1-D Frequency-Diverse Single-Shot Guided-Wave Imaging Using Surface-Wave Goubau Line

This article presents a 1-D frequency-diverse guided-wave imaging technique based on a surface-wave Goubau line. It employs frequency diversity to capture spatial information of the scatterers with an almost real-time speed, which is much faster than mechanical scanning or electronic scanning approaches. The surface-wave Goubau line is used because it provides more independent measurement modes than conventional transverse electromagnetic (TEM) transmission lines. Compressed sensing algorithms are employed to recover the spatial distributions when some sparse metal scatterers are placed above the line. The proposed technique is validated by four numerical examples and two experimental validations, where both narrow scatterers and wide scatterers are considered. It shows that the proposed technique is able to reconstruct scatterer position within an error of 1 mm, about 1/30 space wavelength at the center frequency 10 GHz. It is also able to identify two close scatterers until their distance reduces to 1 mm. This guided-wave technique, although applicable to very near-field detection only, can find broad applications in localization, field measurement, and fault detection.