Input coupling adjustment arrangement for radio frequency filters

摘要

An arrangement for adjustably coupling a radio frequency input port to a resonator element of the filter. The arrangement comprises a resilient conductor (19) which extends from the input port (15) into the electric field of a resonator element (2). The remote end of the resilient conductor resiliently abuts the point (20) of an adjustment screw (20a). Operating the screw moves the resilient conductor in relation to the electric field and alters the capacitive coupling between the input port and the resonator element for fine tuning the impedance match of the input to the filter.