Patent ID: 8044874

Claim:
A planar antenna apparatus comprising: a planar, electrically conductive, patch antenna element having a geometric shape defining an outer perimeter and being devoid of a ground plane adjacent thereto; and a pair of spaced apart signal feedpoints along the outer perimeter of the planar, electrically conductive, patch antenna element and separated by a distance of one quarter of the outer perimeter and configured to impart a traveling wave current distribution; each of the signal feedpoints defining a discontinuity and comprising a notch extending inwardly from the outer perimeter toward a center of the planar, electrically conductive, patch antenna element; the outer perimeter of the planar, electrically conductive, patch antenna element being equal to about one operating wavelength thereof; a feed structure coupled to the signal feedpoints to drive the planar, electrically conductive, patch antenna element with a phase input to provide at least one of linear, circular, dual linear and dual circular polarizations.