber

Abstract

Abstract A cross-shaped metamaterial absorber (CSMMA) has been introduced to integrate with two-layered polyurethane foam absorbers (PUFAs). By incorporating with CSMMA, microwave absorptive performance of the proposed PUFAs in 8–18 GHz has been remarkably improved for various oblique incident angles under the transverse electric (TE) and transverse magnetic (TM) waves. For the TE wave, the effective bandwidths of −10 dB reflection loss for the PUFAs incorporated with CSMMA increase by 0.85 GHz, 1.15 GHz, 1.25 GHz, 1.50 GHz and 1.70 GHz for 0°, 15°, 30°, 45° and 60°, respectively. As for the TM wave, the effective bandwidths of −10 dB reflection loss for the modified PUFAs by CSMMA rise by 0.85 GHz, 1.10 GHz, 1.20 GHz, 2.85 GHz and 2.90 GHz for 0°, 15°, 30°, 45° and 60°, respectively. The proposed PUFAs optimized by CSMMA could operate well at incident angles ranging from 0° to 60° for both TE and TM waves. In addition, the different variation rules of absorption peak intensity of CSMMA have been revealed through the magnetic field distributions under TE and TM waves. Results indicate that PUFAs combined with CSMMA can be utilized for microwave absorbers adapting to both TE and TM waves at various oblique incident angles.