UHF RFID Kernel Tagging
Publication Date: 2009-Apr-13
The IP.com Prior Art Database
UHF RFID Kernel Tagging of Metal Signs and Similar Thin Metal Objects
Problem Solved by the Present Invention:
Traditional RFID labels will not work directly on the metal surface of a traffic or street sign. Encapsulated and offset tags are expensive and can only be read from one side of the sign. Durability is also a concern with this type of use.
The present invention allows for an RFID tag to be read at distances greater than 5 meters from either side of a metal sign with a single tag. The tag could either be a durable printed label or a `snap-in' plastic enclosure.
In addition to the asset tracking benefit, the tags could also be used to enable "smart signs". If vehicles using the road were equipped with RFID readers, the tags on the signs could be used to transmit information to the driver, e.g. "the speed limit here is 55mph", "Slow Down, School Zone", etc. It could also be useful for emergency vehicles and to augment GPS mapping software.
Beyond street signs, the invention will work on any thin metal object such as vehicle license plates, metal filing cabinets, computer cases, etc.
The adaptive kernel is an RFID tag technology that allows for separation of a UHF tag into two parts: a small loop (approximately lcm by lcm) that includes the chip (kernel), and a larger far-field antenna element. The kernel by itself can only be read at a range of a few centimeters, but when brought within a few millimeters of the far-field element, the two structures couple and the read range increases substantially. Typically, the kernel is coupled to a conductive element such as a dipole or loop.
In the present invention, the kernel...