Design of S-Band SLED Pulse Compression System

The combination of conventional klystrons and microwave pulse compression systems is a promising method for generating high-power microwaves. This paper presents the design of an S-band SLED pulse compression system, primarily composed of a 3dB coupler, two energy storage cavities, and input coupling structures. The system features simple principles, compact structure, and high power capacity. The 3dB coupler adopts an H-type structure with two stepped structures on the input/output waveguide walls to achieve impedance matching and equal power division. Simulation results show that the reflection coefficient at Port 1 and the isolation coefficient at Port 4 are both below -34 dB, while the coupling coefficients at Ports 2 and 3 are -3 dB and -3.01 dB, respectively, with a phase difference of 89.82°. The energy storage cavities utilize cylindrical $\text{TE}_{01}$-mode cavities with high power capacity and low loss, operating in the $\text{TE}_{015}$ mode at a resonant frequency of 2.856 $\text{G H z}$ and a quality factor of approximately $\text{1 3 0, 0 0 0}$. The cavity dimensions are designed to suppress competing modes. Under room temperature and atmospheric pressure, the S-band SLED system achieves a power capacity of 334 kW and an experimental output pulse power of 1.5 MW, corresponding to a power gain of approximately 4.5 times.