Antenna-less RFID Tags Enable Use on Metal and Liquid-Filled Containers (RFT-375)

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Invention Summary


RFID (Radio Frequency Identification) tags have become a standard way to track items by both the government and industry. A typical RFID tag is made up of an integrated circuit (IC) and an antenna.  While there are many types of RFID tags available, most will not work well on metal objects or containers filled with liquid.

Previous attempts to solve this problem and create tags that work with metal or liquid containers have led to bulky RFID tags (up to 3 cm in thickness) that are easily destroyed by handling during typical use.  An NDSU researcher has developed a novel approach to this problem involving an antenna-less RFID tag, which works well in these problem situations while allowing for an inexpensive and manufacturable product tracking solution.


  • RFID tag design performs well on metal and liquid-filled objects.
  • Novel design approach eliminates the need for mechanical stand-offs and bulky packaging.
  • Significantly reduced production cost over existing on-metal RFID solutions.
  • Believed to be compatible with roll-to-roll manufacturing processes with optimization.

Invention Premise

The invention is a low-profile, high-permeability antenna-less RFID tag for use on large metal objects and other objects for which traditional RFID technologies will not work. The approach, illustrated in Figure 1, is to incorporate high-permeability materials in the tag to create an impedance across a metal surface, such as a metal container, diverting current into the tag’s integrated circuit (IC).  This type of tag is essentially ‘antenna-less’ as it uses the ground plane (the metal surface on which it is mounted) to excite currents through the IC. Tags using high-permeability materials in this manner are significantly thinner than those developed using other methods.


This technology is patent pending and immediately available for licensing/partnering opportunities.