A Numerical Model for Mode Characteristic Analyses of a Rectangular Cavity Loaded With Two Parallel Ladders

A theoretical model and a numerical code were developed for the analyses of the planar ladder circuit. The model treats the circuit as a closed finite length periodic structure with the short boundary in the longitudinal direction. Then, the natural axial modes can be resolved instead of the space-harmonic ones. This enables the mode analysis of the circuit which is very short in length and, on the other hand, the dispersive analysis of the circuit with explicit periodicity of structure. Moreover, such a discrete description of the periodic structure offers additional flexibility in the analysis of a variable pitch circuit. In particular, the effect of the random circuit tolerance in periods on the axial electric field distribution was demonstrated. The formulation is described, and extensive numerical results are presented.