Wideband Dual-Polarized Microwave Absorber at Extremely Oblique Incidence

In this article, a novel method for developing a dual-polarized broadband microwave absorber (MA) for use at an extremely oblique incidence angle is presented. A detailed theoretical analysis is performed and formulas are derived to obtain the required relative permittivity and permeability tensors to achieve dual-polarized absorption at an arbitrary oblique incidence angle. As a proof of concept, a broadband dual-polarized MA operating at an oblique angle of$75~{}^{\circ }$is designed whose unit cell consists of a pair of rectangular patches and a rectangular loop embedded with four resistors. A prototype is fabricated and measured for verification. Both the measured and simulated results demonstrate that the proposed MA achieves more than 90% absorption within a broad frequency with a relative bandwidth of 61.2% for both transverse electric (TE) and transverse magnetic (TM) polarizations at an extremely oblique incidence angle of$75~{}^{\circ }$.