Patent ID: 8725224

Claim:
A filter comprising: a dielectric substrate; an electrode layer continuously formed covering a first side of the dielectric substrate; a disk-shaped electrode pattern provided on a second side of the dielectric substrate, the disk-shaped electrode pattern and the electrode layer having the dielectric substrate therebetween; a ground slot having an opening that is formed asymmetrically with respect to the center of a circular area included in the electrode layer and exposes the dielectric substrate, the circular area, and the disk-shaped electrode pattern having the dielectric substrate therebetween; an input-side cutout portion that is formed in the electrode layer on the first side of the dielectric substrate so as to reach into the circular area and extends in a first direction; an output-side cutout portion that is formed in the electrode layer on the first side of the dielectric substrate so as to reach into the circular area and extends in a second direction perpendicular to the first direction; an input-side conductive pattern formed in the input-side cutout portion on the first side of the dielectric substrate so as to reach directly beneath the circular area and extends in the first direction beyond the circular area; a part of the input-side conductive pattern sandwich the dielectric substrate, and overlaps with the disk-shaped electrode pattern; and an output-side conductive pattern formed in the output-side cutout portion on the first side of the dielectric substrate so as to reach into the circular area and extends in the second direction, a part of the output-side conductive pattern sandwich the dielectric substrate, and overlaps with the disk-shaped electrode pattern.