Chaotic spectrum of a cavity resonator filled with randomly located sapphire particles.

Abstract

We propose a new approach to the study of correlation properties of electromagnetic waves of a millimeter wave band after multiple passage through a random medium. The approach consists of an investigation of a spectrum of a cavity resonator, filled with randomly located dielectric inhomogeneities. As an object for the approach implementation, the spherical cavity resonator filled with sapphire particles, whose sizes are comparable to a wavelength, was chosen. It is revealed that the spectrum of this resonator in the frequency range 26 GHz-38 GHz is chaotic. A number of correlation effects, such as the effect of "repulsion" of frequencies, the shape of the nearest-neighbor frequency spacing distribution close to the Wigner distribution, the characteristic curve of spectral rigidity, and the correlation of resonance lines on intensity and frequency were found in this spectrum. A superwide frequency band effect of the long retention of an energy of a short microwave impulse in a resonator is exposed and studied. We analyze features of the investigated chaotic spectrum on the basis of the conception of a spatial dispersion of effective dielectric permeability for a medial field in a medium filling the resonator. It is shown that this conception allows us to explain the complete elimination of the degeneration of a spectrum and its chaotization, and also the essential broadening of the resonance lines at the expense of the transfer of energy of dominant transverse modes to strongly damping longitudinal oscillations.