Directional antenna for RFID tag finder
First Claim
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1. A method comprising:
- activating a first antenna;
determining, by the first antenna, a general presence of a transponder in an area based on a signal received at the first antenna from the transponder;
while the first antenna is activated, activating a second antenna designed to have a null or minimum in a first direction and a radiation pattern in all directions other than the first direction so that first signals transmitted by the first antenna indicate a transponder is within an area while second signals of the second antenna indicate a direction of the transponder in the area;
while the first antenna determines that the transponder is in the area, identifying, by the second antenna, a direction the null or minimum is directed toward when a lack of response to the second antenna occurs; and
determining, by a processor, a location of the transponder within the area based on (1) the first antenna determining that the transponder is in the area, (2) the direction the null is directed toward when the lack of response is received by the second antenna, and (3) multiple reads of the transponder within the radiation pattern.
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Abstract
A system may include a mobile device comprising an antenna system. The antenna system may include a first antenna to determine a presence of a transponder within an area and a second antenna comprising a directional radiation pattern and that is configured to sweep the area to determine a direction of the transponder. The first antenna may be separate from the second antenna.
11 Citations
19 Claims
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1. A method comprising:
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activating a first antenna; determining, by the first antenna, a general presence of a transponder in an area based on a signal received at the first antenna from the transponder; while the first antenna is activated, activating a second antenna designed to have a null or minimum in a first direction and a radiation pattern in all directions other than the first direction so that first signals transmitted by the first antenna indicate a transponder is within an area while second signals of the second antenna indicate a direction of the transponder in the area; while the first antenna determines that the transponder is in the area, identifying, by the second antenna, a direction the null or minimum is directed toward when a lack of response to the second antenna occurs; and determining, by a processor, a location of the transponder within the area based on (1) the first antenna determining that the transponder is in the area, (2) the direction the null is directed toward when the lack of response is received by the second antenna, and (3) multiple reads of the transponder within the radiation pattern. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus comprising:
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a first antenna to determine a presence of a transponder within an area; and a second antenna that is activated in combination with a first antenna, wherein the second antenna comprising a directional radiation pattern is configured to sweep the area to determine a direction of the transponder while the first antenna determines the presence of the transponder is within the area, wherein the first antenna is separate from the second antenna, and wherein the second antenna is configured to generate a radiation pattern that includes a null in a first direction; a third antenna that is perpendicular to the second antenna and which sweeps about an axis that is perpendicular to a sweeping axis of the second antenna; and a processor that determines a location of the transponder within the area based on (1) the first antenna determining that the transponder is in the area, (2) the direction the null is directed toward when a lack of response is received by the second antenna, and (3) multiple reads of the transponder within the radiation pattern. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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16. A system comprising:
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a RFID reader comprising a nulling antenna; wherein the nulling antenna outputs a null or minimum extending only in one direction so that when the null is directed toward a transponder, the RFID reader is prevented from receiving signals from the transponder, and wherein, while an omnidirectional antenna determines that the transponder is in an area, the nulling antenna continuously sweeps about an axis to determine;
(1) a presence based on receipt of the signal when a maximum of the omnidirectional antenna is directed toward the transponder in the area and (2) a direction of the nulling antenna when a lack of signal from the transponder is received, wherein a first signal transmitted by the omnidirectional antenna is maximized and a nulling signal transmitted by the nulling antenna is minimized at the same time; andwherein a processor determines a location of the transponder based on (1) the nulling antenna determining that the transponder is present in proximity of the nulling antenna, and (2) the direction the null is directed toward when a lack of response is received by the nulling antenna, and (3) multiple reads of the transponder within the area. - View Dependent Claims (17, 18, 19)
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Specification