Free Electron Maser as a Frequency Agile Microwave Source

Most microwave sources have a very limited operating frequency range without the use of mechanical tuning. This is because they tend to be slow wave devices with an internal structure which prevents wide frequency variation. A waveguide free electron maser is a fast wave device which does not suffer from this limitation. Selection from a wide range of operating frequencies can be made by simply adjusting the operating voltage. This paper reports the development of a reasonably low cost free electron maser (FEM) as a source for applications requiring a frequency agile microwave power source.