| 摘要 |
PURPOSE:To permit reduction in area of a matching circuit pattern thereby to allow a microwave amplifier to be more compact, by a method wherein an electrode is provided on the lower surface of a non-conductive substrate, and a conductive film is partially provided on the upper surface thereof so as to connect with the electrode, and moreover, a dielectric film and a microstrip line are piled on the conductive film. CONSTITUTION:An electrode 52 is formed on the lower surface of a dielectric substrate 51, and strip-like metal films 54 are formed on some parts of the upper surface thereof, each of which films 54 is connected at both ends thereof to the electrode 52 through metal films 53 on side surfaces of the substrate, and are covered with a dielectric film 55, on which a microstrip line 56 is formed. If the thickness HD of the film 55 is made sufficiently smaller than the thickness H of the substrate 51, the characteristic impedance ZL of the low impedance part is determined by WL/HD, where WL is the line width of the film 56, since the films 54 and the electrode 52 have the same potential. Because HD is small, if WL is made small, ZL can be made sufficiently small, so that it is possible to reduce the line length lL while obtaining a necessary capacity C. In other words, if strip-like metal films 61 are provided on a substrate 13 as predetermined, then, it is possible to reduce the pattern area of the low impedance part. Accordingly, the matching circuit substrates 13, 14 reduce in size to allow the microwave amplifier to be more compact. |
