Developments in marine radar magnetrons

Magnetrons for civil marine radar applications have been manufactured on the e2v Chelmsford site since 1947. The earliest production was of the original S band wartime designs developed by the Radiation Laboratory at MIT but it was not long before engineers at the then English Electric Valve Company began making improvements. This paper traces the development of magnetrons for marine radar from the first glass envelope "Gen 1" devices to the current state of the art in 4^th generation magnetrons. Each generation of magnetrons introduced significant design innovations and the designers also took advantage of technological developments in both materials and production techniques. The key changes are described and illustrated together with some of the technological improvements that have resulted in today\´s highly reliable devices. These latest devices embody novel techniques for internal suppression of unwanted oscillatory modes and also use novel processing techniques to achieve unprecedented levels of performance and reliability.