High-Power Mechanical Waveguide Phase Shifter: Electromagnetic Resonance Analysis and Protection Design

Mechanical waveguide phase shifters (MWPSs) serve as crucial components of phase adjustment in high-power microwaves (HPMs); however, despite their widespread use, the potential resonance issues require further investigation. This study analyzes the electromagnetic (EM) resonance characteristics of high-power MWPS (HPMWPS), thereby constructing a generalized equivalent circuit model of MWPS to predict the resonant frequencies. An analysis revealed three resonance types in HPMWPS: over-mode, slot, and cavity. The slot resonance generates a violent field concentration phenomenon that limits its application in HPM. Based on such resonance characteristics, two choke pistons with double-sided hollowed trapezoidal slots are proposed. Simulations and experimental results revealed that the proposed method can accurately and efficiently predict the resonance of HPMWPS, and the designed choke piston can effectively suppress microwave leakage and avoid resonance and has the added advantage of compactness.