# US 2013/0154768 A1 · Laminated balanced filter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0154768 A1 - Document ID: US20130154768A1 - Status: Published application - Kind: A1 - Application number: 13/688,537 - Filed: 2012-11-29 - Published: 2013-06-20 - Earliest claimed: 2011-11-30 - Assignees: Murata Manufacturing Co., Ltd. - Inventors: Tetsuo TANIGUCHI - Web page: https://patentgrep.com/patent/US20130154768A1 ## CPC - H03H 7/09: Filters comprising mutual inductance - H03H 7/12: Bandpass or bandstop filters with adjustable bandwidth and fixed centre frequency (H03H7/09 takes precedence) - H03H 7/42: Networks for transforming balanced signals into unbalanced signals and vice versa, e.g. baluns - H03H 7/1708: {Comprising bridging elements, i.e. elements in a series path without own reference to ground and spanning branching nodes of another series path (H03H7/07 takes precedence)} - H03H 7/1775: {Parallel LC in shunt or branch path (H03H7/1791 takes precedence)} - H03H 2001/0085: {Multilayer, e.g. LTCC, HTCC, green sheets} - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract A laminated balanced filter includes one unbalanced terminal, two balanced terminals, a ground terminal, an unbalanced-side LC parallel resonator, an intermediate LC parallel resonator, and a balanced-side inductor. The inductor electrode pattern of the balanced-side inductor includes a first portion extending from one end portion to a connection portion and a second portion extending from the other end portion to the connection portion. A direction of a current flowing through the first portion is opposite to a direction of a current flowing through the inductor electrode pattern of the intermediate LC parallel resonator. A direction of a current flowing through the second portion of the balanced-side inductor is the same as a direction of a current flowing through the inductor electrode pattern of the intermediate LC parallel resonator. The laminated balanced filter further includes a coupling capacitor connected between a balanced terminal connected to the first portion and an unbalanced terminal. ## Claims ### Claim 1 A laminated balanced filter comprising: a laminated body including a plurality of dielectric layers and a plurality of electrode patterns located on the dielectric layers; one unbalanced terminal; two balanced terminals; a ground terminal; an unbalanced-side LC parallel resonator including one end portion connected to the ground terminal and another end portion connected to the unbalanced terminal; a balanced-side inductor including two end portions that are individually connected to the balanced terminals; and at least one intermediate LC parallel resonator including one end portion connected to the ground terminal and disposed between the unbalanced-side LC parallel resonator and the balanced-side inductor; wherein the unbalanced-side LC parallel resonator and an intermediate LC parallel resonator disposed nearest to the unbalanced-side LC parallel resonator among the intermediate LC parallel resonators are electromagnetic-field-coupled to each other; the balanced-side inductor and an intermediate LC parallel resonator disposed nearest to the balanced-side inductor among the intermediate LC parallel resonators are electromagnetic-field-coupled to each other; the unbalanced terminal, the balanced terminal, and the ground terminal are provided on the laminated body; the balanced-side inductor includes an inductor electrode pattern on a predetermined dielectric layer of the laminated body, wherein a connection portion in a central portion or approximately central portion of the inductor electrode pattern is connected to the ground terminal and includes a first portion extending from one end portion thereof to the connection portion and a second portion extending from the other end portion thereof to the connection portion; the intermediate LC parallel resonator includes an inductor electrode pattern on a layer of the laminated body and that is different from the inductor electrode pattern of the balanced-side inductor; a direction of a current flowing through the first portion of the inductor electrode pattern of the balanced-side inductor is opposite to a direction of a current flowing through the inductor electrode pattern of the intermediate LC parallel resonator and a direction of a current flowing through the second portion of the inductor electrode pattern of the balanced-side inductor is the same as the direction of the current flowing through the inductor electrode pattern of the intermediate LC parallel resonator; and the laminated balanced filter further includes a coupling capacitor connected between the balanced terminal connected to the first portion side and the unbalanced terminal. ### Claim 2 (depends on 1) The laminated balanced filter according to claim 1, wherein the balanced-side inductor and the inductor electrode pattern of the intermediate LC parallel resonator have substantially helical shapes. ### Claim 3 (depends on 2) The laminated balanced filter according to claim 2, wherein at least portions of an aperture of the inductor electrode pattern of the intermediate LC parallel resonator and an aperture of the inductor electrode pattern of the balanced-side inductor overlap with each other when being viewed from a lamination direction. ### Claim 4 (depends on 2) The laminated balanced filter according to claim 2, wherein positions of central axes of an aperture of the inductor electrode pattern of the intermediate LC parallel resonator and an aperture of the inductor electrode pattern of the balanced-side inductor coincide with each other when being viewed from a lamination direction. ### Claim 5 (depends on 3) The laminated balanced filter according to claim 3, wherein positions of central axes of an aperture of the inductor electrode pattern of the intermediate LC parallel resonator and an aperture of the inductor electrode pattern of the balanced-side inductor coincide with each other when being viewed from a lamination direction. ### Claim 6 (depends on 2) The laminated balanced filter according to claim 2, wherein the unbalanced-side LC parallel resonator includes a substantially helical-shaped inductor electrode pattern, and a circling direction of the inductor electrode pattern of the unbalanced-side LC parallel resonator and a circling direction of the inductor electrode pattern of the intermediate LC parallel resonator are opposite to each other when being viewed from a lamination direction. ### Claim 7 (depends on 3) The laminated balanced filter according to claim 3, wherein the unbalanced-side LC parallel resonator includes a substantially helical-shaped inductor electrode pattern, and a circling direction of the inductor electrode pattern of the unbalanced-side LC parallel resonator and a circling direction of the inductor electrode pattern of the intermediate LC parallel resonator are opposite to each other when being viewed from a lamination direction. ### Claim 8 (depends on 4) The laminated balanced filter according to claim 4, wherein the unbalanced-side LC parallel resonator includes a substantially helical-shaped inductor electrode pattern, and a circling direction of the inductor electrode pattern of the unbalanced-side LC parallel resonator and a circling direction of the inductor electrode pattern of the intermediate LC parallel resonator are opposite to each other when being viewed from a lamination direction. ### Claim 9 (depends on 5) The laminated balanced filter according to claim 5, wherein the unbalanced-side LC parallel resonator includes a substantially helical-shaped inductor electrode pattern, and a circling direction of the inductor electrode pattern of the unbalanced-side LC parallel resonator and a circling direction of the inductor electrode pattern of the intermediate LC parallel resonator are opposite to each other when being viewed from a lamination direction. ### Claim 10 (depends on 1) The laminated balanced filter according to claim 1, wherein each inductor electrode pattern and a capacitor electrode pattern of the laminated balanced filter are separately disposed on one main surface side and another main surface side in a lamination direction of the laminated body. ### Claim 11 (depends on 2) The laminated balanced filter according to claim 2, wherein each inductor electrode pattern and a capacitor electrode pattern of the laminated balanced filter are separately disposed on one main surface side and another main surface side in a lamination direction of the laminated body. ### Claim 12 (depends on 3) The laminated balanced filter according to claim 3, wherein each inductor electrode pattern and a capacitor electrode pattern of the laminated balanced filter are separately disposed on one main surface side and another main surface side in a lamination direction of the laminated body. ### Claim 13 (depends on 4) The laminated balanced filter according to claim 4, wherein each inductor electrode pattern and a capacitor electrode pattern of the laminated balanced filter are separately disposed on one main surface side and another main surface side in a lamination direction of the laminated body. ### Claim 14 (depends on 5) The laminated balanced filter according to claim 5, wherein each inductor electrode pattern and a capacitor electrode pattern of the laminated balanced filter are separately disposed on one main surface side and another main surface side in a lamination direction of the laminated body. ### Claim 15 (depends on 6) The laminated balanced filter according to claim 6, wherein each inductor electrode pattern and a capacitor electrode pattern of the laminated balanced filter are separately disposed on one main surface side and another main surface side in a lamination direction of the laminated body. ### Claim 16 (depends on 7) The laminated balanced filter according to claim 7, wherein each inductor electrode pattern and a capacitor electrode pattern of the laminated balanced filter are separately disposed on one main surface side and another main surface side in a lamination direction of the laminated body. ### Claim 17 (depends on 8) The laminated balanced filter according to claim 8, wherein each inductor electrode pattern and a capacitor electrode pattern of the laminated balanced filter are separately disposed on one main surface side and another main surface side in a lamination direction of the laminated body. ### Claim 18 (depends on 9) The laminated balanced filter according to claim 9, wherein each inductor electrode pattern and a capacitor electrode pattern of the laminated balanced filter are separately disposed on one main surface side and another main surface side in a lamination direction of the laminated body. ### Claim 19 (depends on 1) The laminated balanced filter according to claim 1, wherein an inductor electrode pattern and a capacitor electrode pattern of the unbalanced-side LC parallel resonator are separately disposed on one main surface side and another main surface side in a lamination direction of the laminated body and the inductor electrode pattern of the intermediate LC parallel resonator and the inductor electrode pattern of the balanced-side inductor are disposed therebetween. ### Claim 20 (depends on 2) The laminated balanced filter according to claim 2, wherein an inductor electrode pattern and a capacitor electrode pattern of the unbalanced-side LC parallel resonator are separately disposed on one main surface side and another main surface side in a lamination direction of the laminated body and the inductor electrode pattern of the intermediate LC parallel resonator and the inductor electrode pattern of the balanced-side inductor are disposed therebetween.