The circular polarized antenna printed on the rectangular dielectric substrate is proposed and numerically analyzed. The end of center conductor of coplanar waveguide is extended so that the shape of antenna becomes rectangle. At the design frequency of 2.45GHz. The S11 becomes -23.27dB and the axial ratio is 2.46dB. In the numerical analysis, the electromagnetic Simulator “WIPL-D” based on the Method of Moment is used.