Alternative Characteristic Mode Solvers for Metallic-Dielectric Composite Structures

Characteristic mode (CM) theory has become a valuable tool in the design of antennas and analysis of scattering. Well-content CM solvers that are immune to spurious modes and efficient for frequency sweeping are still in need, especially for composite structures containing lossy material. In this letter, an alternative procedure for CM extraction of arbitrarily combined metallic-dielectric bodies is presented based on using the surface integral equations. The spurious modes are suppressed through the elimination of dependent unknowns, and the efficiency is raised by using a single effective current instead of both the equivalent electric and magnetic currents in the conventional methods. Numerical results are provided to demonstrate the viability of the proposed approach.