User's Guide

ScanBrick® W User Manual
Doc: ARE-016631
Issue: 7.2
Date: Sept 2022
6
1.5. Radar Summary
1.5.1. Introduction to ScanBrick® W Radar
The ScanBrick® W system is a FMCW MIMO radar which transmit a frequency modulated signal
continuously in order to measure range as well as angle and velocity. This differs from traditional
pulsed-radar systems, which transmit short pulses periodically.
FMCW radars uses short (millimeter) wavelength signals, which enables detection of objects with
sub-millimeter accuracy. It can also penetrate materials like plastic, drywall, and clothing while
maintaining its high level of performance despite harsh environmental conditions such as rain, fog,
dust and snow. The size of system components such as the antennas required to process mmWave
signals is small. An mmWave system operating at 77–81 GHz (with a corresponding wavelength of
about 4 mm), will have the ability to detect movements that are as small as a fraction of a millimeter.
An FMCW radar system transmits a chirp signal and captures the signals reflected by objects in its
path. A chirp is a sinusoid whose frequency increases linearly with time as shown in the frequency
vs time plot. A chirp is characterized by a start frequency fc, bandwidth (B), and duration (Tc). Slope
of the chirp defines the rate at which the chirp ramps up. In the figure, chirp is sweeping a bandwidth
of 4GHz in 40μs which corresponds to a slope of 100MHz/μs.
Figure 1: Chirp signal, with amplitude as a function of time
Figure 2: Chirp signal, with frequency as a function of time