Sub-THz systems for industrial inspection applications

Based on the setup employing a commercial vector network analyser equipped with a lens system, the feasibility for materials scanning is explored. As a result, a great potential for quality checking with microwaves is discovered. One of the application fields is the food industry. In particular, the use of millimeter wave systems for the detection of foreign objects and quality control is evaluated. The employment of screening systems is also of particular interest in the plastics industry. In the thesis it is proven that microwave imagers are well suited to the quality assessment of plastic welds and polymers. Typical problems appearing during the manufacturing of plastics including delaminations or the presence of inclusions can be detected. For plastics containing additives, a particle distribution map can be obtained. Since the millimeter waves are attenuated by water, another application of this part of the electromagnetic spectrum is the control of rehydration process in plants. Finally, the employment of microwave systems for security scanning is presented, however it is limited to the recognition of relatively high volume items.