Magnetron for microwave ovens

摘要

A magnetron includes upper and lower shields (700,800) to cover a top and bottom of a filament (106), respectively. Upper and lower pole pieces (117,118) are disposed to induce magnetic flux into the activating space. The upper shield (700) and/or the lower shield (800) have a diameter ranging from 6.95 mm to 7.10 mm. The upper shield and the lower shield (700,800) are each geometrically structured to change electric and magnetic fields in the activating space, thereby preventing thermions emitted by the filament from escaping the activating space.