Strip-line filter, duplexer, filter device, communication device, and method of adjusting characteristic of strip-line filter
AssigneeMurata Manufacturing Co., Ltd.
InventorsTatsuya Tsujiguchi, Shigeji Arakawa
Life of this patent
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Abstract
Resonator electrodes are provided on the upper face of a dielectric substrate. The ratios (W1/L1) and (W3/L3) of the electrode widths W1 and W3 to the electrode lengths L1 and L3 of the resonator electrodes of the first and last stages are set at substantially 1.05<W/L<1.95. Lead-out electrodes are connected to the resonator electrodes of the first and last stages on the opposite sides of the center axis which is a straight-line axis passing through the center positions of the resonator electrodes of the first and last stages. Thereby, an attenuation pole is generated on the lower band side of the pass-band.
Claims23
A strip-line filter comprising plural resonator electrodes each constituting half-wave resonators arranged in one direction on or inside of a substrate, and lead-out electrodes connected to the resonator electrodes of the first and last stages,
- at least one of the resonator electrodes of the first and last stages having a ratio (W/L) of an electrode width W to an electrode length L of substantially 0.5<W/L<0.95, in which the electrode length L is an electrode length of the resonator electrode measured perpendicular to the direction in which the resonator electrodes are arranged, and the electrode width W is an electrode width of said resonator electrode measured parallel to said arrangement direction,
- the lead-out electrodes being connected to the resonator electrodes of the first and last stages on the same side of the center axis, which is a straight line axis passing through the center positions along said length direction of the resonator electrodes of the first and last stages.
A strip-line filter comprising plural resonator electrodes each constituting half-wave resonators arranged in one direction on or inside of a substrate, and lead-out electrodes connected to the resonator electrodes of the first and last stages,
- at least one of the resonator electrodes of the first and last stages having a ratio (W/L) of an electrode width W to an electrode length L of substantially 0.1<W/L<0.95, in which the electrode length L is an electrode length of the resonator electrode measured perpendicular to the direction in which the resonator electrodes are arranged, and the electrode width W is an electrode width of said resonator electrode measured parallel to said arrangement direction,
- the lead-out electrodes being connected to the resonator electrodes of the first and last stages on the same side of the center axis, which is a straight line axis passing through the center positions along said length direction of the resonator electrodes of the first and last stages;
- and
- wherein a frequency adjustment electrode is formed on at least one of the plural resonator electrodes so as to protrude from said arrangement direction.
A strip-line filter comprising plural resonator electrodes each constituting half-wave resonators arranged in one direction on or inside of a substrate, and lead-out electrodes connected to the resonator electrodes of the first and last stages,
- at least one of the resonator electrodes of the first and last stages having a ratio (W/L) of an electrode width W to an electrode length L of substantially 0.1<W/L<0.95, in which the electrode length L is an electrode length of the resonator electrode measured perpendicular to the direction in which the resonator electrodes are arranged, and the electrode width W is an electrode width of said resonator electrode measured parallel to said arrangement direction,
- the lead-out electrodes being connected to the resonator electrodes of the first and last stages on the same side of the center axis, which is a straight line axis passing through the center positions alone said length direction of the resonator electrodes of the first and last stages;
- wherein an external coupling electrode is formed on at least one of the lead-out electrodes so as to protrude from said arrangement direction, and
- wherein said external coupling electrode protrudes perpendicularly to said arrangement direction.
A duplexer comprising two strip-line filters, a first lead-out electrode of one filter being connected to a receiving terminal, a first lead-out electrode of the other filter being connected to a transmitting terminal, and second lead-out electrodes of both filters being connected in common to an antenna terminal;
- wherein one of said two strip-line filters is a strip-line filter comprising plural resonator electrodes each constituting half-wave resonators arranged in one direction on or inside of a substrate, and lead-out electrodes connected to the resonator electrodes of the first and last stages,
- at least one of the resonator electrodes of the first and last stages having a ratio (W/L) of an electrode width W to an electrode length L of substantially 1.05<W/L<1.95, in which the electrode length L is an electrode length of the resonator electrode measured perpendicular to the direction in which the resonator electrodes are arranged, and the electrode width W is an electrode width of said resonator electrode measured parallel to said arrangement direction,
- the lead-out electrodes being connected to the resonator electrodes of the first and last stages on the opposite sides of the center axis, which is a straight line axis passing through the center positions along said length direction of the resonator electrodes of the first and last stages;
- and
- wherein the other strip-line filter is a strip-line filter comprising plural resonator electrodes each constituting half-wave resonators arranged in one direction on or inside of a substrate, and lead-out electrodes connected to the resonator electrodes of the first and last stages,
- at least one of the resonator electrodes of the first and last stages having a ratio (W/L) of an electrode width W to an electrode length L of substantially 0.1<W/L<0.95, in which the electrode length L is an electrode length of the resonator electrode measured perpendicular to the direction in which the resonator electrodes are arranged, and the electrode width W is an electrode width of said resonator electrode measured parallel to said arrangement direction,
- the lead-out electrodes being connected to the resonator electrodes of the first and last stages on the same side of the center axis, which is a straight line axis passing through the center positions along said length direction of the resonator electrodes of the first and last stages.
A method of adjusting a characteristic of a strip-line filter comprising plural resonator electrodes each constituting half-wave resonators arranged in one direction on or inside of a substrate, and lead-out electrodes connected to the resonator electrodes of the first and last stages, comprising the steps of:
- forming a frequency-adjustment electrode on at least one of the plural resonator electrodes so as to protrude from said arrangement direction;
- and
- removing a predetermined amount of the frequency adjustment electrode so as to adjust the center frequency of the filter.
A method of adjusting a characteristic of a strip-line filter comprising plural resonator electrodes each constituting half-wave resonators arranged in one direction on or inside of a substrate, and lead-out electrodes connected to the resonator electrodes of the first and last stages, comprising the steps of:
- forming an external coupling electrode on at least one of the lead-out electrodes so as to protrude from said arrangement direction;
- and
- removing a predetermined amount of the external coupling adjustment electrode so as to adjust external coupling of the filter.
A strip-line filter comprising plural resonator electrodes each constituting half-wave resonators arranged in one direction on or inside of a substrate, and lead-out electrodes connected to the resonator electrodes of the first and last stages,
- at least one of the resonator electrodes of the first and last stages having a ratio (W/L) of an electrode width W to an electrode length L of substantially 0.1<W/L<0.95, in which the electrode length L is an electrode length of the resonator electrode measured perpendicular to the direction in which the resonator electrodes are arranged, and the electrode width W is an electrode width of said resonator electrode measured parallel to said arrangement direction,
- the lead-out electrodes being connected to the resonator electrodes of the first and last stages on the same side of the center axis, which is a straight line axis passing through the center positions along said length direction of the resonator electrodes of the first and last stages;
- and
- wherein the resonator electrodes each have a rectangular shape.
Dependencies are inferred from the claim text.