ABSTRACT
This chapter reveals some of the most relevant capabilities of ultrawideband (UWB) radar sensors applied to nondestructive testing (NDT). It will show the value, strengths, and limitations of UWB NDT technology imposed by technology or physical limits. The value of UWB radar sensors in the extremely high frequency (EHF) microwave band, that is, from 10 gigahertz (GHz) to 300 GHz [1], still needs practical demonstrations for the
CONTENTS
6.1 Introduction to Extremely High-Frequency Microwave Ultrawideband Radars for the Nondestructive Testing of Aeronautical Structures ........................................ 237
6.2 UWB Radar NDT Applications........................................................................................ 240 6.2.1 A Survey of Existing NDT Techniques ............................................................... 240 6.2.2 NDT with FMCW UWB Radar Sensors ............................................................. 240
6.2.2.1 The Quasi-Optical FMCW UWB Radar for NDT ............................... 244 6.2.2.2 UWB NDT Sensors Using Synthetic Aperture Radar ....................... 244
6.2.3 Discussion and Conclusions about SAR Algorithms for UWB Radar NDT ....247 6.3 Materials Testing and Comparison of UWB Radar NDT Results .............................. 248
6.3.1 Description of the Tested Composite Materials ................................................ 248 6.3.2 Results of Focused FMCW UWB Radar Tests on Selected Samples .............. 248 6.3.3 Results of Synthetic Aperture FMCW UWB Radar Imaging of Selected
Samples ....................................................................................................................254 6.4 Semiautomatic Image Processing for EHF UWB NDT ................................................256
