High Frequency Characteristics Analysis of Rectangular Waveguide Grating

In order to overcome the limit of Single-Mode Approximation (SMA), this paper adopts a new method that when expressing the fields inside the grooves, the higher orders are retained as an infinite sum of standing eigen-waves. The dispersion relation is obtained by field-matching method, while the coupling impedance is subsequently obtained from the relevant equations. A lot of numerical computations and analysis are done for rectangular grating slow-wave system. And the effects of the geometrical characteristics of the grating are analyzed. Finally, rectangular waveguide gratings at 3 cm band and 8 mm band are designed and measured, experimental values match theoretical values very well.