The Method for the Fields Distribution Description in Periodical Structures

The variational method for numerical simulation of rf parameters of periodical structures with arbitrary phase shift per structure period is developed. At any phase shift the field distribution is represented as a sum over trial functions. As trial functions we use numerically simulated field distribution, considering with different boundary conditions only one structure period. By using standard variational technique and Floquet boundary conditions, the generalized symmetrical eigen-value problem is formed. Due to successful choice of trial functions, which keep a lot of information about the real structure shape, the method has fast convergence. Not so many trial functions are needed to describe good the field distribution. The method combines the powerful ideas of variational approach with possibilities of modern computer codes for direct simulations. A lot of applications, both for structure parameters calculations and for general properties investigation, are possible.