Direct and inverse resonance problems for shielded composite objects treated by means of the null-field method

Resonances of a composite object shielded by a perfect conductor are investigated using the null-field method. Computed resonance frequencies and quality factors of shielded homogeneous and composite resonators are reported and compared with previously published results whenever possible. conversely, the permittivities and geometric parameters of shielded composite objects are computed from calculated or measured complex frequencies. Good convergence and reasonable agreement with other computed and measured results are achieved for both direct and inverse resonance problems