A s-band 2.5 mw high power broadband klystron

In this paper, the design considerations of a high-efficiency high-gain broadband klystron are described. Its buncher has been studied by using small signal gain and large signal efficiency programs. With small gain greater than 50’dB, the buncher bandwidths of 10% and 10–15% can be obtained for 7 and 8 cavity klystrons respectively. The design methods and measured results of output circuits of two types are introduced. The bandwidths of the filter type and the overlapping mode two gap cavity output circuits are about 7.5–10% and 10–12% respectively. Two types of S-band broadband klystrons with the two respective output circuits described are constructed and tested, and the one with the former output circuit has 1 dB equi-drive bandwidth of 7.5% with an efficiency of 38% and a gain of 43 dB, while the other with the later output circuit has 1 dB equidrive bandwidth of 10%. Their output power is greater than 2.5 MW.