A Delta-Sigma modulator-based heterodyne FMCW radar for short-range applications
Sprache des Titels:
We present a heterodyne frequency-modulated
continuous-wave (FMCW) radar, applicable in short-range applications.
Owing to a modulation of the transmit (TX) signal, the intermediate
frequency (IF) signal can be shifted away from zero frequency to reduce
the influence of dc-offsets and low-frequency disturbances like, e.g.
flicker noise existing in components like mixers, amplifiers and
analog-to-digital converters. The presented system is based on E-band
transceivers realized in SiGe technology, which are fully integrated
with antennas in a plastic package. A sinusoidal modulation of the TX
signal is realized by a binary phase-shift keying modulator, which is
controlled by a Delta?Sigma sequence. The choice of a sinusoidal
modulation allows to reuse signal processing blocks which are typically
available in FMCW radars. Measurements show that the achievable
signal-to-noise ratio is comparable to a homodyne realization since the
Delta?Sigma noise can be filtered in the IF stage. Experiments with a
bandwidth of 8 GHz demonstrate measurements down to 12 cm with standard
deviations of the measured ranges lower than 60 mm. Compared to a
homodyne realization the blocking distance could be reduced by
approximately 40 mm.
Sprache der Kurzfassung:
International Journal of Microwave and Wireless Technologies