Trolley Scan Delivers Passive UHF RFID Transponders That Operate On Just 200 Microwatts Of RF Power

Trolley Scan announced in Johannesburg that they have crossed another major technical hurdle in the development of long range, efficent, low cost, passive RFID systems.

As part of leading the way in the development of passive UHF RFID, Trolley Scan have developed new materials that allow for the production of transponders in volume that need just 200uW of RF energy to operate. This represents a 42% improvement in the sensitivity of transponders supplied by Trolley Scan in the past. All credit card sized Ecochiptag transponders supplied by Trolley Scan will now need only 200uW of power to operate.

Said Mike Marsh, MD of Trolley Scan, "Improving transponder sensitivity is like improving fuel consumption for a car - you can never have enough. Every time the sensitivity improves, it means that the transmitted power of the reader can be further reduced needing smaller transmitters to do the same job with longer battery life - or the operating range of the transponder system increases. The new production transponders can be read 8 meters from a reader radiating just 300 milliwatts of power, similar to the power radiated from a cell phone. In addition, due to the miniscual amount of power needed to operate the transponder, polarisation becomes less important and transponders can be read on almost any orientation even with linear polarised antennas. The 8 meter range is achievable even if the transponder is attached to metal."

In 1994 a state of the art transponder used in the original Supertag version developed by a team led by Mike Marsh, and shown to the world with a trolley(cart) of 38 items being scanned at the Pick n Pay hypermarket in Pretoria South Africa, needed 6000uW of RF power to operate. In 2001 Trolley Scan started delivering 1000uW versions with its evaluation systems. In December 2003, Trolley Scan delivered 350uW credit card sized versions, a major technical achievement as the previous systems all needed 160mm dipoles while the credit card sized version was only 80mm long - a size that is inherently inefficient at this operating frequency. Now the norm with the latest developments is 200uW in a credit card sized version.

Comparing the performance to the original Supertag tests, the transmitter power needed now is only 3% of that needed for the original system, meaning smaller transmitters, longer battery life and portable readers. The operating range at the original power used for Supertag is 550% of the ranges then achieved.

Despite the benefits of long operating range and low transmitter power, the Trolley Scan has maintained all its important benefits such as wide operating bandwidth (50MHz for EU/GSM/US compatibility), up to 500 multiple transponders in the reading field, 3D scanning small antenna size and easy to produce.

Trolley Scan provide RFID systems to users in 32 countries. Complete systems can be ordered via their website.

About new generation RFID Transponder
Passive RFID works by the reader sending out a low power beam of energy which dissipates with distance travelled; part of which is collected by the transponder and converted to power to operate the transponder; the transponder using some of this energy to send back its identity data on the same frequency as the energising signal.

The reader has to be able to detect the data from the transponder while in the presence of the energising signal which is powering up the transponder. The two signals differ is strength by up to 1 billion times (90dB).

As the energy from the reader travels through the space between the reader and the transponder, it dissipates such that every time the distance doubles, the available energy to power up the transponder quarters. Therefore producing transponders that need lower power mean they can still operate at increased ranges.

About EcoTag technology
The Ecotag development achieves some major breakthroughs

The credit card sized version is a technology breakthrough allowing both very efficient transponder operation while allowing small transponder antenna sizes.

A typical efficient UHF antenna will be 160mm long. However the market wants shorter antennas that are closer to the sizing of goods being labelled. Shortening a 160 millimeter antenna to 80 millimeters results in only 3% of the efficiency being left. The impact of shortening antennas is of great concern to the UHF RFID producers as the challenge is to increase efficiency in order to get greater coverage and range. Trolley Scan have developed an 80mm by 37mm flat antenna that recovers this lost efficiency as well as increasing the performance of the chip, allowing a transponder that now needs only 200 uWatts of RF energy to operate, making it one of the most energy efficient transponders available in the world.

Despite its excellent performance, the credit card sized version is produced in a single plane and is ideal for production using conductive inks applied with a printing press. This is an important development as eventually for volume application of RFID, the antennae are going to be made directly on the packaging.

The new Ecotag credit sized version now can operate at ranges as far as 11 meters, even when attahed to metal.

EcoTag technology is protected by a series of patents granted in the US, Europe and other countries.

About Trolley Scan (Pty) Ltd
Trolley Scan have proven to be a major creative force in the development of UHF RFID technologies. These developments have been protected by patents which have been offered to the global manufacturing industry to impliment. Founded in 1995, the staff of Trolley Scan have a pedigree that goes back to 1990 when the first low cost RFID protocol was developed by the founder while working for a South African government research organisation, culminating in 1994 in the demonstration of a supermarket trolley containing 38 items being scanned automatically in a supermarket in Pretoria. In 1998, the founders of Trolley Scan developed an entirely new set of protocols for UHF RFID which they have been actively promoting. They also have addressed the situation of the 3 dimensional scanning of goods, and have developed a very low power RFID version which they commercialise under the EcoTag trademark. Trolley Scan is based in Johannesburg South Africa.

Trolley Scan licences their patents and technology to companies around the world who wish to produce this technology. Trolley Scan have already provided systems using this technology to users in 32 countries.

About UHF RFID
RFID systems comprise of a transponder that is attached to the goods to be identified and a reader that converts the information in those transponders to a computer compatible format for processing. The transponder can comprise of a simple antenna and a small integrated circuit that can be produced at low cost. Operating in the 860 to 930 MHz (UHF) band, the transponder can be identified meters away from the reader, can be identified in a group with up to 1000 other transponders when being read, and can be identified very quickly. In view of the system using radio waves for energy and information transfer, it is not necessary for the transponder and reader to be in line of sight.

Potential use of these systems is extensive, from herd animal tracking, library books, pallets, warehousing, bank and postal bags, asset tracking, airline luggage, vehicle monitoring (access and parking), to intelligent buildings (tracking files, documents and assets moving around an office to minimise finding time).

The ultimate goal is to use these transponders with their inbuilt anti-shoplifting features to replace the barcodes labelling goods in a retail store allowing filled supermarket trolleys to be scanned in seconds in unmanned self service checkout aisles.