Spectral properties of microwave cavity (billiard) resonator with side surface irregularities

The frequency spectrum of a microwave cylinder resonators with fractures or inhomogeneities of side surface have been studied theoretically, numerically and experimentally. Such resonators can be considered as a microwave system which contains diffusing and focusing portions and it may cause signs of wave chaos in the frequency resonator spectrum. Using the spectral approach we found the signs of wave chaos in the properties of the probability of the inter-frequency intervals distribution. When the cylinder resonator has regular side surface the spectral lines of the resonator are independent, and the probability of the inter-frequency intervals distribution similar to a Poisson distribution. In the case of existence of surface fractures or inhomogeneities, the spectral lines are correlated and the probability of the inter-frequency intervals distribution tends to the Wigner distribution.