Terahertz SAR Imaging Using a Fast-Sweeping Optoelectronic FMCW System with High-Gain Photoconductive Antennas

We present a synthetic aperture radar (SAR) imaging approach in the terahertz (THz) range using a fast-sweeping optoelectronic frequency-modulated continuous wave (FMCW) system and high-gain photoconductive antennas. Performance was benchmarked against commercially available antennas. Spectral analysis reveals that the high-gain antennas maintain a significantly broader bandwidth and a minimum signal-to-noise ratio (SNR) of 25 dB across the 1.5 THz scan range. Radargrams were generated and back-projected for image reconstruction. The high-gain antenna configuration produced images with sharper contours and fewer artifacts. Resolution analysis based on a cross-sectional cut yielded a 3 dB width of 194 µm for the high-gain antennas, compared to 360 µm for the standard configuration, demonstrating a substantial enhancement in spatial resolution.