AN ADJUSTABLE COUPLING FOR USE WITH AN INPUT RESONATOR AND/OR AN OUTPUT RESONATOR OF A BANDPASS FILTER

摘要

The invention provides an adjustable coupling for use with an input resonator and/or an output resonator of a bandpass filter. According to an embodiment of the invention, an input resonator comprising the adjustable coupling, an output resonator comprising the adjustable coupling and a bandpass filter comprising the abovementioned input resonator and/or the abovementioned output resonator. According to an embodiment of the invention, the adjustable coupling comprises: an inductive loop including a first portion connected with the coaxial port and secured at the bottom of the cavity and an extension extending upwards from the first portion and an adjusting element spaced from the inductive loop and subjected to influence from capacitive coupling between the inductive loop and the resonator rod, wherein the adjusting element is adapted for displacement between a first position in which input coupling strength is maximized and a second position in which the input coupling strength is minimized, by adjusting the interaction between the inductive loop and the resonator rod via the extension.