Concept of a high power W-band maser based on a two-dimensional structure

High power millimetre-wave sources operating in W-band (75 GHz-110 GHz) frequency range which are capable of generating coherent radiation at high power up to a few 10s of MWs are important for a number of applications. In order to achieve coherent radiation at high power, the use of an oversized electron beam is required. The use of a 2D periodic lattice was suggested to obtain 2D distributed feedback resulting in synchronization of the different parts of the oversized active medium. This will allow problems associated with high electromagnetic power density such as electric field breakdown in the interaction space to be overcome. Various coherent radiation sources based on a 2D periodic lattice such as Smith Purcell, free electron, cyclotron resonance and Cherenkov masers have been studied to obtain a better understanding of their suitability for the generation of single mode, single frequency, high power radiation.