US Patent 7333059 Compact circularly-polarized patch antenna

An antenna for receiving and/or transmitting circularly polarized RF signals includes a patch element, a ground plane, a dielectric, and a feed line. The patch element is disposed on a pane of glass and includes a pair of radiating sides disposed opposite each other and a pair of spacer sides disposed opposite each other. The radiating sides form an angle less than 90 degrees with the spacer sides. A first axis is defined through a center of the radiating sides and a second axis defined though a center of the spacer sides. The ground plane is disposed substantially parallel to and spaced from the patch element. The dielectric substrate is sandwiched between the patch element and the ground plane. The feed line is disposed substantially parallel to and offset from the first axis for providing the antenna with a circular polarization radiation characteristic. The antenna is compact in size and generally conformal to the pane of glass.