| 摘要 |
PURPOSE:To suppress only an unnecessary wave without any influence on a basic wave by connecting a subordinate waveguide having cutting-off characteristics at an operation frequency successively to the short circuit surface is a main oaveguide for the operation frequency and terminating the other end surface in a matched state by a microwave absorber. CONSTITUTION:To the center part of the connection surface 411 of the main waveguide 41 having width (a) and height (b), the subordinate waveguide 41a having width (a') and height (b') (a'<a and b'<b) is a connected successively, and the subordinate waveguide 41a is terminated nearly in a matched state by the microwave absorber 46. A microwave semiconductor element 43 is loaded by a loading pot 44 at distance l1 from the equivalent short circuit surface 42 of the main waveguide 41 for the basic wave close to the connection surface 411 between both waveguides. When the basic wave operation frequency is f0 and the width (a') is equal to c/2a'<f0 (c: velocity of light), the subordinate waveguide 41a has cutting-off characteristics at the frequency f0 and the equivalent short circuit surface for the operation frequency is DELTAl close to the subordinate waveguide side from the connection surface 411. An unnecessary wave in a frequency area f>c/2a' is suppressed by the absorber 42. |
