Improvement of Probe Feeding Simulation in FDTD by using Probe Current Compensation Method and Overlapping- grid Technique

Abstract

In the field of wireless-communication, the exact analysis for ANT/RF/MW(Antenna/Radio Frequency/Microwave) structure has been required.

There are a lot of numerical analysis methods such as MOM(Moment Of Method), FEM(Finite Element Method), FDTD(Finite Difference Time Domain) for the analysis of ANT/RF/MW structure. However, most of numerical analysis methods are based on frequency domain. The analysis should be performed for all frequencies in the operation bands. On the other hand, the electromagnetic scattering characteristics can be analyzed in the time and spatial domain simultaneously via a FDTD method.

In addition, FDTD is used widely since it can be applied efficiently according the shape of the analyzed structure. However, in the conventional FDTD program, analysis of the electromagnetic structure is based on rectangular cells, therefore it has lack of accuracy in the analysis of spherical & cylindrical structures. Therefore, in order to analyze spherical & cylindrical structure, the lack of accuracy in FDTD method should be compensated.

In this thesis, PCC(Probe Current Compensation) & OGM(Overlapping-Grid Method) were methods employed to compensate for the inaccuracy of conventional FDTD method. In the OGM the cylindrical & rectangular coordinates are used simultaneously to analyze the mixed structure with rectangular & cylindrical structures. PCC was also employed to make up for the inaccuracy in the calculation of probe current. According to the experiment and theoretical results, the methods proposed in this thesis showed a good agreement with conventional RF-CAD(Radio Frequency Computer Aided Design), which indicates that these methods are promising candidates for the analysis of ANT/RF/MW.