Application of a sub-cell FDTD algorithm for modeling thin radomes covering microstrip patch antennas

The finite difference time domain (FDTD) method is widely used for radiation and scattering problems in electromagnetics. For modeling thin structures, the standard scheme that uses a uniform cell-size grid requires excessive simulation time and memory requirements. One solution to the problem of modeling thin structures is to use a sub-cell FDTD algorithm and use special update equations in the fields in the region of interest. We study the application of the sub-cell method to the modeling of thin radomes covering microstrip arrays in space based applications. The ability to model dielectric radomes that are thin relative to cell-size in FDTD is an important aspect in predicting the accurate resonant frequency in microstrip antennas. Simulation results are compared with existing results in the literature and also with measurement.