Electromagnetic field analysis of shielded composite dielectric spherical shell resonator in infrared and visible regions

In this paper, we have presented an electromagnetic field analysis of shielded composite dielectric spherical shell resonator. The resonator studied in this work is considered for the first time as no study on such resonators is available in the published literature to the best of the author's information. This shielded composite dielectric spherical shell resonator is composed of two concentric metal spheres with different dielectric material has been made. The whole assembly is shielded by a perfectly conducting concentric spherical metal. The expression for the resonant frequencies and quality factors have been calculated using numerical methods for both the TEnml and TMnml modes for an infrared and visible regions. It is found that as the outer radius of the shielded composite dielectric spherical shell resonator increases, the quality factor Q of the resonator increases monotonically. It is also found that if we change the radius of the inner dielectric sphere, there is no appreciable change in resonant frequency of the concerned mode is observed. This is due to the small difference in the permittivities of the materials of the inner and the outer dielectric spheres. It has also been observed that an inner concentric superconducting sphere within a dielectric spherical resonator is a more effective controlling parameter of the resonant frequency than the other parameters. (C) 2018 Elsevier Ltd. All rights reserved.