Terahertz Non-destructive Testing of the Mica Insulation of Power Generator Bars in FMCW Measurements with a Dielectric Waveguide Antenna

In recent years, many terahertz and millimeter wave technologies have evolved from a scientific background into very specific industrial contexts. One field of such “real-world” applications is non-destructive testing (NDT) for sub-surface defects in quality control and product maintenance environments. In this contribution, we present a terahertz system combining an all-electronic 100 GHz transceiver with a dielectric waveguide antenna for sub-wavelength NDT imaging. We employ frequency-modulated continuous wave (FMCW) measurements to record depth-resolved, volumetric terahertz images. This combined system concept is demonstrated at the example of NDT of the mica insulation of power generator bars with only limited available measurement space between the bars and where an early detection of defects and cracks in the insulation can be crucial.