Zebra’s RFID Smart Label Overview
Tips for RFID Smart Label Printing/Encoding
Selected excerpts from the Zebra Technologies White Paper.
RFID Smart Label Overview
Printable RFID tags contain a low-power integrated circuit (IC) attached to an antenna, and enclosed with protective material (label media) as determined by the application. On-board memory within the IC stores data. The IC then transmits/receives information through the antenna to an external reader, called an interrogator. High frequency (HF) tags use antennas made of a small coil of wires, while ultrahigh frequency (UHF) tags contain dipole antennas with a matching wire loop.
Depending on the application, users sometimes call tags transponders or inlays. Technically, an inlay is a tag on a flexible substrate that is ready for conversion into a smart label. RFID tags come in many forms and sizes, some as small as 10 x 10 mm. Traditional RFID printer/encoders often require an inlay pitch of 50 mm or more to ensure accurate data encoding. Pitch is the distance from the leading edge of an inlay to the leading edge of the next inlay on the printing web. Shipping compliance and immature chip technology originally drove the 50 mm requirement. Most RFID printers available today contain older RF encoding technology designed for legacy applications such as pallet tracking, forcing them to support a minimum inlay pitch of only 50 mm.
Pitch depends on the inlay size, and the smallest inlays today use a 16 mm pitch. Unfortunately, traditional RFID printer/encoders cannot take advantage of these reduced-pitch inlays. As a result, the label converter must add an extra process to space out the inlays prior to encoding or tagging, which adds unnecessary overhead to media costs.
Passive tags receive all of their power from the external tag reader, allowing the tag to “wake up” and transmit data. Quite frequently, manufacturers optimize tags for long-range and robust read rates, with the goal of reading hundreds of tags at once, sometimes several meters away. However, a printer/encoder’s task is unique—the goal is to encode one specific tag, in the close vicinity of hundreds or even thousands of other tags—not an easy task.