The "best" place depends on what you're tagging (an object or a person) and the frequency of the RFID system. Here are the practical guidelines:
1. Sticking RFID on Objects (Most Common)
Avoid These Surfaces
Metal: Causes reflection and detuning. If you must tag metal, use on-metal RFID tags (special foam-backed tags) or stick it on a non-metal part nearby.
Liquid containers: Water absorbs UHF RFID signals. Place the tag on the dry upper portion of bottles, or use HF/NFC tags (which handle liquids better).
Best Practices for Readability
| Factor | Recommendation |
|---|---|
| Orientation | Stick the tag flat and facing the expected reader direction. For conveyor/gate systems, vertical orientation often reads better than horizontal. |
| Height | If passing through RFID gates/portals, stick tags at waist to chest height (3–4 feet / 0.9–1.2m) for optimal read zone coverage. |
| Curves | Avoid wrapping flexible tags tightly around small cylinders (<1 inch diameter) - this can break the antenna. Use curved-surface tags for bottles/cylinders. |
| Corners | On boxes, avoid the exact edges where impact occurs. The center of a side face is usually best. |
2. On the Human Body
If you mean wearable placement (not implantation):
Wrist: Standard for bracelets (comfortable, consistent position near readers).
Back of hand: Good for access control (natural tap position).
Upper arm: Used in hospitals for patient ID; less interference from hand movements.
Avoid: Directly over metal jewelry, watches, or phones, as these can block the signal.
Important Safety Note on "Sticking" to Skin
Adhesive RFID patches exist for events/hospitals, but skin-adhesive RFID is generally for short-term use (hours to days).
Implantable RFID (subdermal chips in the hand) is a specialized medical procedure with specific safety, sterilization, and legal considerations - not a DIY "sticking" application.
3. Quick Reference by Frequency
| Type | Best Placement Strategy |
|---|---|
| UHF (warehouse, logistics) | Keep 1–2 inches away from metal/liquid; flat on cardboard/plastic; height matters for portals |
| HF/NFC (access cards, payments) | Can work through thin materials; less sensitive to orientation; okay near body tissue |
| LF (animal microchips, some access) | Works through body tissue well; typically implanted or embedded |
Bottom line: For objects, stick RFID on clean, dry, non-metallic surfaces at a height and orientation matching your reader setup. For wearables, the wrist or back of hand offers the best balance of convenience and reliable reading.