Design of an Ultra-Wide-Angle Metamaterial Absorber on an Artificial Magnetic Conductor Substrate Based on the Reciprocity Theorem

An innovative design method of wide-angle metamaterial absorber based on antenna reciprocity principle is proposed. According to the antenna reciprocity principle, a wide-angle metamaterial absorber can be designed by loading a matching resistor at the feed point of a wide-beam antenna unit. First, the feasibility of designing a wide-angle metamaterial absorber using a wide-angle scanning array is theoretically analyzed from the perspective of antenna scattering field angle theory. Subsequently, a wide-beam element is designed based on the image principle, and the design of an ultra-wide-angle metamaterial absorber is achieved by loading an appropriate resistor at the feed port of the element. Simulation results show that the designed absorber maintains more than 80% absorption efficiency for TE waves in the range of 6.5 GHz to 7.09 GHz and for TM waves in the range of 3.94 GHz to 5.44 GHz at an incidence angle of 80°.