Some researchers are writing about this technology and saying that it has problems with interference when the product is wet or is placed where we find metal structures, as warehouses.
As far as I know RFID will always have problems with metal - it can't see through metal, and metal reflects and causes dead spots. Water will always be a problem for UHF, but HF and below can see through water because they use the magnetic near-field. Low-frequency tags may even be readable through thin metal foil.
See the note below, for example
http://www.ti.com/lit/wp/slyy056/slyy056.pdf
Dear Priscilla
Metal causes two problems for RFID transponders: It can reflect energy away from the tag, and it detunes the tag antenna, thereby preventing it from receiving energy from the reader.
Water is a bit more challenging, since it absorbs energy and detunes the tag. The detuning issue can be resolved by changing the antenna impedance, so that when it is near water, it becomes tuned to the proper frequency.
Dear Mehdi Imani,
Thank you for your feedback. Do you know or wrote any paper about these problems?
Regards,
I don't know any direct references, but you could try reading articles on electromagnetic shielding and EMC, which is the other side of the problem - which materials stop electromagnetic signals, and how much of the signal gets through , or round, boxes or barriers..
What you want to know is a problem that runs through all communications and radar technology.
Thank, Malcolm, I”ll search articles ablutor thlê-se subjects. I”m supervising an undergraduate thesis, which is about RFID use in hospitals.
There is a good recent paper talking about the interference of other signals on the UHF RFID system as per the attached file.
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