A simple circular polarized loop antenna

A novel structure for a circular polarized spiral antenna is presented. The spiral antenna radiates circular polarized waves with only one port even though the structure is very simple. The antenna is designed based on the cross shaped loop antenna, CSA, which is invented by the author. The CSA has begun to radiate circular polarization, by changing some length of the antenna elements. In this paper, the structure of the antenna that has tuned into GPS band is delineated. The return-loss characteristics and radiation pattern of the prototype antenna show that the antenna radiates good circularly polarized waves with 3dB or less axial ratios.