3M transponder player
By Peter Samuel
3M, the dominant supplier of motor license plate technology around the world is teaming up with Transintel to offer a 5.8GHz transponder that can be built into car license plates. Called an Electronic License Plate (ELP) the product offers police a means of scanning vehicles in a heavy traffic stream to pick out a particular vehicle, or look for vehicles with expired tags using a handheld scanner or reading license plates from a reader located on an overhead gantry, on a roadside pole or with an antenna set in the pavement.
Transintel the designer of the transponder element says the ELP is based on several patents that involve doppler shifting and a new antenna structure. The transponder uses an array of rectifying antenna units that convert energy received to power a new kind of backscatter technology.
Transintel is a joint venture of Schafer Corp and Advanced Power Technologies and is headed up by William H. McDonald, a former senior engineer at Raytheon. The ELP has been tested from stationary up to 180km/hr (112mph). It incorporates a write-once read many times (WORM) identification system with 64 bits. It allows separately encrypted data-frames.
Also part of the joint venture is Equiva Services LLC, a subsidiary of Shell oil company. Shell sees the ELP as a medium for motorists to pay for gasoline and other products at gas stations, including perhaps downloaded videos. It has trademarked the term easyPAY.
McDonald says the ELP deliberately does not make use of the new spectrum at 5.9GHz allocated for ITS in the US but wants the flexibility of the open band at the slightly lower frequency. The ELP com system is claimed to be so well controlled interference is no problem, and there is no need to go into the controlled 5.9GHz area. A presentation on the ELP lists applications as (1) law enforcement (2) traffic monitoring (3) access control (4) electronic tolling (5) m-commerce (m- for mobile) including fuel and convenience drive-up purchasing.