@inproceedings{SchoppHeuermannMarso2017,
  author    = {Schopp, Christoph and Heuermann, Holger and Marso, Michel},
  title     = {Multiphysical Study of an Atmospheric Microwave Argon Plasma Jet},
  series = {IEEE Transactions on Plasma Science},
  volume    = {45},
  booktitle = {IEEE Transactions on Plasma Science},
  number    = {6},
  publisher = {IEEE},
  issn      = {1939-9375},
  doi       = {10.1109/TPS.2017.2692735},
  pages     = {932 -- 937},
  year      = {2017},
  language  = {en}
}
@article{SchoppBritunVoracetal.2019,
  author    = {Schopp, Christoph and Britun, Nikolay and Vorac, Jan and Synek, Petr and Snyders, Rony and Heuermann, Holger},
  title     = {Thermal and Optical Study on the Frequency Dependence of an Atmospheric Microwave Argon Plasma Jet},
  series = {IEEE Transactions on Plasma Science},
  volume    = {47},
  journal   = {IEEE Transactions on Plasma Science},
  number    = {7},
  publisher = {IEEE},
  address   = {New York},
  issn      = {1939-9375},
  pages     = {3176 -- 3181},
  year      = {2019},
  language  = {en}
}
@article{SchoppRohrbachLangeretal.2024,
  author    = {Schopp, Christoph and Rohrbach, Felix and Langer, Luc and Heuermann, Holger},
  title     = {Detection of welding wire length by active S11 measurement},
  series = {IEEE Transactions on Plasma Science},
  journal   = {IEEE Transactions on Plasma Science},
  number    = {Early Access},
  publisher = {IEEE},
  issn      = {0093-3813 (Print)},
  doi       = {10.1109/TPS.2024.3356659},
  pages     = {1 -- 6},
  year      = {2024},
  abstract  = {A novel method to determine the extruded length of a metallic wire for a directed energy deposition (DED) process using a microwave (MW) plasma jet with a straight-through wire feed is presented. The method is based on the relative comparison of the measured frequency response obtained by the large-signal scattering parameter (Hot-S) technique. In the practical working range, repeatability of less than 6\% for a nonactive plasma and 9\% for the active plasma state is found. Measurements are conducted with a focus on a simple solution to decrease the processing time and reduce the integration time of the process into the existing hardware. It is shown that monitoring a single frequency for magnitude and phase changes is sufficient to achieve good accuracy. A combination of different measurement values to determine the length is possible. The applicability to different diameter of the same material is shown as well as a contact detection of the wire and metallic substrate.},
  language  = {en}
}