T-Ray Imaging

The millimeter wave frequency range up to the lower terahertz frequencies (T-ray imaging) offers the opportunity to look through many materials, e.g. for non destructive test systems for quality control or the detection of non metallic and/or under cloth wearied weapons. Other fields of interest for this frequency range are medical applications, especially the detection of skin cancer. There, a major drawback is the high absorption of the radiation by polar molecules like water in this frequency range. Therefore, non-invasive in-vivo measurements are sensible in skin applications. The early detection of skin cancer is difficult, because it often emerges beneath the skin and therefore, most lesions are visible only in an advanced state. It is assumed that the T-ray/tissue interaction properties are different in benign and malign tissue, because, for example, the cell structure and the water consistent of skin pathologies are different.

We developed a synthesized sweep generator by Agilent (Agilent 83650B), which covers the frequency spectrum from 10 MHz through 50 GHz. To generate frequencies from 75 GHz up to 110 GHz a mmW source module (Agilent 83550B) is used. The source module consists of an internal amplifier and a six time frequency multipliers. For higher frequencies up to 260 GHz, several external frequency multipliers are used. An additional external amplifier driver stage in the frequency range from 28.33 GHz to 43.33 GHz with an output power of 300 mW compensates the conversion loss. The signals are detected with a spectrum analyzer (Rhode&Schwarz FSEK30) using an external mixer. In addition to the scalar measurement system a vector network analyzer (VNA) is available and measures frequencies and phase up to 110 GHz.

Scanner in reflection configuration at 260GHz. Experimental set-up at FGAN, Wachtberg

Former Project Members

  • Christian Krebs (RheinAhrCampus Remagen)
  • Dirk Nüßler (FGAN - Wachtberg)
  • Thorsten M. Buzug (University of Luebeck)


Fraunhofer-Institut für Hochfrequenzphysik und Radartechnik FHR, Professor. Dr. Joachim Ende


2007[ to top ]
  • Krebs, C., Buzug, T. and Nüßler, D.: An Imaging System in the Sub Millimeter Area, 69–74, 2007, DOI: 10.1007/978-3-540-68764-1_11.
2006[ to top ]
  • Krebs, C., Nüßler, D., Heinen, S. and Buzug, T. M.: Experimenteller Prototyp eines Gewebescanners im unteren Terahertz-Bereich, 2006.
  • Krebs, C., Nussler, D., Heinen, S., Zeru, D. and Buzug, T.: Material Scanner Using mmW-Radiation, 1453–1456, 2006, DOI: 10.1109/EUMC.2006.281331.
2005[ to top ]
  • Buzug, T. and Kohl-Bareis, M.: Medical Imaging in the [1012Hz - 1014Hz] Domain, 1728–1731, 2005, DOI: 10.1109/IEMBS.2005.1616778.
2004[ to top ]
  • Buzug, T. M., Holz, D., Kohl-Bareis, M. and Schmitz, G.: Frontiers in Medical Imaging, 37–42, 2004.