FMCW Sensors for Detecting Hidden Objects
B. Kapilevich, Stuart William Harmer, Nicholas John Bowring · 2014
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 R x and T x operations—monostatic configuration that is typical for a radar; and sensors with the separated antennae for both R x and T x 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.