Precise ranging and simultaneous high speed data transfer using mm-wave regenerative active backscatter tags

For precise ranging in dense indoor RFID applications, a large absolute bandwidth is required for effective multipath suppression. Since the bandwidth of UHF systems is severely restricted, we propose mm-wave tags combined with high volume data storage and high speed data transfer (≫10 MBit/s) as an attractive alternative - in short range (1-10 m) augmented reality and multimedia applications, for example. A regenerative active backscatter tag based on a pulsed injection-locked oscillator is suggested in order to achieve a sufficiently high reader SNR for high bandwidth communication. This paper demonstrates that a 34.3-34.8 GHz frequency modulated continuous wave (FMCW) RFID ranging approach can be integrated seamlessly with simultaneous data transmission from the modulated active backscatter tag to the reader at 37.5 MBit/s. Mutual distortions between FMCW ranging and data transmission are prevented by line encoding and quadrature mixing.