Optimization of circular polarized patch antenna with cross-shaped slit

摘要

The GPS (Global Positioning System) has come into wide use in Japan. A high performance and low cost, small GPS antenna is required. In this paper, a small circular polarized patch antenna for GPS satellite receivers is investigated. Patch antenna miniaturization can be achieved by adding a slit or slot on the patch element of the antenna. The current path on the patch element increases, and resonant frequency drops by adding the slit. We first investigate the case of a square patch antenna with 4 slits from both sides of the patch. By changing the parameter of the slit structure, an optimum slit parameter for antenna miniaturization is proposed. Then, in order to achieve more miniaturization, a patch antenna with cross-shaped slit is simulated. Parameter optimization is carried out. Finally, the antenna axial ratio is investigated, and an optimum small circular polarized antenna is proposed. A high performance three-dimensional FDTD algorithm using a nonuniform mesh that allows flexible cell size to improve the accuracy of modeling and reduce the computational resources is adopted in this study.