Distribution of the Field of Whispering-Gallery Modes in a Radially Nonuniform Two-Layer Cylindrical Dielectric Resonator

We study eigenmodes of a radially nonuniform two-layer cylindrical dielectric resonator bounded by two perfectly conducting planes at its ends. Formulas for the electromagnetic-field components of the modes and the characteristic equation of the resonator made of anisotropic dielectrics and immersed in an anisotropic medium are obtained. Resonators with various whispering-gallery modes are studied numerically in the 8-mm wavelength range. The distributions of the axial field component of the eigenmodes over the radial coordinate are given for various values of the radius, dielectric permittivity, and loss tangent of the inner layer of the resonator. The influence of the inner-layer parameters on the behavior of field distribution over the radius and on the spectral and energy characteristics of the resonator are analyzed.