Helically counter-poised monopole antenna

Abstract

A novel method of reducing the size of a conventional dipole antenna is introduced by means of replacing one of the dipole arms with a helical element. The result of this asymmetrical arrangement is an antenna that presents an omnidirectional pattern with a modest reduction in gain and bandwidth, in comparison to a symmetrical dipole antenna. The structure is effectively represented as a helically counter-poised monopole. It is shown that the counter-poised helix for the monopole, effectively replaces the ground plane of a conventional monopole antenna, or alternatively by using this method the antennas size can be significantly reduced from a full dipole. The principle is validated through measurement of return loss, antenna gain and cross-polarization level.