The Teratron^™ is a novel patent pending  electron tube.  The Teratron^™ is a power
  amplifier capable of producing kilowatt level outputs between of megawatt signals to 100 GHz and 
  kilowatt  signals to 2 THz.  This tube operates  on an entirely new principle.  As is the case with all
  other Hudson Research tubes, it utilizes our proprietary cold cathode coupled with state of the art
  RF circuitry.  This tube supplants other microwave tubes such as Klystrons, Traveling Wave Tubes,
  Backward Wave Oscillators, Gyrotrons, Inductive Output Tubes and other similar tube types. The
  Teratron^™ is a highly efficient and compact design, a fraction of the size of competitive tubes.