On Transient Electromagnetic Excitation of a Rectangular Cavity Through an Aperture.

摘要

Induction theorem is used to formulate the problem of transient electromagnetic excitation of a rectangular cavity through an aperture. New variables are introduced to convert the governing second-order differential equation into a set of first-order equations which correspond to normalized state equations. This conversion will result in faster convergence in the numerical solution. Moment method is employed to solve the equations subject to specified boundary conditions. Cavity fields are expressed in terms of subsectional expansion functions with time-dependent coefficients, and external fields are represented as superpositions of plane waves. These fields are properly matched at the aperture. The procedure for evaluating a typical expansion-coefficient vector by singularity-expansion method is outlined. The formulation takes into account the effect of reflections from cavity walls on the aperture field and does not require that the aperture be small. (Author)