Alternative surface integral equation-based characteristic mode analysis of dielectric resonator antennas

摘要

Dielectric resonator antennas are widely used in wireless communication systems. A theory of characteristic modes (CMs) for modal analysis of dielectric resonators is highly demanded. Although a few earlier studies had proposed CM theory for modelling scattering from dielectric bodies, the physical characteristics of these CMs and their eigenvalues are not as clear as that of those for conducting bodies. This study revisits the CM theory for dielectric resonators. Following the Poynting's theorem and the PMCHWT (Poggio, Miller, Chang, Harrington, Wu, and Tsai) equation, two generalised eigenvalue equations are formulated. The resultant eigenvalues possess clear physical meanings that are the same as those of perfectly electrically conducting problems. In addition, other possible CM formulations based on the PMCHWT equation are also discussed. Mathematical proofs are given in the Appendix to show how to formulate CM theory to physically describe the fundamental resonant modes of dielectric resonators. Numerical results are given to show the proposed CM formulations are effective in solving resonant frequencies and modal fields for dielectric resonators.