UHF RFID Inlays & Labels

A UHF RFID inlay combines an integrated circuit and an antenna on a thin carrier. It is the functional layer inside an RFID label, hang tag or laminated document. Unlike a barcode, a passive UHF tag can be read without a direct line of sight, and a reader can identify several items within its interrogation zone. Performance still depends on how the antenna is mounted, which reader is used and what surrounds the item.

Dry inlays are supplied without adhesive for converters that add their own layers. Wet inlays add pressure-sensitive adhesive and a release liner. Finished labels put a printable face stock over the same underlying antenna. These are ordering formats for one design, rather than separate antenna models. Specify your label footprint, face material, adhesive and roll requirements when asking for samples, particularly if an existing printer or applicator sets the dimensions you can use.

Chip choice affects memory, encoding and sensitivity. NXP UCODE, Impinj Monza and Alien Higgs families offer different combinations, so compare the actual chip record rather than choosing by brand alone. A sensitivity figure in a chip datasheet describes the bare chip; it does not establish the finished label’s read range. Where a design has several chip options, the available options represent alternatives fitted to the same antenna, not several chips in every tag.

Start with the object, the tagging position and the reader workflow. A long antenna may suit a carton or apparel hang tag; a compact footprint may be necessary for jewelry or small packaging. Ordinary UHF inlays are usually unsuitable when placed directly on metal, and liquids can also change the RF response. Use the on-metal family for metal mounting. Validate shortlisted samples on real items, at the actual reader power and orientation, before confirming a production format and encoding plan.