The low-profile hemispherical helical antenna with circular polarization radiation over a wide angular range

The low-profile hemispherical helical antenna is studied experimentally and theoretically. This antenna can produce circular polarization radiation over a wide angular range of 90/spl deg/. The current distribution, the input impedance, the axial ratio, the power gain, and the radiation pattern are rigorously studied. The 3-dB axial ratio bandwidth of a five-turn hemispherical helical antenna is found to be 14.6. In the range of 1.0/spl les/C//spl lambda//spl les/1.3, a relatively stable power gain of more than 9 dB is obtained. The radiation patterns typically consist of a large smooth main lobe with almost no sidelobes. These new antenna characteristics have a potential application in mobile satellite communications.