A harmonic multiplying gyrotron traveling wave amplifier at Ka band developed in IECAS

The works related to harmonic multiplying gyrotron traveling wave amplifier were ever reported by us in IRMMW2006 and IVEC2007, which showed that there were some contradictions between output power and band-width.^{[1, 2]} In [1], the output frequency bandwidth of more 500 MHz can be reached at output pulse power of only 10.07~12.88kW. In [2], output pulse power can be increased to 25kW with very narrow bandwidth. Because of using harmonic multiplying, the resonant circuit is usually used to increase the coupling between fundamental and harmonic. However, it will decrease operating bandwidth. In this article, a new method is utilized for enhacing output power and improving bandwidth.