Method for suppressing second and higher harmonic power generation in

Abstract

A method for suppressing second and higher harmonic power generation in a klystron is described. The klystron includes a series of cavities that are connected to a series of connecting drift tubes, and one or more waveguide loads are placed on selected ones of the drift tubes or cavities, for reducing the second and higher harmonic power by causing it to be loaded out progressively, at predetermined discrete intervals. In the preferred embodiment, the inner diameter of the drift tubes is such that the cutoff frequency is above the fundamental operating frequency of the klystron, which will allow frequencies greater than the fundamental frequency, and particularly the second harmonic frequency, for example 22.848 GHz, to propagate. In one example, each of the four pre-selected drift tubes is loaded with two generally diametrically oppositely positioned waveguide loads. In another example, each of four drift tubes is loaded with three equidistally positioned waveguide loads. In yet another design, the drift tubes and/or cavities are loaded with encapsulated ceramic assemblies having lossy ceramic cylindrical segments that are inductively coupled to their corresponding drift tubes and/or cavities by means of inductive couplings. These segments can assume a variety of geometrical shapes.