Physical considerations on complex cavities in undermoded regime

In this paper, a theoretical investigation about undermoded mode-stirred reverberation chambers is presented and discussed. This is based on the assumption of a sinc-correlated vector plane-wave angular spectrum. We extend the plane wave superposition to include such correlated scenario and find an integral representation for the total field coherency (single point correlation). This clearly exhibits spatial inhomogeneity and agrees with both Sommerfeld´s far-field radiation condition and Berry´s conjecture for chaotic scattering in confined wave systems. Finally, we find a closed-form solution for the coherency at the center of the reference frame, serving as a normalization factor to compare with measurements in complex inhomogeneous environments. Several physical considerations arise from this novel analytic representation.