Abstract: A wide band device is provided for coupling between the delay line of a travelling wave tube and the external circuit transmitting the energy of the tube, comprising a coupling wave guide having a single ridge, connected on one side to the delay line and on the other being extended by one of the two ridges of the output guide, the section of the coupling guide increasing progressively, with constant impedance from the line to the output guide whereas this latter has an impedance transformer providing impedance matching between its standard guide part and the coupling guide.

Abstract: The present invention relates to a circular window for an ultra-high frequency waveguide. This window is constituted by a circular plate or wafer made from a dielectric material mounted in a waveguide section, connected on either side of a waveguide operating in a frequency band centered around the central frequency. The diameter of the circular plate is chosen so as to reject the ghost modes outside the frequency band. The length of the circular guide section is chosen so that the reactance of the assembly constituted by the plate and the circular guide is cancelled out for the central frequency. It also comprises a half-wave impedance transformer, whose height is chosen so as to bring about the matching in the operating frequency band. The window associated with rectangular waveguides is more particularly used with tubes for telecommunications.