Simulation-driven optimization strategies for radar absorbing sandwich structures and application to RCS reduction of all-movable rudder

Addressing the practical demand for microwave absorbers in application, this research introduces a novel microwave absorbing sandwich structure that integrates functionally graded microwave absorbing face sheets with a standard octet truss lattice core. Unlike conventional approaches that rely on complex core geometries, the proposed method shifts the design focus to the multilayered face sheets, which are made of a graphene-filled composite. Within these sheets, the volume fraction of the graphene filler is optimized to achieve enhanced impedance matching and broadband absorption. Additionally, a particle swarm optimization (PSO) framework is implemented to maximize the effective absorption bandwidth, resulting in a structure that fully covers the Ku-band with a reflection loss below −10 dB, which is subsequently validated through full-wave simulations. Furthermore, the optimized absorber is applied to an all-movable rudder, and its radar cross section (RCS) is systematically evaluated across six frequency bands (P, L, S, C, X, Ku) and multiple deflection angles. Simulations confirm significant RCS reduction, particularly in the Ku-band, demonstrating the absorber’s practical efficacy for stealth rudder. This research provides an engineering solution for stealth structural design using simulation analysis approaches.