Three-dimensional FE modeling of multistage depressed TWT collectors

In this paper a fully three-dimensional (3-D) finite element (FE) approach for the electromagnetic analysis of multistage depressed travelling wave tube (TWT) collectors is presented. In the model a coupled stationary electromechanical problem is iteratively solved; convergence to solution is obtained by using a congruent representation of the unknown 3-D spatial charge density. A FE computer code, based on the above iterative scheme, has been developed and used to carry out several 3-D analyses of TWT collectors.