Single feed circularly polarized microstrip antenna and array

In an attempt to obtain circular polarization using a single feed patch antenna, this paper introduces a novel design that consists of two circular patches to cover 5.2 GHz band operation. The big circle is the main patch, and it is merged with a smaller circle at a distance from the center of the main patch for creating both sense of polarization (RHCP, LFHCP). There are advantages of the proposed design such as simplicity to design the antenna at any desired frequency, and transmission lines feeding that reduce the complexity of probe feeding. Sequential rotation of radiating patches with suitable excitation phase shifting has also been applied in this to improve the polarization purity over the wide range of frequencies with higher gain compared to a single patch.