LOW-PASS FILTER Russian patent published in 2007 - IPC H01P1/207 

FIELD: radio engineering, in particular, SHF and EHF equipment, applicable in various radio engineering devices, instruments, units for suppression of unwanted harmonics of the carrying signal, as well as of the high-type waves passing through the selected high-frequency channel.

SUBSTANCE: the low-pass filter has two halves of the body, in which the waveguide channel section is formed and a dielectric backing is introduced in the E-plane of the waveguide with the sections of asymmetric waveguide-slot lines applied on its two opposite surfaces passing to a balanced microband line. Made in the sections of this line are capacitive and inductive elements of the filter structure, located on the two opposite sides of the backing one relative each other. The dielectric backing has an H-shaped dumbbell shape, whose narrow part contains the capacitive and inductive elements of the filter structure, and the wide part of the backing contains the sections of the asymmetric waveguide-slot line. The narrow part of the backing is positioned in the narrow access of the body halves, and the wide one is positioned in the accesses for installation of the dielectric backing. The cross-sectional dimensions of the narrow access of the body halves and the width of the backing narrow part should not exceed a half of the wave length of the maximum frequency of the attenuation band. The inductive elements located on one side of the backing in one horizontal line are shifted in the cross direction relative to the inductive elements located on the opposite side of the backing, and the wave impedances of the inductive elements are increased at least by 1.5 times relative to the impedance of the inductive elements located relative to one another on the opposite sides of the backing. The inductive elements of the filter structure on each of the two surfaces of the backing may be made in the form of a meander and shifted relative to each other on the opposite sides of the backing.

EFFECT: improved quality of suppression of the unwanted harmonics of the carrying signal.

2 cl, 7 dwg