title: 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.
authors.affiliation: Institute for Radiophysics and Electronics of Ukrainian NAS, 12 Proskura Street, 61085 Kharkov, Ukraine. ganap@ire.kharkov.ua
authors.forename: E M
authors.initials: EM
authors.lastname: Ganapolski
authors.forename: Z E
authors.initials: ZE
authors.lastname: Eremenko