Can an economical one-to-one RFID solution be used to detect if an object moves outside a defined area—say 100 millimeters (3.9 inches)?
I’m unsure what you mean by a “one-to-one RFID solution.” But yes, you could probably do this using radio frequency identification. You could create a passive high-frequency (HF) reader antenna that would cover 100 square millimeters (0.16 square inch) and put a tiny HF tag on an object. The smallest HF tag on the market is Murata‘s LXMS33HCNG-134, which measures 3.2 millimeters (0.13 inch) in width and length and 0.7 millimeter (0.03 inch) in thickness. An HF reader antenna creates a well-defined read field, so if something were to move outside of the reader antenna’s coverage area, its tag would no longer be interrogated. Thus, you would know that the object was outside the read zone.
—Mark Roberti, Founder and Editor, RFID Journal
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