High-Power Ultra-Wideband Operation of the JINR-IAP FEM-Amplifier

Powerful high-efficiency FEM -amplifiers operating over Ka frequency range have been developed in collaboration between IAP RAS and JINR. Potential to reach a broad amplification band in different regimes of e-beam/RF -wave interaction was investigated theoretically and examined in the series of experiments. In the FEM with a regular wiggler operating in the so-called grazing incident regime, output power of 20 MW was simulated in the frequency range of 30 ± 2 GHz. In the experiments, the designed power level and the instantaneous band of about 1 GHz (restricted by the tuning band of the driving magnetron) were achieved. According to the simulations, the use of original regime of non-resonant trapping in tapered wiggler allows enhance in the output power up to 35 - 40 MW with simultaneous widening of the amplification band. In the experimental realization of this novel FEM scheme, an output power on the level of 25 - 27 MW was measured when various magnetrons with the frequencies in the range from 29 GHz to 35 GHz were utilized to drive the amplifier.