Strip-line resonator and a band pass filter having the same
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsMitsuo Makimoto, Sadahiko Yamashita
Life of this patent
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Abstract
The width of a strip-line conductor in a TEM mode resonator is made wider at the center portion thereof, at which current is maximum, then the open-ended widths at both end portions of the conductor so that impedance of the center portion is lower than the impedances of both end portions. The impedance may be stepwisely or continuously varied, and spurious resonance frequencies may be determined by the impedance ratio between the higher and lower impedances. Such a resonator may be included in a band pass filter in such a manner that the band pass filter comprises at least one resonator whose spurious resonance frequencies differ from those of remaining resonators.
Claims18
A strip-line resonator comprising:
- (a) a substrate made of a dielectric;
- (b) a ground-plane conductor attached to one surface of said substrate;
- and
- (c) a strip-line conductor placed on the other surface of said substrate, said strip-line conductor being formed of first and second open-ended conductors and a center conductor interposed between said first and second open-ended conductors, the impedance of said center conductor being lower than the impedances of said first and second open-ended conductors.
A band pass filter comprising a plurality of resonators in which at least one of said plurality of resonators is formed of a line of uniform-width and at least one other of said plurality of resonators is formed of a line having narrow and wide portions so that at least one of said resonators shows spurious resonance frequencies which are different from those of remaining resonators.
Dependencies are inferred from the claim text.