Millimeter Wave and Terahertz Synthetic Aperture Radar for Locating Metallic Scatterers Embedded in Scattering Media

TL;DR

This paper demonstrates the use of millimeter wave and terahertz synthetic aperture radar to locate metallic scatterers embedded in scattering media, achieving high resolution imaging and discussing methods to improve signal quality.

Contribution

It introduces a dual-band SAR system operating at W-band and THz frequencies for locating metallic scatterers in scattering media, with novel scene reconstruction techniques.

Findings

High resolution at W-band (4.3 mm range, 2 mm cross-range)

Enhanced spatial resolution at THz band (0.86 mm)

Effective localization in semi-transparent media, limited in opaque media

Abstract

A rail-mounted synthetic aperture radar has been constructed to operate at W-band (75 - 110 GHz) and a THz band (325 - 500 GHz) in order to ascertain its ability to locate isolated small, visually obscured metallic scatterers embedded in highly scattering dielectric hosts that are either semi-transparent or opaque. A top view 2D algorithm was used to reconstruct scenes from the acquired data, locating metallic scatterers at W-band with high range and cross-range resolution of 4.3 and 2 mm, respectively, and with improved range resolution of 0.86 mm at the THz band. Millimeter-sized metallic scatterers were easily located when embedded in semi-transparent, highly scattering target hosts of Styrofoam and waxy packing foam but were more difficult to locate when embedded in relatively opaque, highly scattering Celotex panels. Although the THz band provided the expected greater spatial resolution, it required the target to be moved closer to the rail and had a more limited field of view that prevented some targets from being identified. Techniques for improving the signal to noise ratio are discussed. This work establishes a path for developing techniques to render a complete 3D reconstruction of a scene.