Patent ID: 9000669
Filing Date: 2015-04-07
Classification: H01J

Abstract:
1. A magnetron comprising: an anode cylinder which has a cylindrical shape with both ends opened and which comprises a plurality of vanes radially provided on an inner wall surface thereof; a pair of pole pieces positioned in openings of the both ends of the anode cylinder; metal sleeves which are positioned outside the pair of pole pieces and configured to air-tightly seal the anode cylinder, and each of which comprises a cylinder part, a flange part continuous with the cylinder part, and a plurality of protrusions provided on a portion in which the cylinder part continues with the flange part; and a doughnut-shaped annular magnet placed on the flange part of each metal sleeve and spaced apart from the cylinder part of each metal sleeve; wherein the plurality of protrusions are arranged in a space between the cylinder part of each metal sleeve and the magnet and the flange part comprises an upper surface facing the magnet and a lower surface facing the pole pieces, wherein the protrusions are arranged at the junction of the cylinder part and the flange part of each metal sleeve and do not contact the magnet.