Current European Developments in Microwave Tubes

The paper gives a brief description of the present state of the European microwave tube art. Developments on lines which differ from those common in the U.S.A. are stressed. After a few specialized tube types have been described, current research is surveyed, covering devices using electron beams in high vacuum, electron beam parametric amplifiers and microwave amplification in plasmas. Purely theoretical material has been omitted except where it is vital to the understanding of any device.