An Analysis of Reliable FDTD using OGT and Effective Permittivity Boundary Solution for Yee´s Cell Structures

This paper describes reliability of the proposed FDTD method with overlapping-grid technique (OGT) and effective permittivity dielectric boundary solution. In order to solve contour path error at interface of two dielectric media, effective permittivity (EP) approach is calculated and evaluated by the numerical reflection coefficient. Especially, the OGT is applied for simulation of microstrip antenna with a probe feeding structure. In order to confirm the accuracy of EM structure modeling calculated by the OGT, a typical microstrip broadband patch antenna is considered and analyzed. The calculated results are compared with measurement as well as the calculated results of commercial tool. They show a good agreement with the measurement data and the theoretical prediction using commercial tool. To realize the high accuracy of the FDTD approach, it is also considered effective permittivity analysis to reduce reflection error occurred at the boundary of two different dielectric materials in a Yee´s cell structure. The proposed EP solutions are theoretically investigated and compared with the conventional EP solutions (Dey, 1999) calculated an average weighted volumes of corresponding to dielectric permittivity. The numerical analysis performed for several examples is confirmed the reasonable agreement between the theoretical results and numerical calculations.