摘要:
An RFID system has an active tag with one antenna inside, and one outside, an RF-blocking enclosure having a port with a selected shortest dimension. The RFID reader is located outside the enclosure and uses a selected RF read frequency range. The RFID tag simultaneously transmits on a plurality of frequencies corresponding to respective wavelengths smaller than the selected shortest dimension, so that a respective beat frequency is defined between two of the frequencies. The beat frequency is within the selected RF uplink frequency range. The tag transmits a first signal at a first one of the plurality of frequencies using the interior antenna and a second signal at a second, different one of the plurality of frequencies using the exterior antenna.
摘要:
An RFID system includes a reader with antenna, a first barrier, a tag with a link antenna, a second barrier, and two key antennas connected to the tag, mechanically arranged in that order. The first barrier has two or more apertures in it to produce an interference pattern of a security signal from the reader. The security signal interference pattern passes at least partly through the second barrier. One of the key antennas is at a peak of the pattern after passing through the second barrier, and one is not. The tag includes a controller responsive to a downlink signal from the reader to transmit an uplink signal using the link antenna, but only if the downlink signal is preceded by the security signal and the security signal is received more strongly by the key antenna at the peak than by the other key antenna.
摘要:
An RFID system has an active tag with one antenna inside, and one outside, an RF-blocking enclosure having a port with a selected shortest dimension. The RFID reader is located outside the enclosure and uses a selected RF read frequency range. The RFID tag simultaneously transmits on a plurality of frequencies corresponding to respective wavelengths smaller than the selected shortest dimension, so that a respective beat frequency is defined between two of the frequencies. The beat frequency is within the selected RF uplink frequency range. The tag transmits a first signal at a first one of the plurality of frequencies using the interior antenna and a second signal at a second, different one of the plurality of frequencies using the exterior antenna.
摘要:
A classification of a container is identified using a mobile station including an image capture device and an RFID reader having a reader antenna. The container has two RFID tags affixed thereto at respective, different locations. Each tag has a directional antenna steered in a different direction, so that a reader location is defined in the intersection of the antenna propagation patterns. Using the image capture device, one or more images of the container are captured. A controller determines, using the captured image data, whether the mobile station is in a candidate reader location. When the mobile station is in the candidate reader location, the RFID reader attempts to read both tags. If both tags are read while the mobile station is in the candidate reader location, the controller determines the classification of the container is a classification corresponding to the candidate reader location.
摘要:
Non-RFID-active units in a space are marked by affixing RFID tags. Two tags are affixed to each unit, each tag having a directional antenna. The antennas are oriented to define a per-unit reader location. Units are arranged in the space so the per-unit reader locations at least partially overlap to define a reader location. The units in the space can also be detected by an RFID reader located in the overlapping per-unit reader locations. A controller can compare a received list of tag identities corresponding to units expected to be in the container to the identities of the tags read to determine whether the expected units are in the container and disposed at positions and with orientations that cause the respective per-unit reader locations to at least partially overlap with the reader location.
摘要:
RFID tags are read using an RFID reader. A non-RFID-active object has two RFID tags affixed thereto at respective, different tag locations. Each tag has a respective directional antenna steered in a respective, different direction. Respective directional propagation patterns are thus defined and a reader location is defined in the intersection of the propagation patterns. An RFID reader with a reader antenna located at the reader location is provided. The RFID reader is activated to read both tags.
摘要:
An RFID system includes an RF-blocking enclosure having a port with a selected shortest dimension. An active RFID tag including a controller and an interior antenna coupled to the controller is located in the enclosure. The tag responds to a selected RF downlink frequency range. An RFID reader located outside the enclosure simultaneously transmits directional RF signals on a plurality of frequencies corresponding to respective wavelengths smaller than the selected shortest dimension, the plurality including a carrier frequency and an interference frequency. A beat frequency is thus defined between the carrier frequency and the interference frequency and the beat frequency is within the selected RF downlink frequency range, so that the transmitted signals pass through the port and the tag responds to the beat frequency.
摘要:
A classification of a container is identified using a mobile station including an image capture device and an RFID reader having a reader antenna. The container has two RFID tags affixed thereto at respective, different locations. Each tag has a directional antenna steered in a different direction, so that a reader location is defined in the intersection of the antenna propagation patterns. Using the image capture device, one or more images of the container are captured. A controller determines, using the captured image data, whether the mobile station is in a candidate reader location. When the mobile station is in the candidate reader location, the RFID reader attempts to read both tags. If both tags are read while the mobile station is in the candidate reader location, the controller determines the classification of the container is a classification corresponding to the candidate reader location.
摘要:
An RFID system includes a reader with antenna, a first barrier, a tag with a link antenna, a second barrier, and two key antennas connected to the tag, mechanically arranged in that order. The first barrier has two or more apertures in it to produce an interference pattern of a security signal from the reader. The security signal interference pattern passes at least partly through the second barrier. One of the key antennas is at a peak of the pattern after passing through the second barrier, and one is not. The tag includes a controller responsive to a downlink signal from the reader to transmit an uplink signal using the link antenna, but only if the downlink signal is preceded by the security signal and the security signal is received more strongly by the key antenna at the peak than by the other key antenna.
摘要:
An RFID system includes an RF-blocking enclosure having a port with a selected shortest dimension. An active RFID tag including a controller and an interior antenna coupled to the controller is located in the enclosure. The tag responds to a selected RF downlink frequency range. An RFID reader located outside the enclosure simultaneously transmits directional RF signals on a plurality of frequencies corresponding to respective wavelengths smaller than the selected shortest dimension, the plurality including a carrier frequency and an interference frequency. A beat frequency is thus defined between the carrier frequency and the interference frequency and the beat frequency is within the selected RF downlink frequency range, so that the transmitted signals pass through the port and the tag responds to the beat frequency.