Can Any Passive UHF Tags Be Read From More Than 100 Meters Away Using a Conventional Reader?

We are a supply chain solution design firm, and are working on a system that requires passive tags with a very long reading distance. These cannot be battery-assisted passive RFID or active RFID, due to maintenance issues. I heard there is some technology available in the United States. Do you have some ideas about that?

—Ce

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Dear Ce,

There are no passive UHF tags that can be read at more than 100 meters (328 feet) using a conventional RFID interrogator. Omni-ID's Ultra tag has the longest read range of any passive UHF tag of which I am aware (see Omni-ID Launches New High-Performance UHF Gen 2 Tags). It can be read at a distance of about 35 meters (114 feet).

There are phased-array antenna systems that separate the send and receive functions of a conventional RFID reader system, enabling one to read passive tags from more than 100 meters away. Mojix's STAR system has devices called eNodes that energize a tag, but do not receive a signal (see The Brightest Star and Mojix Announces the Availability of Its Next-Generation RFID System). Rather, a single phased-array antenna is able to pick up the tag's faint signal from far away. This is the only system of which I am aware that can interrogate passive tags from a distance of more than 100 meters.

—Mark Roberti, Founder and Editor, RFID Journal