At What Depth Can an Underwater Active Tag Be Read?

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Ask The ExpertsAt What Depth Can an Underwater Active Tag Be Read?
RFID Journal Staff asked 11 years ago

Can an active 2.4 GHz tag be interrogated underwater (salt water and sweetwater) by an RFID reader located above the surface?

—Name withheld


I know of no deployments in which active tags have been used underwater, and I have not seen any tests conducted on the use of active RFID in such a scenario, so I am unable to provide the distance at which active tags can be read.

I believe the reason few deployments have been carried out with active tags underwater is that active RFID systems suffer from the same issue as passive ultrahigh-frequency (UHF) technology: Water absorbs electromagnetic energy in this frequency range. In fact, microwave ovens use 2.4 GHz to heat up food. So I would guess that the read range would be very short—a couple of feet—if you could interrogate the tag at all under such conditions.

—Mark Roberti, Founder and Editor, RFID Journal

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