Confocal terahertz SAR imaging of hidden objects through rough-surface scattering

Area of Science:

• Applied Physics
• Electromagnetics
• Imaging Science

Background:

• Terahertz (THz) radar imaging offers deep penetration in non-conductive materials.
• Image quality in THz radar imaging is degraded by surface scattering, posing a significant challenge.
• Existing methods struggle to mitigate scattering effects effectively.

Purpose of the Study:

• To propose a novel confocal terahertz synthetic aperture radar (SAR) system.
• To address and alleviate image degradation caused by rough surface scattering.
• To enhance both image resolution and signal-to-noise ratio (SNR) in THz imaging.

Main Methods:

• A convex lens was integrated into a conventional SAR system to create a confocal configuration.
• The confocal setup localizes scattering effects within spatial sampling points.
• Temporal domain shifting was employed for correcting random phase aberrations induced by scattering.

Main Results:

• Experimental evaluations demonstrated significant improvements in image resolution.
• The proposed confocal THz SAR system showed enhanced signal-to-noise ratio (SNR).
• Performance was validated across various surface roughness conditions.

Conclusions:

• The confocal terahertz SAR effectively mitigates scattering issues in THz imaging.
• The method provides a substantial enhancement in both resolution and SNR compared to conventional approaches.
• This technique shows promise for applications requiring high-quality THz imaging of rough surfaces.