Wet inlay
Inlays
What is it?
A wet inlay is the most basic form of an RFID tag: an RFID chip bonded to an antenna, mounted on a thin PET substrate with a pressure-sensitive adhesive backing. The "wet" refers to the uncured adhesive. Wet inlays are the raw material that converters turn into finished labels, tickets, and hang tags. They are produced in the billions and are the highest-volume RFID product in the world.
How it works
The chip and antenna sit on a PET film typically 50–75 µm thick. An adhesive layer on the underside allows the inlay to be laminated into a label, applied directly to a surface, or embedded into a card or ticket. The antenna design determines the frequency band and read performance – UHF inlays use dipole or dual-dipole antennas, while HF inlays use a coil antenna.
Use cases
- Retail item-level tagging
- Apparel hang tags
- Supply chain carton labels
- Library books
- Event tickets
- Smart packaging
Pros
- Lowest per-unit cost (sub-$0.05 at volume)
- Extremely thin and flexible
- Easy to convert into labels, tickets, and cards
- Massive selection of chip and antenna combinations
Cons
- No environmental protection – the IC is exposed
- Not suitable for harsh environments without additional packaging
- Poor performance directly on metal or liquids without spacer
- Adhesive may degrade at temperature extremes
Specifications
| Power type | Passive – powered by reader signal |
|---|---|
| Frequency | UHF (860–960 MHz) or HF (13.56 MHz) |
| Read range | UHF: up to 12 m; HF: up to 10 cm |
| Lifespan | 5–10 years depending on environment |
| Price range | $0.03–$0.15 per unit at volume |
| Environmental rating | Indoor / controlled environments only |