An Ultrawideband Dipole With a Director as a Feed for Reflector Antennas

A novel ultrawideband directional flat dipole capped by a planar director is proposed in this letter. The novelty of the antenna is the great improvement of the bandwidth of a flat dipole above an ordinary finite ground plane by using a simple parasitic top patch, referred to as the "director." A linearly polarized prototype has been designed and manufactured, and achieved a nearly 3:1 operating bandwidth (2.2-6.5 GHz) with a return loss higher than 10 dB, nearly constant radiation patterns, and high aperture efficiency over the entire operating band.