In actual deployments, not all metals have the same absorption rate of electromagnetic waves. Metals with higher permeability and conductivity will have a stronger shielding effect on signals. The following is a comparison of interference tests conducted in a standard laboratory environment using anti-metal NFC tags of the same specifications:
| Metal Material | Signal Interference Level | Recommended Anti-Metal Layer Thickness | Measured Sensing Distance Recovery Rate* | Typical Application Scenarios |
| Aluminum | Extremely High | ≥0.3mm | Approx. 65% | Phone Cases, Aluminum Foil Packaging, Cans |
| Copper | High | ≥0.3mm | Approx. 70% | Heat Sinks, Cable Sheaths, Circuit Boards |
| Stainless Steel | Medium | ≥0.2mm | Approx. 85% | Kitchenware, Laboratory Equipment, Escalators |
| Iron/Mild Steel | High (Magnetic Interference) | ≥0.2mm | Approx. 75% | Factory Machinery, Shelves, Toolboxes |
| Titanium Alloy | Medium | ≥0.2mm | Approx. 80% | High-End Electronic Products, Medical Devices |
**Note: Measured Sensing Distance Recovery Rate This refers to the percentage of sensing distance when an anti-metal tag is attached to a metal surface compared to when a regular tag is in a non-metallic environment.
💡 In-depth analysis: Why are aluminum and copper the most difficult to handle?
- High conductivity barrier: Aluminum and copper are excellent conductors. When electromagnetic waves at 13.56 MHz encounter them, they generate extremely strong reverse electromagnetic fields (eddy currents). This requires anti-metal tags to have ferrite materials with higher magnetic permeability to forcibly change the path of magnetic field lines.
- Special properties of magnetic metals: Iron and ordinary steel, while having slightly lower electrical conductivity, have high magnetic permeability. They “attract” magnetic field lines, causing detuning of the tag antenna.
- Advantages of stainless steel: Most stainless steels (such as 304 or 316 grades) are non-magnetic or weakly magnetic, and have low electrical conductivity, thus causing relatively less interference to NFC signals.
🛠️ Deployment Recommendations for B2B Clients
- For aluminum/copper surfaces: We recommend prioritizing the purchase of rigid anti-metal tags or specially formulated high-performance stickers with a thickness of 0.5mm to ensure basic read redundancy.
- For stainless steel surfaces: Ultra-thin anti-metal stickers can be selected, achieving good sensing distance while maintaining aesthetics.
- For mobile devices: If applying to the back of a phone, due to interference from the integrated aluminum alloy frame and battery, the NTAG213 25mm or 30mm circular anti-metal sticker is the most stable and market-proven solution.
For more information,please contact us.
