An Improved X-Band Triaxial Klystron Amplifier for Gigawatt Long-Pulse High-Power Microwave Generation

Abstract

Triaxial klystron amplifier (TKA) is prom- ising for coherent power combining of high-power microwaves (HPMs) in high-frequency bands. In this letter, we present an improved X-band TKA to generate gigawatt long-pulse HPM radiations. By increasing the intrinsic quality factor of the input cavity, the seed microwave loss is reduced significantly. The beam loaded quality factor of the input cavity is increased to enhance the gap voltage and, moreover, to strengthen the electron beam modulation. In addition, a double-gap output cavity is designed on the one hand to increase the radio-frequency power capacity and on the other hand to improve the beam-wave power conversion efficiency. The improved TKA is demonstrated to be capable of producing the HPM X-band radiation typically with power of 1.1 GW and pulse duration of 105 ns in experiments. Furthermore, the phase of the generated microwave is locked by the seed signal over more than 90 ns.