| 摘要 |
PURPOSE:To improve the leading characteristic, to miniaturize the shape, to reduce the insertion loss and to facilitate manufacture and adjustment by applying indirect coupling to resonators apart by two or its integer multiple of number of resonators in a lambda/4 coaxial dielectric resonator by means of an indirect coupling circuit having a specific length coupled with a main circuit due to capacitive coupling. CONSTITUTION:The indirect coupling circuit 8 is formed that a transmission line such as a coaxial cable and a proper phase delay line are connected in series, coupling capacitive elements 91, 92 are fitted to both ends and the total length is formed as lambda/2 or its odd number of multiple including the length of the elements 91, 92. A phase difference of -180 deg. is caused between an electric phase +90 deg. of a signal at the attenuating region from a point P2 reaching a point P5 through the main circuit and an electric phase +90 deg. of a signal in the attenuation region from the point P2 reaching the point P5 through the indirect coupling circuit 8. Then in making the amplitude of both the signals at the attenuation region while being sent individually through the main circuit and the indirect coupling circuit and reaching the point P5 equal to each other, both the signals are cancelled together and no attenuation pole is caused to the frequency location of the signals. |
