Wide-angle and wideband microwave absorber based on a honeycomb structure integrated with geometrically tapered resistive patterns

Modern electromagnetic absorbers must maintain low reflection over wide angular and frequency ranges for practical applications. This article presents a novel honeycomb structure integrated with geometrically tapered resistive patterns (HS-GTRP) for wide-angle and wideband microwave absorption. By utilizing geometric variations to establish a continuous impedance gradient, the proposed structure achieves excellent impedance matching and stable absorption performance over a wide range of oblique incidence angles. An effective-medium model is first established to clarify the relationship between the geometry of the resistive patterns and the resulting tapered permittivity profile. Subsequently, a nonuniform transmission-line model based on a differential formulation is developed to calculate the reflectivity under oblique incidence. The calculated results agree well with the simulation results, validating the model and demonstrating wide-angle impedance matching. The proposed composite absorber, featuring stable geometrically tapered resistive patterns realized via screen printing, was fabricated and experimentally validated. The fabricated absorber exhibits reflectivity below -10 dB from 3.57 to 18 GHz for both TE and TM polarizations and maintains this performance up to an incidence angle of 45°. The good agreement among theoretical analysis, full-wave simulations, and measured results confirms the effectiveness of the proposed design strategy.