On-metal tag
Hard tags
What is it?
Standard RFID tags fail on metal surfaces because the metal reflects and detunes the antenna. On-metal tags solve this with a spacer layer (foam, ceramic, or FR4 substrate) that separates the antenna from the metal surface and uses the metal as a ground plane to actually boost performance. Some on-metal tags read better on metal than off it.
How it works
A dielectric spacer (typically 1–3 mm thick) is placed between the antenna and the metal surface. The spacer prevents the metal from shorting the antenna fields. The antenna design is specifically tuned to use the metal surface as a reflector – a patch antenna or microstrip design that turns the metal into part of the antenna system. This is why on-metal tags often have better range on metal than generic tags have in free air.
Use cases
- IT asset tracking (servers, laptops)
- Tool tracking
- Metal container and pallet tracking
- Aerospace parts
- Automotive manufacturing
- Industrial equipment maintenance
Pros
- Designed specifically for metal surfaces
- Often achieves excellent read range despite metal
- Rugged construction for industrial environments
- Long lifespan – typically 10+ years
Cons
- Significantly more expensive than inlay-based tags
- Thicker and bulkier than labels
- Specific antenna tuning may limit cross-surface compatibility
- Not flexible – rigid construction
Specifications
| Power type | Passive – powered by reader signal |
|---|---|
| Frequency | UHF (860–960 MHz) or HF (13.56 MHz) |
| Read range | UHF: 1–8 m; HF: up to 5 cm |
| Lifespan | 10–25 years |
| Price range | $1–$15 per unit |
| Environmental rating | IP65–IP68 depending on model; -40°C to +85°C typical |