STUDY AND INVESTIGATION LEADING TO THE DESIGN OF BROADBAND HIGH POWER KLYSTRON AMPLIFIERS

Abstract

Abstract : The purpose of this program is to investigate methods for improving the bandwidth capabilities of high-power klystron amplifiers. The objective is a 1 db bandwidth improvement of at least fifty percent over the current state of the art. Particular emphasis is being placed on the study of extended- interaction resonators, and the possible optimization of these resonators through the use of mode overlapping. In this report, the results of the continued investigation into the effects of mode overlapping in two-gap extended-interaction resonators are presented. An emphasis was placed on the study of the sensitivity of the resonator's frequency response to changes in the beam voltage, which seemed to be a major drawback of resonators with overlapping modes. It is shown that this sensitivity can be minimized by synchronizing the beam with the pi mode. One theoretical example is cited wherein a beam voltage variation of more than fifty percent causes only small changes in the resonator's response and bandwidth. Equations are derived for a computer program which will calculate the small-signal gain and phase response of klystrons employing extended-interaction resonators with overlapping modes. The gain equation is written in terms of the circuit admittance and electronic admittance matrices of each resonator, and the transfer admittance matrices between resonators. The equations were derived for the particular case of two-gap resonators, but the method is generally applicable to resonators with any number of gaps.