Investigation on High-Efficiency Beam-Wave Interaction for Coaxial Multi-Beam Relativistic Klystron Amplifier

Abstract

To significantly improve the electronic efficiency of coaxial multi-beam relativistic klystron amplifier (CMB-RKA), the physical process of beam-wave interaction and parameters that affect efficiency was studied. First, the high efficiency of beam-wave interaction was discussed by simulating the efficiency versus the parameters (frequency of cavity, drift tube length between cavities, and external quality factor of output cavity), in the one-dimensional (1-D) large-signal simulation software. Moreover, the further physical process of beam-wave interaction was analyzed through simulating the current modulation factor and the number of particles at the entrance of the output cavity, in the three-dimensional (3-D) particle in cell simulation software. Last, with the optimal parameters in 3-D simulations, the CMB-RKA, which has 14 electron beams with a total current of 4.2 kA (14 × 300 A), can generate an output power of 1.02 GW with a saturation gain of 55.6 dB and an efficiency of 48.7%, when beam voltage is 500 kV, which indicated the CMB-RKA can achieve high efficiency for high-power microwave radiation.

A Novel Bandstop Filter Based on Two-Port Coaxial Cavities for the Installation of Metallic Mode Stirrers in Microwave Ovens

“…In this work, we use two-port high power coaxial cavities as resonators and coaxial lines to couple them in a cascade configuration. Sun et al [22] demonstrated that an equivalent lumped model of coaxial cavities can be realized using a parallel tank of resistance, inductance, and capacitance, and that this type of cavity can function as a bandstop filter. In [23], a two-port resonant coaxial stub was analyzed, and designing curves for band-pass filters was shown to aid in the design process.…”

High-Frequency Vacuum Electron Devices

“…Klystrons often have a higher power, higher gain and higher efficiency than TWTs, which is addressed two papers in this issue. One paper [12] performs an investigation of the high efficiency of a coaxial multi-beam relativistic klystron. PIC simulation is used to analyze the beam-wave interaction physical process and optimize the high-frequency parameters.…”