NARROW-BAND SHF-FILTER Russian patent published in 2014 - IPC H01P1/20 

FIELD: electricity.

SUBSTANCE: narrow-band SHF-filter comprises a dielectric substrate, at one side of which there is a grounding screen, and at the other side - a microstrip structure, which realises filter elements with link chains. At the same time the microstrip structure includes six resonators, two capacitors for connection of a signal source and a load, five capacitors to provide an electric connection between neighbouring resonators, and also a transformer on joined transmission lines, which is connected by two arms between the non-neighbouring first and fourth resonators, and two its other arms are closed to the grounding screen, and a trimmer capacitor coupled between the non-neighbouring fourth and sixth resonators. At that coupling between of the neighbouring first, second, third, fourth, fifth and sixth resonators is of capacitance type, coupling between the non-neighbouring first and third resonators is of inductance type, and coupling between the non-neighbouring fourth and sixth resonators is of capacitance type.

EFFECT: provision of independent smooth adjustment of frequency response selectivity above and below the pass band without distortion in the operating band thus allowing effective suppression of interference signals both symmetrical and non-symmetrical at both sides of the filter band.

5 cl, 6 dwg