Switching patch antenna
AssigneeAlien Technology Corporation
InventorsCurt Carrender, Paul S. Drzaic, Robert Martin, Gregory P. Katterhagen, John M. Price
Life of this patent
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Abstract
According to an embodiment of the invention, a patch antenna includes a patch coupled to a ground plane. The ground plane includes a first and second strip line. When the first strip line is activated, the antenna generates a signal having a first polarization, and when the second strip line is activated, the antenna generates a second polarization. The first polarization may be a horizontal polarization, and the second polarization may be a vertical polarization. The antenna may be incorporated into a radio frequency identification (RFID) interrogator, which may be used to read RFID tags attached to individual items.
Claims17
An antenna comprising:
- a patch element;
- a ground plane coupled to the patch element;
- a first strip line in the ground plane coupled directly to a first edge of the patch element, the first strip line to propagate a first polarized signal in a first direction when activated;
- a second strip line in the ground plane coupled directly to a second edge of the patch element, the second strip line to propagate a second polarized signal in a second direction when activated, wherein the first strip line is activated separately from the second strip line;
- a first impedance matching flare coupled between the first edge of the patch element and the first strip line to adjust characteristics of the antenna;
- and
- a second impedance matching flare coupled between the second edge of the patch element and the second strip line to adjust characteristics of the antenna.
An interrogator comprising:
- a transmitter;
- a receiver coupled to the transmitter;
- a decoder coupled to the receiver to decode received signals;
- and
- an antenna coupled to the receiver and the transmitter, the antenna comprising a patch element coupled to a ground plane, a first strip line in the ground plane to propagate a first polarized signal in a first direction, a second strip line in the ground plane to propagate a second polarized signal in a second direction, wherein the first strip line is activated separately from the second strip line, and
- wherein the first strip line is coupled to a first edge of the patch element and second strip line is coupled to a second edge of the patch element.
A method comprising:
- alternately activating a first strip line on an antenna to propagate a first signal having a first polarization and activating a second strip line on an antenna to propagate a second signal having a second polarization;
- searching for an identification tag using the first and second signals;
- and
- identifying the identification tag,
- wherein the second polarization is oriented greater than zero degrees and less than ninety degrees from the first polarization.
A method comprising:
- alternately activating a first strip line on an antenna to propagate a first signal having a first polarization and activating a second strip line on an antenna to propagate a second signal having a second polarization;
- searching for an identification tag using the first and second signals;
- identifying the identification tag;
- and
- changing a frequency of the first and second signals.
Dependencies are inferred from the claim text.