Given that the read range of RFID is affected by water absorption, how can I overcome heavy rain conditions for toll-collection stations?
Many toll-collection agencies use active RFID transponders in vehicles. Active tags broadcast a strong signal to a reader affixed above a toll-collection station. Water will not be an issue with this kind of system.
If you are considering using passive UHF RFID, as more and more toll-collection agencies seem to be doing, then water absorption could pose an issue. The solution would be to cover the toll area, so that the car, tag and reader antenna would remain dry while the tag was being read. You would also need to position the tag and reader in closer proximity to one another than would be required in an arid climate. One option would be to place the tag on the front license plate and locate the reader antenna or antennas to the left or right of the vehicle, angled toward the plate. Having the antenna at the same height as the plate would likely enable you to read the tag from a height of just a few feet.
I would encourage you to find a good RFID company that can work with you to test a few different toll-collection application designs and find one that will work for you 100 percent of the time under all conditions. On Apr. 2-4, we'll be hosting our RFID Journal LIVE! conference and exhibition at Arizona's Phoenix Convention Center. This would be a good place for you to talk to the top companies that design and sell tags for vehicles, as well as reader companies that could advise on the best way to achieve 100 percent read rates, even in driving rain (pun intended).
—Mark Roberti, Founder and Editor, RFID Journal
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