| 摘要 |
PURPOSE:To dispense with the mechanical support of an antenna and to prevent the contamination due to a metal by a method wherein an antenna of a struc ture, wherein an antenna pattern is patterned on the outer wall of a vacuum container constituted of an insulator, is used as a microwave feeding means. CONSTITUTION:An antenna pattern 41 is patterned on the outer wall of a dis charge container 4. The pattern 41 is formed into a slot type, is a Lisitano coil and is one, wherein slits of a length of (l) and a width of several mm are cut. If the length (l) of the slits is chosen in 1/2 of the wavelength of a microwave to be fed, a standing wave is generated. The container 4 is constitut ed of a microwave penetrating insulator of quartz glass, alumina or the like, such a metal as copper or silver is deposited on its outer wall and the metal is etched in a pattern type to form the antenna pattern 41. The thickness of the metal of the pattern has only to be larger sufficiently than the depth of a skin which is generated by a skin effect. The antenna pattern can be either the slot type or a helical type and the direction of an internal electric field to be generated is formed into the form of a concentric circle and intersects orthogonally with a magnetic field to be generated by an air-core coil 5.
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