A kind of period permanent magnetic circuit in ka-band klystron

A period permanent magnetic circuit in ka-band klystron is disclosed. The structure is composed of multiple independent magnetic rings clamping therebetween with pole pieces made of high permeability material. The arrangement method of the magnetic rings is to make same polarity in opposite alignment. The magnetic circuit is independent of high frequency circuit and the locations of magnetic rings and pole pieces are independent of the locations of individual chambers in the high frequency circuit. Good electron focusing effect can be achieved for micro-scale components with milli-wave frequency, especially for those very thin chamber wall structure with dual gap distribution function chamber.