Diffraction From Metallic Objects in Radar Imaging—Theory, Simulation, and Experimental Verification

Abstract

The paper describes the modelling of diffraction effects in radar imaging scans at and near sharp-edged metallic objects as the aperture dimension is close to the dimension of the object to be scanned. We evaluate the Fresnel-Kirchhoff integral within the process of radar imaging for an $\mathbf {1}$D synthetic aperture radar. The resulting compact imaging model describes the diffraction effects in a single convolution-based formula. This is the basis for the simulative analysis in which the derived model is compared to a numerical radar imaging model. Further, we test our derived diffraction model experimentally. It confirms the developed theory and opens up additional areas of application for diffraction effect impacted radar imaging. This might be: high precision cross-range measurement with micrometer accuracy; highly precise surface reconstruction unveiling surface uncertainties in the low double-digit micrometer range; and model-based radar image enhancement.

Keywords

• Diffraction
• millimeter wave radar
• radar imaging
• radar measurements
• radar theory
• synthetic aperture radar (SAR)