September 26, 2005
UHF Vs. HF tags
Item level tagging with RFID has been conducted mainly with HF (13.56 MHz) tags. There are more than one billion HF tags already in use. Even though UHF is also being trialed widely, most enterprises such as Metro in Germany, FDA in the US have favored HF tags with write capacity. In Europe, DHL has invited bids for 1 billion HF tags for consumption every year.
The Swiss packaging company, Zeiler, which is supplier to Roche, has teamed up with Siemens to develop HF tags that will be used on ampoules and syringes. GCC, which is a chain of supermarket stores in the Middle East, is planning to tag every item in one of its stores by September 2005. The HF tags for the trial, which is expected to last for six months, will be provided by the Emirates Technical Innovations Centre ( ETiC).
There are some retailers who prefer to use UHF tags for item-level tagging as they are already using the higher frequency UHF tags on cases and pallets. Tesco, for example, has delayed item-level tagging even though it obtained excellent results with HF tags. The companies wish to duplicate the success with UHF tags. The tag manufacturing companies such as Tagsys recommend HF tags for item-level tagging but most companies are currently concentrating on meeting the pallet-level tagging mandates of major customers such as Wal-Mart.
Even though certain readability and quality issues have to resolved regarding HF tags, the project by ETiC gives it a unique opportunity to conduct a trial in a large retail environment and learn about item-level tagging, specifically of food and other perishable items. GCC will use tagging to manage the supply chain across its 68 stores. ETiC is aiming to establish a production facility with a capacity of more than 1,200,000,000 tags/year. The facility will manage the assembly and attachment of the tags and will be able to provide self diagnostic strips, smart labels, time and temperature labels, etc.
In laundries, item-level tagging is done by using HF tags as the wet conditions preclude the use of UHF tags. Items in libraries are also tagged using HF tags. Japanese radio regulations do not permit the use of UHF for RFID; therefore Maruetsu, which is a prominent Japanese chain of stores, uses HF tags for tagging its food items. UHF finds use in conditions where a longer range is required and there are no metals in the vicinity, for example, in apparel stores. Also, UHF is being tested for item-level tagging in the pharmaceutical industry.
UHF tags use an antenna that is easier to produce because its specifications for conductance are easier to meet. This could give UHF tags an edge in costing. However, the royalties that need to be paid to Intermec will be a factor that will add to the cost of UHF tags. UHF antennas, E-Field, have to be half wavelength and are larger than HF antennas that are H-Field.
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