A Ku-band phase-locked coaxial relativistic Cherenkov generator with low guiding magnetic field

A Ku-band phase-locked coaxial relativistic Cherenkov generator with a low guiding magnetic field is presented. Owing to the use of the combined periodic double-corrugation slow-wave structure, the quasi-TEM mode exhibits a strong axial electric field at the center of the beam tunnel. As a result, the electron beam can achieve effective beam–wave interaction without proximity to the SWS surfaces, allowing the electron beam with a larger envelope and, therefore, reducing the demand for strong guiding magnetic fields. Two single-gap cascaded pre-modulation cavities are used to reduce the demand for the injected signal and to improve the power ratio of the output microwave to the input signal. Particle-in-cell simulation results show that, under a guiding magnetic field of 0.65 T, an injected signal with a power of 5 kW can lock the frequency and phase of a 966 MW output microwave, where the bandwidth is about 60 MHz and the phase instability is within ±2°. In addition, the efficiency is about 40%, and the power ratio of the output microwave to the input signal is ∼53 dB.