User Manual

CHAPTER 5: RFID TAGS
COBALT HF RFID CONTROLLERS OPERATOR’S MANUAL
P/N: 17-1320 REV 01 (03-06) PAGE 55 OF 116
5.3 RFID TAG PERFORMANCE
Many factors can affect the performance between the controller’s antenna and the tag’s
antenna. These include, but are not limited to: the tag integrated circuit (IC), the antenna
coil design, the antenna conductor material, the antenna coil substrate, the bonding
method between tag IC antenna coil, and the embodiment material.
Additionally, the mounting environment of the tag and controller can hinder performance
due to other materials affecting the tuning of either antenna. Escort Memory Systems has
undergone extensive testing to produce tags that obtain optimum performance with our
RFID controllers. In most cases, optimal range will be obtained when mounting the tag
and controller antenna in locations free from the influence of metals, ESD and EMI
emitting devices.
5.4 RFID TAG EMBODIMENTS
RFID tags come in a variety of sizes and packages. The most common and cost effective
tag embodiment is the RFID label.
5.4.1 RFID Labels
RFID Labels (inlays or inlets) are the lowest cost RFID tag solution and are typically used
in an open system in which the tag leaves the facility attached to a product or is
destroyed at the end of the process.
An inlay is a substrate (made of polyester or Mylar) with a
printed, screened or etched antenna coil. Sometimes the
coil consists of a wire that is laid down onto the substrate
and is bonded to it with heat. Typically, the RFID IC is
attached by means of flip-chip technology and the
electrical connections are made by means of conductive
epoxies.
RFID inlays are usually applied to sticker backed paper to
create label tags which are manufactured in high volumes
on roll-to-roll production equipment. Inlays can be
laminated an used in smart credit cards, providing a low
cost RFID tag with some protection from impact damage.
The materials and procedures used to manufacture an RFID label’s antenna coil are
critically important. Low cost processes (such as printing or screening) produce low
quality antenna coils which can exhibit poor conductivity and cracking when flexed.
Labels with copper wire wound coils are generally considered efficient conductors of RF
energy and can usually survive considerable flexing, but are often more expensive due to
more involved production processes.
RFID labels with etched copper antenna coils have been found to be the most reliable,
semi-low cost tag solution. Etched inlay antenna coils are usually of consistent quality
and can survive a great deal of flexing and bending. However, because etching is
inherently a subtractive process, the cost per tag increases in part due to copper and
other metals discarded during the fabrication process.
As RFID label manufacturing technology advances, there have been several new
developments made in the areas of high volume, low cost, antenna coil manufacturing.