Stacked dipole antenna for use in wireless communications systems

摘要

A dipole antenna for use with a mobile subscriber unit in a wireless communications system. The antenna is fabricated with printed circuit board (PCB) photo-etching techniques for precise control of the printed structure to mass produce antenna elements with repeatable features. The antenna includes a planar substrate made of dielectric material. A conductive planar element layered on one side of the substrate, and a conductive planar ground patch is located on the other side of the substrate. The conductive planar element is located in an upper region of the substrate, while the location of the planar ground patch is offset from the conductive planar element in a lower region of the substrate. A feed strip is connected to the conductive planar element, extends from the element to a bottom edge of the substrate, and terminates at a bottom feed point. The conductive planar ground patch includes two portions. One portion extends from the midsection of the other portion to the bottom edge of the substrate and provides a connection point for coupling the conductive planar ground patch to a ground plane which is aligned orthonormally to the substrate. Capacitive coupling between the conductive planar element and the conductive planar ground patch creates a junction which provides an upper dipole feed point in a mid-region of the substrate such that the conductive planar element acts as a first element of an unbalanced dipole antenna and the conductive planar ground patch acts as a second element of the unbalanced dipole antenna. The unbalanced dipole antenna forms a beam which may be positionally directed along a horizon that is substantially parallel to the ground plane.