Generalized system function analysis of exterior and interior resonances of antenna and scattering problems

The generalized system function H(s), directly associated with radiated and scattered fields, is presented to effectively analyze the exterior and interior resonances of antenna and scattering systems in this paper. H(s) is constructed by using the model-based parameter estimation technique combined with the complex frequency theory. The behaviors of the exterior and interior resonances can be distinguished by analyzing the characteristics of pole-zero of H(s) in a finite operational frequency band. The intensity of the exterior resonance can be effectively estimated in terms of Q values and residues at the complex resonant frequencies. The truly scattered fields from a closed conducting region can be obtained by eliminating the poles corresponding to the interior resonances from H(s). Some examples of the practical antenna arrays and scattering systems are given to illustrate the application and validity of the proposed approach in this paper.