Topic Gunn - oscillator
 
  Millimeter wave technology used to be the technological limit of what is physically possible. At that time (around 1980) there were no amplifier modules in the high Ghz range (up to 140 Ghz). The only way to generate small signals based on semiconductors were gallium arsenide gunn elements and impatt diodes. Everything was milled from solid material in solid waveguide technology (with waveguide widths of a few millimeters) and so the first car collision avoidance radar, millimeter wave radio for high-speed trains (Transrapid !!!) and others technology gadgets were developed.

In this (from today's point of view) golden "stone age technology" (all parts were silvered or gold-plated due to the lower electrical losses), solid electromechanical technology and theory were operated at the forefront.
Presentation An eight page report within the "Wissenschaftliche Berichte AEG-Telefunken" with 0.7 MB
Data please have a look to the report.
Notes ... those were the days ... there was no internet, documents were cast in paper.
September 1979