ABSTRACT
Frequency-modulated continuous wave (FMCW) signals are widely used in radar technologies currently deployed for wide area surveillance, site security, anti-collision transport systems and level control sensors, including altimetres and imaging systems. FMCW relies on the difference between transmitted and received frequency of a frequency-swept waveform. FMCW sensors can be classified into two categories: sensors with the single antenna for both Rx and Tx operations—monostatic configuration that is typical for a radar; and sensors with the separated antennae for both Rx and Tx operations—bistatic configuration. The transmitting and receiving modes in the FMCW sensors operate simultaneously, and an increase of power automatically reduces the overall system performance due to destructive leakage. Millimetre-wave imaging systems operating in FMCW mode have been intensively developed for concealed weapon detection in various homeland security scenarios. Non-imaging sensors operating with the FMCW mode determine the location of a hidden object with high accuracy.
