A simple cross shaped loop antenna radiating circularly polarization waves by one port feeding

An electrically small circularly polarized loop antenna is presented. The authors have shown that a cross shaped loop antenna, CSA, can radiate circular polarization waves even if it has a single port. In this paper, the CSA that we succeed in downsizing as keeping its performance of circular polarization is proposed. Moreover, it has been verified that winding a loop element as a cross shape help to tune the antenna´s input impedance into 50 ohms, as well as, to reduce the unbalance current flowing from a coaxial cable. The structure of the antenna is simple enough to be produced in commercial quantities. Moreover, the radiation gain and axial ratio of circular polarization are good enough as a built-in antenna.