Low-power wide-bandwidth klystron

Abstract

A low-power wide-bandwidth klystron comprises a cathode having an electron emitting surface capable of emitting an electron beam and a collector spaced from said cathode and designed to collect the electron beam emitted from the cathode. An anode is disposed between the cathode and the collector in order to channel the electron beam into a series of drift tubes that define the electron beam path between the anode and the collector. The drift tubes define gaps in which the input cavity and output cavity interact with the electron beam. The input cavity velocity modulates the electron beam by way of a radio frequency input signal and the output cavity extracts the amplified radio frequency signal from the electron beam. The drift tubes may define additional gaps between the input cavity and output cavity for intermediate cavities that would provide additional amplification. A voltage potential, positive with respect to the cathode voltage potential, is applied to the anode in order to draw the electron beam from the emitting surface of the cathode and into the drift tubes. The anode voltage potential is much larger than required for the desired output power. The output cavity is overloaded by providing it with a load conductance that is at least twice that required for optimal klystron power output. A voltage potential, positive with respect to the cathode voltage potential, is applied to the collector, but the voltage potential difference between the cathode and the collector may be at most one half of a corresponding voltage potential difference between the cathode and the anode.