RADIATION CHARACTERISTIC ANALYSIS OF S-BAND SPIRAL ANTENNAS MOUNTED ON A SATELLITE BY FDTD SUBGRIDDING ALGORITHM

Abstract

In this thesis, a novel three dimensional FDTD subgridding technique based on the interpolation of the electric and magnetic current densities and sub-grid magic location method is presented. This three dimensional sub-grid method is applied to analyze the composite radiation patterns of the two S band spiral antennas located on a satellite. The two rectangular spiral antennas which are mounted on the satellite are also presented. First, an overview of the formulation and implementation of the FDTD method is presented. Since a satellite is composed of many parts having different sizes and complexity, accurate and efficient sub-gridding FDTD algorithms are also reviewed. After that, a novel three dimensional FDTD method with random odd grid ratio is introduced. Compared to the conventional subgridding method, the proposed scheme utilizes arbitrary odd number mesh grid ratio and reduced calculation time. Both the simulated and measured radiation patterns of S band spiral antennas mounted on a satellite are presented. To verify the accuracy and validity of the proposed three dimensional FDTD scheme, composite radiation patterns of two dipole antennas mounted on a rectangular PEC body are evaluated and the result is compared with that of HFSS.