Excitation of Electromagnetic Field Inside Rotating Spherical Cavity

Abstract

Rotating cavities are often used for rotation rate measurement. However, the representation of electromagnetic fields in rotating reference frames is based on simplifying assumptions and approximate solutions. In this article, problem of excitation of electromagnetic field inside a rotating spherical cavity resonator with arbitrary sources of currents and charges is formulated and solved rigorously. The solution is based on the covariant Maxwell's equations. Expressions for the electromagnetic field components are derived using electric and magnetic Debye potentials. Impedance boundary problem of electromagnetic field excitation in a rotating dielectric filled spherical cavity with finite conductivity metal walls is formulated and solved rigorously. In a special case of excitation of the cavity resonator with an elementary electric dipole, the frequency response and the quality factor of the resonator were calculated for different dielectric fillings and metals of the cavity walls. The obtained analytical solutions were verified for the special case of zero rotation rate compared with the simulation of the problem in CAD.