@article{HoltrupSadeghfamHeuermannetal.2014,
  author    = {Holtrup, S. and Sadeghfam, Arash and Heuermann, Holger and Awakowicz, P.},
  title     = {Characterization and optimization technique for microwave-driven high-intensity discharge lamps using hot S-parameters},
  series = {IEEE transactions on microwave theories and techniques},
  volume    = {62},
  journal   = {IEEE transactions on microwave theories and techniques},
  number    = {10},
  publisher = {IEEE},
  address   = {New York},
  issn      = {0018-9480},
  doi       = {10.1109/TMTT.2014.2342652},
  pages     = {2471 -- 2480},
  year      = {2014},
  abstract  = {High-intensity discharge lamps can be driven by radio-frequency signals in the ISM frequency band at 2.45 GHz, using a matching network to transform the impedance of the plasma to the source impedance. To achieve an optimal operating condition, a good characterization of the lamp in terms of radio frequency equivalent circuits under operating conditions is necessary, enabling the design of an efficient matching network. This paper presents the characterization technique for such lamps and presents the design of the required matching network. For the characterization, a high-intensity discharge lamp was driven by a monofrequent large signal at 2.45 GHz, whereas a frequency sweep over 300 MHz was performed across this signal to measure so-called small-signal hot S-parameters using a vector network analyzer. These parameters are then used as an equivalent load in a circuit simulator to design an appropriate matching network. Using the measured data as a black-box model in the simulation results in a quick and efficient method to simulate and design efficient matching networks in spite of the complex plasma behavior. Furthermore, photometric analysis of high-intensity discharge lamps are carried out, comparing microwave operation to conventional operation.},
  language  = {en}
}
@article{HeuermannPetersSchmitzetal.2005,
  author    = {Heuermann, Holger and Peters, N. and Schmitz, T. and Sadeghfam, Arash},
  title     = {Concept of Balanced Antennas with Load-Invariant Base Impedance Using a Two Element LC-Coupler. Peters, N., Schmitz, Th., Sadeghfam, A., Heuermann, H.},
  series = {Proceedings of the European microwave association : journal of the European microwave association},
  journal   = {Proceedings of the European microwave association : journal of the European microwave association},
  publisher = {PLUS},
  address   = {Pisa},
  pages     = {117 -- 122},
  year      = {2005},
  language  = {en}
}
@inproceedings{StephanHeuermannPrantner2016,
  author    = {Stephan, Achim and Heuermann, Holger and Prantner, Michael},
  title     = {Cutting human tissue with novel atmospheric-pressure microwave plasma jet},
  series = {46th European Microwave Conference (EuMC)},
  booktitle = {46th European Microwave Conference (EuMC)},
  publisher = {IEEE},
  isbn      = {978-2-87487-043-9},
  doi       = {10.1109/EuMC.2016.7824490},
  pages     = {902 -- 905},
  year      = {2016},
  language  = {en}
}
@inproceedings{ElgamalHeuermann2020,
  author    = {Elgamal, Abdelrahman and Heuermann, Holger},
  title     = {Design and Development of a Hot S-Parameter Measurement System for Plasma and Magnetron Applications},
  series = {2020 German Microwave Conference (GeMiC), Cottbus, Germany, 2020},
  booktitle = {2020 German Microwave Conference (GeMiC), Cottbus, Germany, 2020},
  isbn      = {978-3-9820397-1-8},
  pages     = {124 -- 127},
  year      = {2020},
  language  = {en}
}
@inproceedings{SadeghfamSadeghiAhangarElgamaletal.2019,
  author    = {Sadeghfam, Arash and Sadeghi-Ahangar, A. and Elgamal, Abdelrahman and Heuermann, Holger},
  title     = {Design and Development of a Novel Self-Igniting Microwave Plasma Jet for Industrial Applications},
  series = {IEEE MTT-S International Microwave Symposium Digest},
  booktitle = {IEEE MTT-S International Microwave Symposium Digest},
  isbn      = {978-172811309-8},
  pages     = {63 -- 66},
  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}
}
@article{Heuermann2008,
  author    = {Heuermann, Holger},
  title     = {Dual mode radio: A new tranceiver architecture for UWB and 60 GHz-applications},
  series = {European Conference on Wireless Technology, 2008. EuWiT 2008.},
  journal   = {European Conference on Wireless Technology, 2008. EuWiT 2008.},
  isbn      = {978-2-87487-008-8},
  pages     = {147 -- 150},
  year      = {2008},
  language  = {en}
}
@article{HeuermannSadeghfam2008,
  author    = {Heuermann, Holger and Sadeghfam, Arash},
  title     = {Electrically tunable bandpass filter with integrated carrier suppression for UHF RFID systems / Sadeghfam, Arash ; Heuermann, Holger},
  series = {European Microwave Conference, 2008, EuMC 2008, 38th},
  journal   = {European Microwave Conference, 2008, EuMC 2008, 38th},
  isbn      = {978-2-87487-006-4},
  pages     = {1727 -- 1730},
  year      = {2008},
  language  = {en}
}
@article{HeuermannSadeghfam2008,
  author    = {Heuermann, Holger and Sadeghfam, Arash},
  title     = {Electrically tunable bandpass filter with integrated carrier suppression for UHF RFID systems / Sadeghfam, Arash ; Heuermann, Holger},
  series = {European Conference on Wireless Technology, 2008. EuWiT 2008.},
  journal   = {European Conference on Wireless Technology, 2008. EuWiT 2008.},
  isbn      = {978-2-87487-008-8},
  pages     = {306 -- 309},
  year      = {2008},
  language  = {en}
}
@inproceedings{SchoppHeuermann2013,
  author    = {Schopp, Christoph and Heuermann, Holger},
  title     = {Electrodeless low pressure lamp with bi-static matching at 2.45 GHz},
  series = {2013 European Microwave Conference (EuMC) , Nuremberg},
  booktitle = {2013 European Microwave Conference (EuMC) , Nuremberg},
  publisher = {IEEE},
  address   = {Piscataway, NJ},
  isbn      = {978-1-4799-0264-4},
  pages     = {881 -- 884},
  year      = {2013},
  language  = {en}
}