The microwave magnetron and its derivatives

The history of the microwave magnetron and the various crossed-field devices that have evolved from it is reveiwed from the time of the invention of the multicavity magnetron during World War II to the present time from the viewpoint of one who has been continuously involved as an observer and contributor. Special attention is given to the contributions of many individuals that led to the maturization of the microwave magnetron as a highly-efficient manufacturable high-power device and then its conversion into a broadband amplifier. An attempt is made to better comprehend the basic behavior and future potential of the crossed-field device based upon historical observations, recently introduced new crossed-field devices, and recently introduced new ways to apply conventional magnetrons to new microwave systems.