Transmission line resonator filter

摘要

The invention relates to a radiofrequency filter in which the coupling between the transmission line resonators is effected by using both a slot coupling and a link coupling. The coupling slot and the coupling link are designed so that changes of the coupling intensity in the link coupling caused by shifting of the resonator element is of the same size and of the opposite sign as a corresponding change in the slot coupling, whereby the changes compensate one another. The design is based on the fact that the distance of the coupling link from the resonator is longer close to the coupling slot than far away from the coupling slot. <IMAGE>