The Rising Sun Magnetron

Abstract

A method for separating the π-mode from neighboring resonant modes in a multi-cavity magnetron without the use of ``straps'' is described. The new resonant circuit design known as the ``rising sun'' design utilizes two different resonator sizes arranged symmetrically around the cylindrical cathode-anode space, with resonators alternately larger and smaller. Some of the essential features of the mode spectrum and the electromagnetic field in the interaction space in this design are derived from a simple lumped-constant theory. The advantages of the rising sun over the strapped anode block become important in the short wave-length part of the microwave region, because of simpler construction and smaller radiofrequency losses. For very high power magnetrons the advantages of the rising sun structure apply to wave-length as long as 10 cm.