Passive chip-less millimeter wave Radio Frequency Identification

This article describe a passive, chip-less millimeter wave radio frequency identification (RFID) technology that uses an array of microscopic resonant elements implanted into the paper, cardboard, and plastic substrates typically used for an optical label, such as a barcode. When illuminated with RF energy, the resonant array provides a ldquoRF Fingerprintrdquo based on parameters including density, thickness, and orientation of the embedded resonant elements. When the reflected RF energy is received by a tag reader placed at a distance, signal processing algorithms that detect and identify these ldquoRF Fingerprintsrdquo enable asset enrollment, identification and tracking. Because these RF enhanced substrates can be made compatible with existing printing facilities for optical barcode labels, both the Radio Frequency (RF) and optical identification capabilities can be integrated into a single chip-less tag entity. Background theory, system concepts, early experimental results, and applications of this automatic identification technology (AIT) are discussed.