Frequency adaptable maser source

In devices such as magnetrons, gyrotrons, etc., a magnetic field is used to alter the velocity. However, there are other mechanisms for RF emission. An electron beam grazing a surface waveguide, traveling through a diffraction grating, or a dispersive medium can also emit radiation via the Cherenkov and Smith-Purcell mechanisms. An added flexibility is that the emission frequency can be controlled by the geometry grating or the material properties of the dispersive medium. A novel adaptable RF Maser source using the Smith-Purcell effect that is tunable up to 10 GHz has been designed. A detailed simulation of the performance was done using the open source software package, MEEP from MIT/LL, incorporating an axially slotted rectangular waveguide.