Analysis and simulation of X-band high-power microwave generation based on T-shaped four-period slow-wave structure

Abstract

This study conducts an optimized design and a comprehensive high-frequency theoretical analysis on a T-shaped, four-period resonant slow-wave structure. By employing the image theory, the T-shaped waveguide unit was translated into an equivalent ridge waveguide configuration. The high-frequency characteristics of the equivalent ridge waveguide were analyzed using equivalent circuit theory, leading to a resonant frequency and structural analysis of the T-shaped waveguide. The analysis has confirmed that in the ridge waveguide, starting from the second-highest order mode, the frequency points of the even-order modes exhibit a strong correspondence with those of the T-shaped waveguide; however, the odd-order modes lack a corresponding mode in the T-shaped waveguide, as they do not fulfill the electric boundary conditions dictated by the image method. On this basis, a T-shaped four-period resonant slow-wave structure was constructed, and its dispersion characteristics were analyzed to determine the resonant modes and frequencies, as well as the range of mode synchronization voltages. Simulations were subsequently performed to validate the effectiveness of the relativistic extended interaction radiation source, which incorporated the novel T-shaped periodic resonant slow-wave structure. Advanced three-dimensional particle simulations, in conjunction with optimization techniques, facilitated the achievement of a high-power microwave output at a frequency of 9.8 GHz, delivering an average power of 71.4 MW. This output was attained under conditions of a 448 kV beam voltage, 400 A beam current, and a 0.4 T uniform axial magnetic field, which resulted in an electron efficiency of 39.8%. This structure, characterized by the T-shaped waveguide, was demonstrated to be capable of producing high-efficiency, high-power microwaves with fewer periods, presenting a compact and efficient solution for the generation of high-power microwaves in advanced scientific applications.