Free-Space and Concealed Target Detection Using Nonlinear FMCW-Based Radar

Nonlinear detection is a technique that detects nonlinear interactions, such as harmonics and intermodulation, caused by semiconductor junctions, enabling the remote detection of nonlinear objects, such as small electronic devices with small radar cross-sections. The characteristics of such nonlinear radars enable the effective detection of targets equipped with small electronic devices in camouflaged and concealed environments, particularly in security and military applications. Therefore, this study constructs a nonlinear radar system utilizing FMCW to effectively detect the nonlinear response of small electronic devices at long distances. Using the constructed system, four small electronic devices, and manufactured nonlinear targets, successful detection was confirmed at a line-of-sight condition of 10 m, and even at a nonline-of-sight condition of 6 m.