Optimized ADI-FDTD analysis of circularly polarized microstrip and dielectric resonator antennas

A dispersion-optimized alternating-direction implicit finite-difference time-domain (ADI-FDTD) method is presented in this letter for the accurate modeling of complex electromagnetic structures. The analysis focuses on circularly polarized slot-coupled microstrip and dielectric resonator antennas. Introducing a class of three-dimensional spatial/temporal operators, the novel algorithm yields robust curvilinear grids which efficiently treat fine details and interfaces. Hence, the serious dispersion errors of the usual schemes, as time-steps surpass the Courant limit, are greatly reduced, enabling fast broad-band simulations. Numerical validation confirms the above merits via various realistic structures.