ABSTRACT
This chapter lays down a unified mathematical framework for the design approach to multi-mode resonant antennas. The generalized odd-even mode theory is advanced based on the interior Green’s function expanded in terms of eigenfunctions, to illustrate the symmetry/parity and radiation behavior of resonant antennas under multi-mode resonance. The physical insights of both mode-matching (balanced) and mode-mismatching (unbalanced) effects in antenna systems can be mathematically modeled and quantitatively revealed: Especially, the unbalanced effect can be theoretically explained by the cross-coupled term in the interior Green’s function. Typical resonant elementary antennas, including electric dipole, slot antenna, loop, and rectangular microstrip patch antenna are analyzed, and then used to validate the generalized odd-even mode theory.
