Calculation of coupled-cavity TWT performance

A method of calculation of coupled-cavity TWT performance which is programmable for fast and economical calculation on a time-sharing computer is presented. The tube is modeled as a sequence of interaction gaps and tunnels, with cavities associated with each gap. The fields are expanded in terms of a sequence of stationary waves anchored on each gap, instead of a set of traveling waves. Space-charge forces are calculated by a fast potential-gradient method instead of from a Green´s function. These methods allow flexibility in the model as well as speed. The method is applied to three simple examples, to show the behavior of components of a TWT, and then to two actual designs.