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?
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
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