System for detecting radio-frequency identification tags
First Claim
1. A system, comprising:
- a plurality of radio frequency (RF) antennas set up to provide one or more interrogation corridors; and
a RF reader coupled to the plurality of antennas, the RF reader having a transmitter/receiver (T/R) port that provides each of the antennas with RF power to produce interrogation fields within the interrogation corridors.
1 Assignment
0 Petitions
Accused Products
Abstract
Techniques for detecting radio-frequency identification (RFID) tags are disclosed. For example, an exit control system is described that detects unauthorized removal of articles from a protected facility. A series of antennas are setup to produce interrogation corridors located near the exit of the protected area. RFID tags are attached to the articles to be protected. Each tag includes information that uniquely identifies the article to which it is affixed and status information as to whether the articles removal from the facility is authorized. The RF reader outputs RF signals through the antennas to create electromagnetic fields within the interrogation corridors. The reader outputs RF power from a single port to the multiple antennas via a splitter/combiner. In this way, a single RF reader with only one transmitter/receiver port simultaneously interrogates multiple antennas. A variety of techniques are described by which the reader can detect the removal of an unauthorized article.
44 Citations
27 Claims
-
1. A system, comprising:
-
a plurality of radio frequency (RF) antennas set up to provide one or more interrogation corridors; and
a RF reader coupled to the plurality of antennas, the RF reader having a transmitter/receiver (T/R) port that provides each of the antennas with RF power to produce interrogation fields within the interrogation corridors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A method, comprising:
-
producing a radio frequency (RF) output signal from a single transmitter/receiver (T/R) port of an RF reader;
splitting the RF output signal into a plurality of antenna drive signals; and
delivering the antenna drive signals to a plurality of antennas to produce interrogation fields within one or more interrogation corridors. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
-
-
25. An exit control system for detecting unauthorized removal of articles from a protected area, the exit control system comprising:
-
a plurality of antennas oriented to provide interrogation corridors; and
an RF reader that provides RF power to the antennas to produce interrogation fields in the interrogation corridors, wherein the RF reader interrogates the plurality of antennas using a single port to transmit RF power to the antennas and to receive tag signals from the antennas at the single port.
-
-
26. A computer-readable medium comprising instructions that cause a processor to:
-
receive from a single reader a tag detection signal that indicates at least one tag is present within any of a plurality of interrogation corridors;
receive a patron signal that indicates at least one patron is present within any of the interrogation corridors; and
output an alarm signal upon receiving the tag detection signal and the patron signal within a time period. - View Dependent Claims (27)
-
Specification