GENERATION OF PICOSECOND PULSES AT MILLIMETER WAVELENGTHS

We report here on an experiment in which picosecond electron pulses, p roduced by a compact radiation frequency (rf) electron gun, were used to excite a rectangular waveguide, generating 5 ps pulses of radiation with a bandwidth of similar to 200 GHz. The interaction of the electr on pulses with the waveguide can be modeled quite simply by performing a harmonic expansion of the pulse train produced by the electron gun and employing Poynting's theorem to compute the power coupled into the modes of the waveguide by each harmonic. The resulting model for the distribution of spectral power yields good agreement with the observed spectrum. (C) 1995 American Institute of Physics.