3-D Diffusion Models for Predicting Reverberant Electromagnetic Power Density in Loaded Enclosures

Abstract

The power balance technique for the prediction of shielding effectiveness of reverberant enclosures is fast and simple to use. However, it assumes a uniform field in the enclosure, which has been shown to be incorrect in the presence of dissipative contents. The diffusion model is a generalization of the power balance method that can account for the field inhomogeneity due to the presence of losses with much lower computational effort than a full wave solver. Evaluation of a 2D diffusion model produced promising results compared to physical measurements. Here we present a 3D diffusion model applied to an enclosure with an aperture and dissipative contents. Comparisons between the 3D diffusion model, measurements and a full wave solver suggest that it is able to account for the variation of the electromagnetic field due to dissipative contents with far less computational effort than full wave solvers. The diffusion model allows rapid solution of the shielding effectiveness of enclosures with dissipative contents and arbitrary geometries. and reduces the time to model equipment enclosures from hours to minutes, whilst still determining the variation of field strength due to contents. In addition, the method may help predict field inhomogeneity in reverberation chambers.

Efficient Statistical Model for Predicting Electromagnetic Wave Distribution in Coupled Enclosures

“…Such a presumption no longer holds when the loss of the cavity wall becomes so high such that the energy distribution near the system boundaries and from the input to the output aperture drop considerably. In this case, PWB needs to be replaced with other methods such as ray tracing [36] or the DEA analysis [39] or, in the case of multiple scatterers in each cavity, using an approximate flow solver based on a 3D diffusion model [65]; all these methods have a larger computational overhead compared to PWB. Strong damping also violates the random plane wave hypothesis crucial to the RCM [57,62,66].…”

Efficient Statistical Model for Predicting Electromagnetic Wave Distribution in Coupled Enclosures

“…Such a presumption no longer holds when the loss of the cavity wall becomes so high such that the energy distribution near the system boundaries and from the input to the output aperture drop considerably. In this case, PWB needs to be replaced with other methods such as ray tracing [34] or the DEA analysis [37] or, in the case of multiple scatterers in each cavity, using an approximate flow solver based on a 3D diffusion model [60]; all these methods have a larger computational overhead compared to PWB. Strong damping also violates the random plane wave hypothesis crucial to the RCM [54,59,61].…”