Cerenkov Radiation in Dielectric-Loaded Waveguides.

The use of Cerenkov radiation as a source of high frequency, high power microwave radiation is dealt with in detail in this paper. Using the Cerenkov interaction, produced when a relativistic electron beam is passed down the center of a dielectric-lined waveguide, we have been successful in producing microwave radiation at frequencies in excess of 150 GHz and power levels of about 1 W. In addition we have observed microwave radiation with approximately 1 kW of peak power at frequencies between 20 GHz and 35 GHz. We present these results and a theoretical model which serves to explain many of the experimental observations and the basic scaling of such a Cerenkov microwave generator. By proper manipulation of the various parameters of the experiment we show theoretically how a Cerenkov generator might be scaled in such a way as to be a viable source of high power, submillimeter radiation. Finally, we discuss specific methods which may be applied to the present experimental efforts in order to investigate the various ways in which higher output frequencies and powers may be obtained.