To read a 13.56 MHz tag, I need a quarter-wavelength antenna of 5.5 meters (18.feet). Can this be wound in a coil with the tag still readable, or does it need to remain straight?
A passive high-frequency (HF) tag must be wound in a coil. HF tags communicate with a reader via inductive coupling. The coiled tag antenna and the coiled reader antenna form an electromagnetic field. Changes in this field allow the tag and reader to exchange information.
—Mark Roberti, Founder and Editor, RFID Journal
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