The Magnetic-Dipole Resonances of Ring Resonators of Very High Permittivity

The lowest magnetic-dipole mode with symmetry of revolution is investigated in a coaxial ring resonator of height L, inner radius b, and outer radius a. Theoretical data are given about the Q of the mode, the eigen magnetic dipole at resonance, and the structure of the fields (electric and magnetic) inside and outside the resonator. The variables are the dielectric constant epsilon_r = N² and the dimensionless ratios b/a and L/2a. The data are valid in the limit of very high epsilon_r. Experiments show them to be already useful at epsilon_r = 35.