A Heterodyne 77-GHz FMCW Radar with Offset PLL Frequency Stabilization
Sprache des Titels:
Digest to the IEEE Topical Conference on Wireless Sensor and Sensor Networks
This contribution describes the realization of a
heterodyne frequency-modulated continuous-wave (FMCW)
radar system operating in the frequency band from 76 GHz
to 77 GHz. To implement the heterodyne principle two
voltage controlled oscillators (VCOs) are operated in order to
produce frequency ramp signals with a fixed frequency offset.
This allows to mitigate effects occurring in homodyne systems
like, e.g., DC-offsets or low-frequency noise components. To
avoid large divider values in the control loop the presented
system is based on an offset phase-locked-loop configuration.
In the presented implementation the same downconverter is
used to implement the offset-loop for both VCOs, which has
the positive effect that errors and noise influences in the
downconversion process?at least partly?cancel out in the
final FMCW output signal.