Conical beam control of arbitrary conical spiral antennas

The conical beam forming characteristics of a two-arm and a four-arm conical spiral antenna with arbitrary configuration are researched in this paper. The antennas are analyzed based on the Nakano integral equation and the moment method. The results show that their beam direction can be changed by adjusting the winding denseness of the antennas. With the increase of the winding denseness their beam deviation from the axis increases to form conical shaped radiation patterns. The beam deviation of equiangular conical antennas from the axis is wider than that of Archimedean conical antennas. Archimedean conical antennas are better than equiangular conical antennas in beam conformity.