Transmission cross section for apertures and arrays calculated using time-domain simulations

Continuing advancements regarding computer technology and simulation software means that the shielding performance of increasingly complex apertures can be calculated numerically. Having access to analytical equations that can be used to reduce the computational burden is, however, still desirable. Transmission cross sections are presented for a number of geometrically simple apertures and arrays in perfectly conducting, and infinitely thin, ground planes when illuminated by a plane wave incident from the normal direction. Comparisons are made between results obtained from numerical simulations, analytical equations as well as semi-analytical calculations obtained by combining analytical equations with numerical results. A previously reported transmission line model is shown to provide results in very good agreement with numerical simulations even for apertures with a relatively small value of the length-to-width ratio. For linear arrays of slot apertures excellent agreement is obtained between purely analytical results and numerical results. The final part of the paper presents a benchmark study illustrating the convergence of two different time-domain simulation software. It is also illustrated how the accuracy of the numerical results can be improved by taking into account the discretization of the computational domain.