R－FDTD Method With Subgridding And Its Application To The Analyses Of Microstrip Antenna

In this paper, a novel approach of reduced finite-difference time-domain method (R-FDTD) combined with subgridding technique is proposed and applied to the analysis of microstrip-fed slot antennas. Firstly, the impedance and radiation characteristic of a microstrip-fed rectangular-slot antenna are analyzed and the obtained numerical results accord with those in literatures. Compared to normal FDTD method and R-FDTD method, memory requirement and CPU time are reduced obviously by the presented approach. Further more, the input impedance and radiation pattern of microstrip-fed dumbbell-slot antennas and microstrip-fed swallow-tailed-slot antennas in different size are calculated. Both reflectance and pattern of Sierpinski carpet fractal patched antennas have been simulated, too. Some useful conclusions are deduced for the engineering design, which show the relationship between the slot size and antenna bandwidth and the effect of the fractal structure on scattering parameters of patched antennas. Numerical results show that it is feasible and numerically efficient to solve the electromagnetic problem of complex objects incorporating small features by the proposed approach.