Multilayer structural diagnosis with quasi-3D microwave imaging using ultrawideband radio frequency noiselet waveforms

Microwave radar imaging is increasingly being used in infrastructure monitoring applications due to its low cost, rapid measurement time, non-contact characteristics, and ability to penetrate nonmetallic media. An appropriate waveform design must be designed to obtain accurate information on the targets observed or the features being probed. Ultrawideband (UWB) radio frequency (RF) noiselets are excellent candidate waveforms in view of their multiresolution and interference rejection features. In this paper, a waveform optimization approach for UWB noiselet waveforms is described to achieve high peak-to-sidelobe ratio (PSLR) to enhance imaging capabilities. Synthetic aperture radar (SAR) scanning for microwave imaging is introduced after analyzing the essential microwave approaches for the multilayered structure. Image reconstruction using SAR scanning is performed for various multilayered structures and quasi-3D images of these structures are presented for nondestructive testing and evaluation (NDT & E) applications.