Can RFID Tags Be Read Back to Back?

We have a customer that wants to be able to read up to 500 tags simultaneously within very close proximity of each other. The tags are attached to pieces of leather and may be placed back to back. I have spoken to an RFID manufacturer, which told me this would be problematic, for if tags were placed back to back, they might not be read correctly or even at all. Is this the case for all RFID tags, or could the problem have something to do with the company’s specific equipment?

—Peter

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Peter,

It would depend on the types of tags you are using. If you wanted to read tags from a distance of 10 feet or more, you would need to use passive UHF RFID transponders, and it would be difficult to read those consistently if the tags were stacked one on top of another or back to back. The metallic antenna of one tag would likely block the energy from reaching the tag below it.

However, Magellan Technology developed a technique called phased jitter modulation, enabling HF tags to be read even if they were stacked one on top of another. These tags can be read from a distance of 1 or 2 feet. If that is all the read distance you require, I would suggest you contact  SATO Holdings Corp., which acquired Magellan in 2013.

Mark Roberti
Founder and Editor
RFID Journal