Can Passive RFID Be Read Through Walls?

By RFID Journal

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Ask The ExpertsCan Passive RFID Be Read Through Walls?
RFID Journal Staff asked 5 years ago

Could passive RFID sensors (like those manufactured by Asygn, for instance) transmit a signal through materials such as plastic, metal or wood? In other words, could we interrogate a tag from one room if it were deployed in another room? Assume the rooms to be separated by a door, with the reader and sensor located a few meters apart.




RF energy can travel through some materials, but there are many things that can affect the ability to collect data from a sensor in another room. One is the sensitivity of the chip within the RFID sensor. If the sensor required a lot of energy to respond, or if it responded with a very weak signal, the reader might not pick up the tag's response. If the wall were made of metal, the reader energy would bounce off the wall and never reach the tag. If the wall material were very thick, it might absorb a lot of the RF energy from the reader, thus preventing the energy from reaching the tag. In order to determine whether the sensor data can be collected from a reader in another room, you would need to conduct some testing. In general, I would say it would make more sense to have a reader in the same room to communicate with the sensor.

—Mark Roberti, Founder and Editor, RFID Journal

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