Open electrodynamic systems in relativistic diffraction electronics

We examine the possibility of using an open diaphragmed transmission line as an electrodynamic system of relativistic diffraction electronics. We investigate theoretically and experimentally the amplitude and phase characteristics of the line used as a homogeneous and inhomogeneous wave guide. The theoretical investigation was done by numerical solution of nonlinear integral equations by iteration methods. We describe a method of measuring the phase shift of a wave on its passage through the diaphragms. The experimental research was done in the millimeter - wave - length region. Good agreement was obtained between the theoretical and experimental results. The theoretically calculated efficiency for the diffraction radiation of a relativistic polyhelicoid current in the investigated wave guide reaches 25 to 30%.