Miniaturization of patch antenna based on hybrid topology optimization

Abstract

A hybrid topology optimization method that combines the scalar isotropic material with penalization and the level set method is utilized to achieve the miniaturization of patch antennas while maintaining good radiation and polarization characteristics. In order to achieve this goal, the Heaviside projection filter is applied to obtain topologies that are more complex. Both the radiation power and the reflection coefficient of the antenna are utilized as sub-objectives. Besides, by setting the radiation patch to be symmetrical, not only the numbers of optimization variables and optimization sub-objectives are reduced, but also the cross-polarization level is suppressed effectively, so that the optimization is accelerated. The optimized patch antenna achieves good performance in patch size, impedance matching, radiation pattern, gain, and polarization characteristics. Compared with the reference patch antenna, the patch size of the optimized antenna is reduced by 63%, while the maximum realized gain and efficiency remain basically unchanged, achieving more than 5.9 dBi and 90%, respectively. Due to its very small size patch, the antenna is particularly suitable for compact multi-antenna and antenna array applications.