UHF RFID Inlays: Dry and Wet

Dry or wet: which inlay format to order

Order a dry inlay when your own process laminates or embeds it: paper tickets, hangtags, PVC or PET cards, wristbands, or labels with your own adhesive. Order a wet inlay to convert into self-adhesive labels or to apply directly as a sticker. For printed labels, see UHF RFID labels.

A common construction is an etched aluminium antenna on PET film with the chip bonded at its feed point. The quotation states the carrier, antenna and outline of the inlay we offer.

Chip options and datasheet figures

Choose the chip by memory and features first, then compare sensitivity. Every chip below follows the GS1 EPC Gen2 air interface standard, harmonised with ISO/IEC 18000-63, so any Gen2 reader operating in the tag's band can inventory it. The chip changes memory, sensitivity and security features, not the reader.

Sources: NXP data sheets for UCODE 9 and UCODE 9xe, NXP's UCODE Nxm page, Impinj's M700 and M800 spec tables and Alien's Higgs-9 page. The UCODE 9 and 9xe data sheets and Alien quote sensitivity on a 2.15 dBi antenna; Impinj uses its own modelling and test data. A 1 dB gap on paper does not predict read range on your items.

Chips not to design in: NXP lists UCODE 8/8m as no longer manufactured and UCODE 9xm as end of life. If an existing specification names one, the quotation proposes a current chip with the memory you use (UCODE 9xe in place of UCODE 8; Impinj M750 or M850 in place of UCODE 8m; UCODE Nxm, Impinj M780 or M781 in place of UCODE 9xm), and samples are tested on your items before the switch.

NXP UCODE 9 in brief: a 96-bit EPC delivered pre-serialised, no user memory, a factory-locked 96-bit TID including a 48-bit unique serial number, read sensitivity −24 dBm and write sensitivity −22 dBm on a 2.15 dBi antenna, a 32-bit kill password and an access password hardwired to zero (NXP data sheet). The pre-serialised EPC copies the TID, so it is not a GS1 identifier.

Three memory details catch buyers who change chips. UCODE 9 and UCODE 9xe have no usable access password. Impinj lists the access and kill password as shared on every M700 and M800 chip; its M730/M750 datasheet explains that one 32-bit value serves both, so check how your encoding software sets them. And the TID, which records the chip maker and model, changes with the chip, so software that filters on TID values must be updated first. SGTIN-198 needs more than 128 bits of EPC memory (GS1 TDS), which points to M780, UCODE Nxm or Higgs-9.

Antenna design follows the application

The antenna matters as much as the chip. Each design is tuned for the material it sits on or near, so an inlay that reads well on a carton can read poorly on a bottle of water. We propose the antenna for your application and confirm its dimensions per order.

Chip features such as Impinj's AutoTune or NXP's Self-Adjust help at the margins but do not replace an antenna chosen for the item; test samples on the real item with the real reader.

Region tuning: ETSI, FCC or broadband

A UHF inlay antenna is tuned to the band where its tags will be read: 865–868 MHz in Europe under ETSI EN 302 208 and 902–928 MHz in the United States under 47 CFR 15.247. A broadband design covers both, with samples tested at each band. To find the band for another country, use our UHF RFID frequency lookup, which lists the bands and reader power limits GS1 gives for each country in its overview.

NXP describes UCODE 9 and UCODE 9xe as broadband chips for global labels; performance in each band still depends on the inlay antenna.

Roll format, confirmed per order

Roll format must match your press, laminator or printer, so it is confirmed per order. Send your line's requirements or a sample roll of your current inlay.

For encoded inlays we write the EPC from your list through the RFID encoding service, following the GS1 EPC Tag Data Standard, for example SGTIN-96; locking and passwords depend on the chip.

Inlay testing and defect handling

Inlays are tested before dispatch by the method agreed for your order, and inlays that fail are marked or removed as agreed. Settle the details before the first run:

• Test: a read or read-and-write check, EPC verification for encoded inlays, and the test frequency.
• Defects: how a failed inlay is marked, or whether it is removed and replaced, and whether splices are acceptable.
• Tolerance: the defective inlays per roll your line can accept; the quotation states what we commit to.
• Records: a TID/EPC export for encoded inlays, if your software needs one.

Switching inlay suppliers

Qualify a new inlay in your application before it replaces the current one: match the chip and memory map first, then compare reads on your items with your readers.

1. Describe the current inlay: chip, antenna footprint, pitch, roll format and any retailer specification it was approved against.
2. Check your software: EPC length, user memory, passwords, locking and any rule that filters on TID values.
3. Keep serials unique: if both suppliers deliver encoded inlays, give the new one a non-overlapping serial range under the same EPC scheme.
4. Run qualification samples side by side with the current inlay on the same items, reader, antennas, power settings and tag positions, recording reads and misses.
5. Run a converting trial on your line: pitch registration, die-cutting, lamination and encoding yield.
6. Check retailer approval. Auburn University's RFID Lab publishes ARC approved inlay lists by the specification your retailer names. Approval belongs to a specific inlay model on the list for that spec; a similar test result does not count. Name the spec in your RFQ: before sampling we tell you whether the inlay we offer is on the approved list for that spec, and the quotation names the inlay model so you can check the current list. Where the spec calls for an approved inlay that is not ours, we can convert that ARC-approved inlay into your labels or hang tags.
7. Approve a reference: keep the approved sample and specification sheet; reorders are produced against them.

Ordering checklist: what to send for a quote

Send what you know; anything missing is resolved before sampling. We reply with a quotation within one business day of a workable enquiry.

• Format: dry inlay, wet inlay or finished labels.
• Chip: a named chip, or the memory and features you need.
• Application: the item, its material and contents, where the inlay goes and the maximum inlay size.
• Region: the countries where tags are read, and your reader make and model if known.
• Roll format: pitch, rows across, core, roll size and winding, or a sample of your current roll.
• Your process (dry inlays): lamination or embedding method (hot or cold, temperature and pressure if known), finished product, die-cut tolerance and any registration or sensor mark your line needs.
• Adhesive (wet inlays): surface, application temperature, permanent or removable.
• Encoding: as delivered, or encoded to your EPC scheme. Never send password values in an enquiry.
• Quantities and delivery: sample, first order and annual volume, destination and target date.

What we confirm per order

The quotation or the approved sample fixes these points for each order; nothing is assumed from a catalogue.

What Proud Tek makes, and what it does not supply

Proud Tek produces dry and wet UHF inlays, UHF RFID labels and custom RFID tags in its Shenzhen factory, and encodes them to order. We do not supply UHF fixed or handheld readers, reader antennas, RFID printers or encoders, race-timing systems, BLE beacons, or software and WMS integration; our reader range contains no UHF readers. For the wider programme, see RFID inventory tracking, RFID for retail and apparel and RFID supply chain management.