How are RFID tag comparisons structured?

Each comparison provides a side-by-side analysis of two RFID tag ICs or technologies, covering memory capacity, read sensitivity, read range, protocol features, pricing, and recommended applications. A summary recommendation helps you quickly decide which option fits your requirements.

What is a cross-technology comparison?

Cross-technology comparisons evaluate RFID against other identification technologies such as barcodes, QR codes, NFC, BLE beacons, and GPS. These help you decide whether RFID is the right technology for your use case or if a combination approach would be more effective.

Near-Field vs Far-Field UHF — การเปรียบเทียบ RFID

Near-Field vs Far-Field UHF RFID: Reader Antenna Physics Explained

Within UHF RFID, the distinction between near-field and far-field coupling is not just an academic exercise — it determines whether a tag works at all, and explains why EPC Gen 2 UHF tags fail at extremely close range in certain configurations while performing optimally at several metres.

Overview

UHF RFID fundamentally uses far-field electromagnetic coupling: the reader antenna radiates RF energy outward, and the tag's dipole antenna intercepts that energy, rectifies it to power the chip, and modulates backscatter to communicate. This is a far-field, radiation-based interaction optimised for read ranges of 0.5–12 m.

However, UHF near-field RFID is also a defined product category. Specialised near-field UHF antennas generate a predominantly magnetic field (similar to HF RFID coupling physics) at close range (~0–10 cm), specifically for applications where precise, controlled reading of a single item without reading adjacent items is required. Near-field UHF antennas are used in pharmaceutical item-dose dispensing, POS read zones, and smart shelf reading where isolation is critical.

Key Differences

Coupling mechanism: Far-field UHF couples via electromagnetic radiation (E-field dominant). Near-field UHF uses a special antenna geometry (loop, ferrite-loaded) to couple inductively (H-field dominant) at very close range.
Read range: Far-field UHF: 0.5–12 m. Near-field UHF: 0–10 cm with very precise read zone control.
Read zone isolation: Far-field readers see everything within their antenna pattern — useful for bulk reads, problematic when reading only one specific item among adjacent tagged items is required. Near-field UHF is specifically designed to read only the tag within the defined read zone.
Tag compatibility: Far-field EPC Gen 2 tags optimised for far-field coupling (dipole or patch antennas) perform poorly at near-field UHF read points. Near-field UHF requires tags with near-field antenna designs (loops or compact dipoles).
Application: Far-field: dock doors, conveyors, retail handheld sweeps. Near-field: pharmaceutical dispenser verification, POS scan points for individual item identification, smart shelving.
Interference with adjacent items: Far-field reads all items in the field — including unintended ones. Near-field controls zone precisely — only the item in the read zone responds.

Technical Comparison

Attribute	Far-Field UHF RFID	Near-Field UHF RFID
Coupling mechanism	Electromagnetic radiation (E-field)	Inductive (H-field dominant)
Read range	0.5–12 m	0–10 cm
Read zone isolation	Low (reads full antenna pattern)	High (controlled zone)
Tag antenna design	Dipole / patch (far-field)	Loop / near-field specific
Tag compatibility	Standard EPC Gen 2 dipole tags	Near-field UHF specific tags
Application	Bulk reads, dock doors, handhelds	Item isolation at dispenser, POS
Anti-collision demand	High (hundreds of tags)	Low (typically single tag)
Frequency	860–960 MHz	860–960 MHz (same!)
Standard	EPC Gen 2, EPC Gen2 UHF standard." data-category="Standards & Protocols">ISO 18000-63	EPC Gen 2 (same, different antenna)
RFID chip	Identical	Identical

Use Cases

Far-field UHF excels when: - Bulk reads of many items simultaneously are the primary requirement (dock-door pallets, retail inventory sweeps, conveyor reading) - Items do not need to be individually isolated — reading all tags in a zone is the objective - Long read range to cover a large portal or shelf area without precise positioning is needed

Near-field UHF excels when: - Precisely reading only the item presented to a specific read point is required, without triggering adjacent tags - Pharmaceutical dispensing verification must confirm the specific unit being dispensed, not adjacent units on the shelf - Smart shelf reading of individual slots requires isolation between adjacent tagged items - POS RFID pads need to read the item placed on the pad without reading items nearby

When to Choose Each

Choose far-field UHF for all standard supply-chain, retail inventory, and logistics applications. The bulk read capability, long range, and ecosystem maturity of standard far-field EPC Gen 2 make it the right default for 95 % of UHF deployments.

Choose near-field UHF for precision dispensing, item isolation, or smart shelf applications where reading adjacent tags would cause operational errors. The additional cost of near-field antenna design and compatible tag selection is justified by the precise read-zone control.

Conclusion

Near-field and far-field UHF RFID use the same chips and the same EPC Gen 2 protocol — the difference is in the antenna design and coupling physics. Far-field is the default for supply-chain scale and long-range bulk reads. Near-field is the precision instrument for applications requiring controlled read zones at close range. Both are important tools in the UHF RFID toolkit; the selection criterion is whether bulk reads or isolated single-item reads are the operational requirement.