Natural oscillations of radially three-layered dielectric resonators

Natural oscillations of radially three-layered dielectric resonators have been investigated. The latter have the form of a sphere and cylinder limited by ideally conducting end planes. The expressions for components of electromagnetic fields of natural oscillations and characteristic equations of resonators were obtained. Numerical investigations of resonators were carried out in the 8-millimeter wavelength band. The impact of the middle layer parameters of resonators on their spectral and power characteristics was also analyzed. It was proposed to use such resonators for extracting the complex dielectric permittivity of substances