RFID system with configurable RF port

摘要

An active RFID tag has an antenna inside RF-blocking enclosure having a port with a selected shortest dimension. An RFID reader located outside the enclosure at a reader position transmits a downlink RF signal through the port as a directional RF signal on a downlink carrier frequency corresponding to a downlink wavelength smaller than the selected shortest dimension. The port is selectively configured so that the directional downlink RF signal can pass through the port in an access mode during a selected access time interval and are attenuated by at least 60 dB in a restricted mode during a selected restricted time interval that does not overlap with the access time interval.

主权项

1. An RFID system, comprising:
a) an RF-blocking enclosure having a port with a selected shortest dimension, the enclosure configured so that a downlink RF signal of a selected downlink power passing through the port from a selected direction provides a received power at a selected antenna location in the enclosure; b) an active RFID tag including a controller and an interior antenna coupled to the controller and located at the selected antenna location, the tag responsive to a selected RF downlink frequency range, wherein the received power is not less than a receive sensitivity of the active RFID tag; c) an RFID reader located outside the enclosure at a reader position, the RFID reader adapted to transmit the downlink RF signal as a directional RF signal on a downlink carrier frequency corresponding to a downlink wavelength smaller than the selected shortest dimension, the downlink carrier frequency being within the selected RF downlink frequency range; d) a gate adapted to selectively configure the port so that the directional RF signal transmitted by the reader in the selected direction can pass through the port in an access mode during a selected access time interval and is attenuated by at least 60dB in a restricted mode during a selected restricted time interval that does not overlap with the access time interval; e) a controller adapted to automatically control the gate; and f) a non-RFID-active object to which the RFID tag is affixed and a sensor for detecting that the non-RFID-active object is in a selected location, wherein the controller causes the gate to configure the port in the access mode when the sensor detects the object in the location.