RFID reader with automatic near/far field interrogation mode switching, and related operating methods
A dual-mode RFID reader is capable of automatically switching from a far-field interrogation mode to a near-field interrogation mode upon the detection of certain operating or handling conditions. The RFID reader includes an RFID radio module configured to support a far-field interrogation mode and a near-field interrogation mode, an antenna arrangement coupled to the RFID radio module, and a mode-switch sensor architecture coupled to the RFID radio module. The mode-switch sensor architecture is configured to detect conditions indicative of near-field interrogation, and the RFID radio module automatically configures itself for operation in the near-field interrogation mode upon detection of such conditions.
1. A method of operating a mobile RFID reader that operates in a far-field mode for concurrently interrogating a plurality of RFID tags and in a near-field mode for individually interrogating one RFID tag at a time, the method comprising:
capturing image data, with an optical sensor, of an object within an interrogation field of the mobile RFID reader;
processing the image data to detect whether the object is out of focus;
determining that the object is within close proximity to the mobile RFID reader when the image data indicates that the object is out of focus;
automatically configuring the mobile RFID reader for operation in the near-field mode when the image data indicates that the object is out of focus; and
thereafter, interrogating an RFID tag while the mobile RFID reader is in the near-field mode.
2. The method of claim 1 , further comprising automatically configuring the mobile RFID reader for operation in the far-field mode after successfully interrogating the RFID tag.
3. A dual-mode RFID reader comprising:
an RFID radio module configured to support a far-field interrogation mode and a near-field interrogation mode;
an antenna arrangement coupled to the RFID radio module and configured to support the far-field interrogation mode and the near-field interrogation mode; and
a mode-switch sensor architecture coupled to the RFID radio module and configured to detect conditions indicative of near-field interrogation; wherein:
the RFID radio module automatically configures itself for operation in the near-field interrogation mode upon detection of the conditions;
the mode-switch sensor architecture comprises an optical sensor configured to capture image data of an object within an interrogation field of the dual-mode RFID reader, and comprises an image processor that analyzes the image data; and
the RFID radio module automatically configures itself for operation in the near-field interrogation mode when the image processor detects that the object is out of focus and within close proximity to the dual-mode RFID reader.