Radar Measurements with Micrometer Accuracy and Nanometer Stability Using an Ultra-Wideband 80 GHz Radar System

In this paper, a high precision 80 GHz radar distance measurement system is presented. It is based on an ultra-wideband SiGe monostatic transceiver chip, which enables a bandwidth of 25.6 GHz around a center frequency of 80 GHz (i.e. 32%). All components besides the silicon radar chip are off-the-shelf electronics, which makes the sensor well-suited for low-cost industrial measurement applications. First, the measurement stability of the system is characterized. An excellent phase noise of -88 dBc/Hz (10 kHz offset from an 80 GHz carrier) was measured. Furthermore the stability of distance measurements inside a waveguide, are presented, which results in a standard deviation of the targets' phase of 0.008 degree, which corresponds to a distance jitter of 41 nm. Finally a measurement setup with a high precision linear motor on a low vibration table is used for distance measurements. A distance error below 4 micrometer was achieved and confirmed by three different measurement runs.