Chaoticity of a Reverberation Chamber Assessed From the Analysis of Modal Distributions Obtained by FEM

Wave chaos theory is used to study a modeled reverberation chamber (RC). The first 200 modes of an RC at a given stirrer position are determined by the finite element method, and the Weyl formula is checked for various RC geometries, from integrable to chaotic. The eigenfrequency spacing distribution varies according to the degree of ray chaos in the RC related to its geometry. The eigenmode distributions are also analyzed and compared to the theoretical Gaussian distribution: close to the lower useable frequency, the modes of the studied chaotic RC fairly respect this asymptotic property. A general result of chaotic systems is illustrated: when perturbed by the stirrer rotation, the resonant frequencies of an RC avoid crossing. This means that the frequency sweeps tend to vanish at high frequency.