A coupling compensation method to improve the absorption effect at wide angles

Abstract

In this paper, we proposed a coupling compensation method based on equivalent transmission line model to solve the deterioration of absorption performance of the electromagnetic absorber under large incident angle for TE polarization. By adding decoupling compensation layer determined by the proposed method on the original single-layer structure, the issue of inadequate impedance matching has been addressed. The absorption performance under target angle was improved while maintaining that of the original structure under normal incidence. Compared to the original structure, the 90% absorption bandwidth is expanded from 9.6–10.6 GHz to 4.3–12.4 GHz, and the relative absorption bandwidth is increased from 9.9% to 97% under TE-polarized waves with the target incident angle ($50°$). While the performance of absorption under TM-polarized waves with the target angle remains nearly unchanged, thereby indicating that both polarization achieve a wide absorption bandwidth under incidence of $0°$ and target angle. Additionally, the proposed method effectively enhances the absorption not only under the target angle, but also in close proximity to it. The proposed method is proved by full-wave simulation and experimental measurements. This work offers enhanced flexibility for diverse scenarios, including the option of a detachable absorber.