In the magnetron, an upper end hat 122 A is used as a composing element of a cathode structure member 12 A and includes a portion 122 Aa which is in contact with one end portion 121 a of a filament coil 121 . The thickness of the portion 122 Aa is reduced, whereby the portion 122 Aa is held not in contact with a center lead 124 . Owing to this, heat generated in the filament coil 121 can travel to the upper end hat 122 A without traveling directly to the center lead 124 . Therefore, even when the quantity of input power is reduced to such a degree as to be able to reduce noise, or even when the electron radiation area of the filament coil 121 is reduced, the getter effect can be displayed fully. As a result of this, noise reduction and cost reduction can be realized at the same time.
1. A magnetron, comprising:
an anode barrel member having more than one vane projected toward the center axis direction thereof; and
a cathode structure member disposed on the center axis of the anode barrel member and forming an action space between the anode vanes and itself,
wherein the cathode structure member includes a filament coil, upper and lower end hats respectively for supporting the two end portions of the filament coil, a center lead having a leading end portion fixed to the upper end hat and penetrating through the lower end hat while not in contact with the filament coil, and a getter disposed on the top surface of the upper end hat,
wherein the portion of the upper end hat in contact with one end portion of the filament coil at a radial outside of the upper end hat is held not in contact with the center lead.
2. The magnetron as set forth in claim 1 , wherein the thickness of the portion of the upper end hat in contact with one end portion of the filament coil is formed small.
3. A microwave using apparatus, comprising a magnetron as set forth in claim 1 .