BANDPASS MICROWAVE FILTER Russian patent published in 2011 - IPC H01P1/203 

FIELD: electricity.

SUBSTANCE: device 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 four resonators, two capacitors for connection of a signal source and a load, three capacitors to provide an electric connection between neighbouring resonators, and also a transformer on joined transmission lines, which is connected by two arms between non-neighbouring resonators, and two its other arms are closed to the grounding screen. At the same time connection between the neighbouring first, second, third and fourth resonators are of capacitance type, and connection between the non-neighbouring first and fourth resonators is of inductance type. Each resonator may be arranged in the form of a section of a short-circuited strip line or in the form of a coaxial pin. The transformer may be arranged with the possibility to change the distance between joined transmission lines.

EFFECT: invention makes it possible to smoothly tune selectivity of a frequency characteristic, reduction of losses and increased selectivity near a working strip of the bandpass microwave filter without distortion of characteristics in the working strip.

4 cl, 3 dwg