Guidelines for metal environments

The reader creates a magnetic RF field to transfer energy to a passive RFID card and enables bidirectional data communication. Electrically conductive material interferes with this RF field up to total shielding. To avoid this interference, please stick to the following guidelines.

  • "Metal" here is used for any electrically conductive material including e.g. carbon composites
  • "Card" here includes key fobs and other non-card-shaped transponders
  1. Avoid metal between reader and card.
    Coins and other metal parts significantly smaller than the card antenna are not a problem.

  2. Avoid metal near the card backside.
    Keep a minimum distance of 50% of the shortest antenna dimension.
    Example: An antenna dimension of 54 mm needs a minimum distance of 27 mm.

    Coins and other metal parts significantly smaller than the card antenna are not a problem.

  3. Avoid metal around the reader
    You can place the reader on top of metal without any impact. However, when mounting it flush or below metal surface, please stick to the following recommendations.

    ACCESS2xx readers can even be mounted flush into metal without a problem. For this reader type, the guidelines are only relevant when mounted below metal surface.

    • General recommendation:
      Create a cut-out/cavity with a minimum distance of 10 mm around the reader outline.
      Example: With module dimensions of 57x35x9 mm, the minimum cut-out size is 77x55 mm. For a cavity, the depth should equal the module height.
      Diagram: Cut-out with 10 mm distance around BALTECH reader outline

    • ID-1 standard cards:
      In this case, the reader module is significantly smaller than the card. Thus, please create a cut-out with at least the same dimensions as the card: 54x85 mm. Otherwise, the card antenna may be shielded by the metal as it's located close to the card edges.

      Diagram: Cut-out for BALTECH reader outline with size of ID-1 standard cards

    • Cards with smaller antennas:
      If needed, you can reduce the minimum distance to 5 mm around the reader outline.
      Example: For module dimensions of 57x35x9 mm, the minimum cut-out size is 67x45 mm.

      Ferrite shielding

      You may need to place ferrite shielding on top of the metal around the cut-out. We can check if this is needed in your case, e.g. by running a mock-up test in our lab. Just get in touch with us.

      Diagram: Cut-out with 5 mm distance around BALTECH reader outline

Test it thoroughly

A quick test with some sample cards is not enough to test how much metal-free space you need. Even if the result looks good, there may still be communication failures when the system is in use. This is due to variations of card antennas, card IC parameters, and reader RF interface parameters influencing both energy transfer and data communication quality. Please get in touch for individual advice.