To provide a highly reliable product by suppressing the unnecessary radiation and leakage of the microwave energy of a fundamental wave to a power supply side from a magnetron input side which arise from a product variation, and a preferential structure for productivity.
A metal plate is formed into a hat shape projecting to an interaction space side, a half of its bottom is airtightly brazed to a metallized part of a stem for deriving a cathode terminal, the remaining half of the bottom forms a shape having no bottom so that it is not brought into contact with a lead wire which is not electrically and directly connected to the bottom side, its hat-shaped first and second metal plates 42, 43 the halves of which have no bottom are formed so that a bottomless part at the right side is reversed to that at the left side, and the metal plates are disposed so as to cover the same axis with their drawn parts having shapes with different inner diameters.
HANDA TAKANORI
Hiroki Naito
Daisuke Nagano