Apr 23, 2009Is there a way to read RFID passive tags worn by individuals sitting in a vehicle? In other words, is an interrogator able to read a tag within a metal vehicle?
—Name withheld
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The answer depends on a number of factors, including the type of tag used, the tag's location and the position of the reader antennas.
If you are trying to read a passive tag in a wallet on which a driver is sitting, for example, and if you position an interrogator below window height, you will not be able to read the tag. If you hang the tag around a person's neck, on the other hand, and position several reader antennas to read through the side windows and front windshield, you can probably read an ultrahigh-frequency (UHF) passive tag fairly consistently. An active tag broadcasts its signal, and would thus offer the best opportunity to capture the IDs of those within the car.
The U.S. government has been using passive UHF tags at the country's borders with Canada and Mexico, in order to capture the IDs of travelers. The government asks that those crossing either border hold up an ID card upon approaching a checkpoint. The tag ID is associated with information in a database that is called up on the screen of a border patrol agent. This is probably the best way to ensure reads of passive tags.
I would be interested to hear from any readers who might have some experience with this.
—Mark Roberti, Editor, RFID Journal