Integrated Active Pulsed Reflector for FMCW Radar Localization

This paper presents an integrated active pulsed reflector (APR) functioning as a backscatterer in a power efficient local positioning system using a frequency modulated continuous wave (FMCW) radar in the ISM band at 5.8 GHz. The APR is designed as a switchable, tunable oscillator and is integrated in a 0.18-mum CMOS technology. The operating frequency of the APR can be tuned from 5.45 to 6.69 GHz, the output power is between 2.17 and 6.11 dBm and the matching is better than -9 dB over the complete tuning range. The active reflector including a low-frequency oscillator for modulation draws 46.2 mA from a 3.3 V power supply. The operation principle was verified and a measurement accuracy of 4.9 cm over a measurement range of 1.5 to 7.5 m was achieved neglecting multipath effects.