US Patent 7474272 Parasitic element for helical antenna

A parasitic element for a helical antenna having at least one helix conductor extending from a secured first longitudinal end of the antenna to an opposite free second longitudinal end thereof around an antenna major-axis. The parasitic element includes an electrically conductive ring located adjacent and spaced apart from the second end in a direction leading away from the first end with the ring axis being parallel to and substantially collinear with the antenna major-axis. The ring has an outer diameter substantially equal to the diameter of the helix conductor at the second end.