Patent ID: 7629867
Filing Date: 2009-12-08
Classification: H01P

Abstract:
1. A filter element comprising: a flat dielectric substrate; a ground electrode on a back main surface of the dielectric substrate; resonant lines each having a shorting end located in an area of a border between a side surface and the back main surface of the dielectric substrate and extending from the side surface to a front main surface of the dielectric substrate, wherein the ground electrode and the resonant lines constitute a plurality of strip-line resonators; and an input/output terminal coupled to any of the plurality of strip-line resonators; wherein in any of the plurality of strip-line resonators, a line width of substantially the entire portion of the resonant line on the front main surface is different from a line width of the resonant line of the strip-line resonator on the side surface; and the line width of at least one of the resonant lines on the side surface is less than the line width of the resonator lines on the front surface, and the line width of at least another one of the resonator lines on the side surface is greater than the line width of the resonator lines on the on the front surface.