Simulation design of S-band waveguide-type limiter and the effect of structural changes on S-parameters

This paper investigates the design methodology of an S-band waveguide limiter and the impact of resonant gap dimensions on S-parameters through electromagnetic simulation. During the design process, COMSOL software's parametric scanning was employed to optimize and determine the resonant window dimensions. Concurrently, the study explored how different resonant gap combinations (Frustum-Frustum Type, Biconical Type, Conical-Frustum Type) and variations in resonant gap dimensions (electrode clearance, resonant gap width, the upper top of the frustum) affect the resonance point and bandwidth of the S-parameters. Simulation results demonstrate the bandpass filtering performance of the waveguide-type limiter at low power levels and reveal the variation patterns of S-parameters under different structures and dimensions, providing valuable experience for subsequent engineering designs. The waveguide-type limiter designed in this paper exhibits characteristics such as insertion loss below 0.5 dB, maximum isolation of 40 dB, and high capacitance.