RF power to energise transponders is generally limited to between 0,5 and 2 W in most countries by the national regulators. At the same time as RFID reader technology merges into realtime locating system (RTLS) technology, the user would like to have longer and longer operating ranges so that they can monitor larger areas with fewer readers.
RF power to energise transponders is generally limited to between 0,5 and 2 W in most countries by the national regulators. At the same time as RFID reader technology merges into realtime locating system (RTLS) technology, the user would like to have longer and longer operating ranges so that they can monitor larger areas with fewer readers.
UHF frequencies, by the laws of nature, allow long operating ranges with practical antenna sizes. Operating range is a function of efficiency of the antennas, which means that antenna sizes will have a dimension of about 16 centimetres at these frequencies - the half-wavelength dimension.
Trolley Scan has announced that it is currently testing a new design for a battery-assisted credit card-sized tag that will operate at 35 metres. The new tag is similar to the Claymore tag provided to Trolley Scan's RFID-radar users in that it contains a fair volume of polypropylene plastic to try to make the transponder more neutral to the influence of being attached to items that they are tagging. Generally, items that are in the near field zone of a transponder will influence the performance of the radio waves in the vicinity of the tag, and the challenge is to neutralise these effects, while keeping very low operating energy requirements and small size.
These tags are not 'active tags' in the sense that they do not transmit any signal from the tag. They reflect some of the energy arriving from the energiser of the reader back to the reader at the same frequency. This means that the tags will respond to multiple readers simultaneously and correctly if the readers are operating on slightly different frequencies and are in close proximity to each other. Trolley Scan says that this frequency-agile property allows many reader systems to monitor correctly the same zone with overlapping fields, and it allows for goods to be tagged in one country and then be read correctly in another country at a very different operating frequency.
These tags are still being tested, Trolley Scan says it will not supply them with current systems until all hurdles are sorted out. They will be compatible with all existing RFID readers and RFID-radars supplied by the company.
Because Trolley Scan products have a wide range of packaging options and operating sensitivities, they are being used in a wide range of applications by users in 49 countries. They operate at long ranges, large numbers of transponders are allowed in a zone, they are very fast to respond and allow maximum speeds up to 300 km/h, and also, the readers are simple to interface to software. The same transponders will operate with Trolleyponder RFID reader systems if just identification is needed, or with its RFID-radar system, if realtime locating is needed.
According to Trolley Scan, users of the technology typically are: farmers managing a herd, a vehicle garage managing access for regular clients, a company managing the movement of its laptop computers, a library managing its books and lenders, access control systems for staff, a trucking company monitoring usage of its vehicles, a car hire company checking to see the tyres supplied on its vehicles have correctly been returned, an industrial laundry managing the washing of gowns and overalls for a factory, or even a logistics company managing parcels passing through its warehouse.
For more information contact Mike Marsh, Trolley Scan, +27 (0)11 648 2087, [email protected]
| Tel: | +27 10 237 0675 |
| Email: | [email protected] |
| www: | www.trolleyscan.com |
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