Representation of coupled-cavity slow-wave structures by equivalent circuits

The slow-wave structures used in high-power travelling-wave tubes may be represented by equivalent circuits. It is shown that, by a suitable choice of equivalent circuit parameters, a good fit can be obtained between calculated curves and measured data points. The equivalent circuits may be used to represent the slow-wave structure in computer models of high-power travelling-wave tubes. If empirical relationships can be established between the equivalent circuit parameters and the dimensions of the slow-wave structures, then it will become possible to optimise the designs of high-power TWTs without the need for extensive series of cold test measurements.