JP2009212229A - Stacked filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stacked filter of which a DC resistance is reduced, with the size of a component being reduced. <P>SOLUTION: A coil part 10 includes a non-magnetic layer 11, a magnetic layer 13 arranged to sandwich at least the non-magnetic layer 11, and first and second spiral coil conductors 15 and 17 which are arranged in the non-magnetic layer 11 to couple each other magnetically. The first and second spiral coil conductors 15 and 17 comprise stacked conductor patterns 16a, 16b, 18a and 18b. The conductor patterns 16a, 16b, 18a and 18b are formed in spiral, comprising an outermost turn portion, a central turn portion, and an innermost turn portion. The conductor width of the outermost turn portion is set larger than that of the central turn portion and innermost turn portion. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multilayer filter provided with a coil portion.

A nonmagnetic layer, a magnetic layer disposed so as to sandwich at least the nonmagnetic layer, and first and second spiral coil conductors disposed in the nonmagnetic layer and magnetically coupled to each other; Are known (for example, see Patent Document 1).
JP 2006-210579 A

In recent years, due to the demand for downsizing of electronic devices, downsizing of multilayer filters is also required. As the multilayer filter is downsized, the conductor widths of the first and second spiral coil conductors must be reduced, and the cross-sectional areas of the first and second spiral coil conductors are inevitably reduced. End up. For this reason, the direct current resistance (R _dc ) of the multilayer filter (first and second spiral coil conductors) tends to increase.

  An object of the present invention is to provide a multilayer filter capable of reducing DC resistance while reducing the size of components.

  The present invention relates to a multilayer filter including a coil portion, the coil portion being disposed in the nonmagnetic layer, a nonmagnetic layer, a magnetic layer disposed so as to sandwich at least the nonmagnetic layer, and the nonmagnetic layer. And first and second spiral coil conductors that are magnetically coupled to each other in the nonmagnetic layer, and the first and second spiral coil conductors have a number of turns of a plurality of turns. In addition, the conductor width of the outermost turn part is larger than the conductor width of the turn parts other than the outermost turn part.

  If the conductor width is increased in all the turn portions of the first and second spiral coil conductors, the sizes of the first and second spiral coil conductors are increased, which is contrary to the miniaturization of the multilayer filter. become. It is conceivable to absorb the increase in the conductor width of the first and second spiral coil conductors by narrowing the distance between the turn parts. There is a possibility that a new problem such as a short circuit may occur, and there is a limit in reducing the interval between the turn portions.

  Paying attention to one spiral coil conductor, the outermost turn part has no turn part adjacent to the outside, and the innermost turn part has no turn part adjacent to the inside. Therefore, there is a margin for increasing the conductor width as compared with other turn portions.

  In the first and second spiral coil conductors, the line length of the outermost turn portion among the portions of the plurality of turns is the longest because of the shape. For this reason, the DC resistance of the outermost turn portion is larger than the DC resistance of each turn portion other than the outermost turn portion, and the influence on the DC resistance of the first and second spiral coil conductors is the greatest. Larger than each turn part other than the outer turn part.

  From the above, in the present invention, the conductor width of the outermost turn portion in the first and second spiral coil conductors is set larger than the conductor width of the turn portion other than the outermost turn portion. Thereby, it is possible to reduce the direct current resistance while suppressing an increase in the size of the entire first and second spiral coil conductors.

  By the way, in Japanese terrestrial digital television broadcasting (ISDB-T), it is possible to partially receive only one segment out of 13 segments. One segment digital broadcasting, so-called one-segment broadcasting, can be used for mobile phones and mobiles. A service for mobile terminals (one-segment partial reception service for mobile phones and mobile terminals) has been started. Therefore, the multilayer filter mounted as an EMC countermeasure component etc. on a communication terminal such as a mobile phone compatible with 1Seg broadcasting is designed to have a high common mode noise attenuation characteristic at 470 to 770 MHz, which is a carrier frequency in 1Seg broadcasting. There is a need to. Further, attenuation characteristics at 800 to 950 MHz and 1.8 to 2.3 GHz, which are communication frequencies in a communication terminal such as a mobile phone, are also required.

  In order to support terrestrial digital media broadcasting (T-DMB) adopted in some countries in Korea and Europe, it is necessary to design a high attenuation characteristic of common mode noise at 174 to 245 MHz.

  In view of this, it further includes a capacitance generating unit having a functional layer having dielectric characteristics and a plurality of internal electrodes disposed in the functional layer and facing each other, and the relative permeability of the magnetic layer is in the range of 35 to 120. The resonance frequency of the coil portion is in the range of 470 to 770 MHz, the resonance frequency of the capacitance generation portion is in the range of 0.8 to 2.3 GHz, and the cutoff frequency for normal mode noise is 100 MHz or more. preferable.

  The relative permeability of the magnetic layer is in the range of 35 to 120, the resonance frequency of the coil portion is in the range of 470 to 770 MHz, the resonance frequency of the capacitance generating portion is in the range of 0.8 to 2.3 GHz, and normal Since the cut-off frequency for mode noise is 100 MHz or more, a multilayer filter having attenuation characteristics suitable for a communication terminal such as a mobile phone that supports one-segment broadcasting can be realized.

  In addition, it further includes a capacitance generating unit having a functional layer having dielectric characteristics and a plurality of internal electrodes disposed in the functional layer and facing each other, and the relative permeability of the magnetic layer is in the range of 380 to 755. The resonance frequency of the coil portion is in the range of 174 to 245 MHz, the resonance frequency of the capacitance generation portion is in the range of 0.8 to 2.3 GHz, and the cutoff frequency for normal mode noise is 100 MHz or more. preferable.

  The relative permeability of the magnetic layer is in the range of 380 to 755, the resonance frequency of the coil portion is in the range of 174 to 245 MHz, the resonance frequency of the capacitance generating portion is in the range of 0.8 to 2.3 GHz, and normal Since the cut-off frequency for mode noise is 100 MHz or more, a multilayer filter having attenuation characteristics suitable for a communication terminal such as a mobile phone that supports terrestrial digital media broadcasting can be realized.

  In order to achieve good attenuation characteristics in frequency bands such as 174 to 245 MHz and 470 to 770 MHz, it is necessary to increase the inductance value of the coil section. In the case where the coil portion has only a nonmagnetic layer, a method of increasing the number of turns of the spiral coil conductor can be considered in order to increase the inductance value. However, in this case, there are problems such as an increase in the direct current resistance of the spiral coil conductor, an increase in the cost of the multilayer filter, and an increase in outer dimensions. On the other hand, when the coil part has only a magnetic body, although the inductance value becomes high, there arises a problem that the leakage magnetic flux increases.

  On the other hand, the coil portion has a nonmagnetic layer and a magnetic layer disposed so as to sandwich at least the nonmagnetic layer, and the first and second spiral coil conductors are nonmagnetic. Since it is arranged in the layer, the inductance value can be set high without causing the above-mentioned problems. In addition, since the first and second spiral coil conductors are not in contact with the magnetic layer, eddy current loss generated in the coil portion can be reduced.

  The present invention also relates to a multilayer filter including a coil part, the coil part being disposed in the nonmagnetic layer and the nonmagnetic layer, and being magnetically coupled to each other in the nonmagnetic layer. First and second spiral coil conductors, wherein the first and second spiral coil conductors have a plurality of turns and the outermost turn portion has a conductor width of the outermost turns. It is characterized by being larger than the conductor width of the turn part other than the turn part.

  In the present invention, as described above, the conductor width of the outermost turn portion in the first and second spiral coil conductors is set larger than the conductor width of the turn portion other than the outermost turn portion. The direct current resistance can be lowered while suppressing an increase in the overall size of the first and second spiral coil conductors.

  ADVANTAGE OF THE INVENTION According to this invention, the multilayer filter which can reduce direct-current resistance can be provided, aiming at size reduction of components.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  With reference to FIGS. 1-4, the structure of multilayer filter MF1 which concerns on this embodiment is demonstrated. FIG. 1 is a perspective view of the multilayer filter according to the present embodiment. FIG. 2 is an exploded perspective view of the element body constituting the multilayer filter according to the present embodiment. FIG. 3 is a schematic diagram showing a cross-sectional configuration of an element body constituting the multilayer filter according to the present embodiment. FIG. 4 is a plan view showing a conductor pattern of the first spiral coil conductor. FIG. 5 is a plan view showing a conductor pattern of the second spiral coil conductor. FIG. 6 is a diagram showing an equivalent circuit of the multilayer filter according to the present embodiment.

  The multilayer filter MF1 is an array-type multilayer composite electronic component having a common mode filter function and a capacity generation function. As shown in FIG. 1, the multilayer filter MF1 includes an element body EB1 having a substantially rectangular parallelepiped shape, Fifth terminal electrodes 1 to 5 are provided. The first and third terminal electrodes 1 and 3 are arranged on one side surface extending in the longitudinal direction of the element body EB1, and the second and fourth terminal electrodes 2 and 4 extend in the longitudinal direction of the element body EB1. And it is arrange | positioned at the other side surface opposite to one side surface. The fifth terminal electrodes are arranged at both ends in the longitudinal direction of the element body EB1. The first to fourth terminal electrodes 1 to 4 function as input / output terminals, and the fifth terminal electrode functions as a ground terminal.

  As shown in FIGS. 2 and 3, the element body EB <b> 1 includes a coil part 10, a capacity generation part 20, and an intermediate part 30.

  The coil unit 10 includes a nonmagnetic layer 11, a pair of magnetic layers 13, and a plurality of pairs (two pairs in this embodiment) of first and second spiral coil conductors 15 and 17, respectively. is doing.

  The nonmagnetic material layer 11 is a portion in which a plurality of layers 12 a to 12 f made of a nonmagnetic material are laminated, and is formed by being integrally fired with the capacitance generating portion 20 and the intermediate portion 30. The first and second spiral coil conductors 15 and 17 are arranged between the plurality of layers 12 a to 12 f, that is, in the nonmagnetic layer 11. The nonmagnetic layer 11 (the plurality of layers 12a to 12f) is made of, for example, a Cu—Zn-based ferrite material.

  The first spiral coil conductor 15 includes laminated conductor patterns 16a and 16b. The conductor pattern 16a is located between the layers 12a and 12b, and the conductor pattern 16b is located between the layers 12b and 12c. The conductor patterns 16a and 16b are formed in a spiral shape from the center toward the edge. The conductor pattern 16 a has an outer end drawn out to the one side surface of the element body EB <b> 1 and connected to the first terminal electrode 1. The outer end of the conductor pattern 16b is drawn out to the other side surface of the element body EB1, and is connected to the second terminal electrode 2. The inner end of the conductor pattern 16a and the inner end of the conductor pattern 16b are electrically connected through a via conductor 16c disposed through the layer 12b.

As shown in FIGS. 4A and 4B, the conductor patterns 16a and 16b include outermost turn portions 16a ₁ and 16b ₁ , central turn portions 16a ₂ and 16b ₂ , and innermost turn portions. 16a ₃ and 16b ₃ and the number of turns is set to about 3 turns. The conductor width W1 of the outermost turn portions 16a ₁ and 16b ₁ is set to be larger than the conductor width W2 of the center turn portions 16a ₂ and 16b ₂ and the innermost turn portions 16a ₃ and 16b ₃ . Conductor thickness of each turn portion _{16a 1, 16b 1, 16a 2} , 16b 2, 16a 3, 16b 3 are set the same.

In the present embodiment, the conductor width W1 of the outermost turn portions 16a ₁ and 16b ₁ is set to 0.040 mm, and the conductor widths of the center turn portions 16a ₂ and 16b ₂ and the innermost turn portions 16a ₃ and 16b ₃ are set. W2 is set to 0.035 mm. The distance between adjacent turn parts, that is, the distance between the outermost turn parts 16a ₁ , 16b ₁ and the central turn parts 16a ₂ , 16b ₂ and the central turn parts 16a ₂ , 16b ₂ and the innermost turn part 16a ₃ , 16b ₃ is set to 0.035 mm. Conductor thickness of each turn portion _{16a 1, 16b 1, 16a 2} , 16b 2, 16a 3, 16b 3 is set to 0.012 mm. The direct current resistance of the first spiral coil conductor 15 is set to 1.0Ω.

  The second spiral coil conductor 17 includes laminated conductor patterns 18a and 18b. The conductor pattern 18a is located between the layers 12e and 12f, and the conductor pattern 18b is located between the layers 12d and 12e. The conductor patterns 18a and 18b are formed in a spiral shape from the center toward the edge. The outer end portion of the conductor pattern 18a is drawn out to the one side surface of the element body EB1 and connected to the third terminal electrode 3. The outer end portion of the conductor pattern 18b is drawn out to the other side surface of the element body EB1 and connected to the fourth terminal electrode 4. The inner end of the conductor pattern 18a and the inner end of the conductor pattern 18b are electrically connected through a via conductor 18c disposed through the layer 12e.

As shown in FIGS. 5A and 5B, the conductor patterns 18a and 18b are formed by outermost turn portions 18a ₁ and 18b ₁ , central turn portions 18a ₂ and 18b ₂ , and innermost turn portions. 18a ₃ and 18b ₃ and the number of turns is set to about 3 turns. The conductor width W3 of the outermost turn portions 18a ₁ and 18b ₁ is set larger than the conductor width W4 of the center turn portions 18a ₂ and 18b ₂ and the innermost turn portions 18a ₃ and 18b ₃ . Conductor thickness of each turn portion _{18a 1, 18b 1, 18a 2} , 18b 2, 18a 3, 18b 3 are set the same.

In the present embodiment, the conductor width W3 of the outermost turn portions 18a ₁ and 18b ₁ is set to 0.040 mm, and the conductor widths of the center turn portions 18a ₂ and 18b ₂ and the innermost turn portions 18a ₃ and 18b ₃ are set. W4 is set to 0.035 mm. The distance between adjacent turn portions, that is, the distance between the outermost turn portions 18a ₁ and 18b ₁ and the central turn portions 18a ₂ and 18b ₂ , and the center turn portions 18a ₂ and 18b ₂ and the innermost turn portion 18a _3. , 18b ₃ is set to 0.035 mm. Conductor thickness of each turn portion _{18a 1, 18b 1, 18a 2} , 18b 2, 18a 3, 18b 3 is set to 0.012 mm. The DC resistance of the second spiral coil conductor 17 is set to 1.0Ω.

  The first and second spiral coil conductors 15 and 17 are stacked via layers 12c and 12d. As a result, the first and second spiral coil conductors 15 and 17 are magnetically coupled to each other in the nonmagnetic layer 11. In the present embodiment, the coupling coefficient of the first and second spiral coil conductors 15 and 17 is set to 0.6 or more. Moreover, the inductance value of the coil part 10 is set to 10-200 nH.

  As the conductive material used for the conductor patterns 16a, 16b, 18a, 18b and the via conductors 16c, 18c, a metal material that can be fired simultaneously with the nonmagnetic layer 11 is used. That is, since the firing temperature of ferrite is usually about 800 ° C. to 1400 ° C., a metal material that does not melt at that temperature is used. For example, Ag, Pd, or an alloy thereof can be preferably used.

  The pair of magnetic layers 13 are arranged so as to sandwich at least the nonmagnetic layer 11. That is, the pair of magnetic layers 13 sandwich the nonmagnetic layer 11 in the stacking direction of the plurality of layers 12a to 12f. Each magnetic layer 13 is a portion formed by laminating a plurality of layers 14 a and 14 b made of a magnetic material, and is formed by firing integrally with the nonmagnetic material layer 11. The magnetic layer 13 (the plurality of layers 14a and 14b) is made of, for example, a Ni—Cu—Zn based ferrite material. The relative permeability of the magnetic layer 13 is set in the range of 35 to 120.

  The capacitance generating unit 20 includes a functional layer 21 having dielectric characteristics and first to third internal electrodes 23, 25, and 27. The capacity generation unit 20 has a plurality of pairs (in this embodiment, two pairs) of second and third internal electrodes 25 and 27. The first internal electrode 23 functions as a ground electrode, and the second and third internal electrodes 25 and 27 function as hot electrodes.

The functional layer 21 is a portion formed by laminating a plurality of layers 22a to 22i made of a dielectric. The first to third internal electrodes 23, 25, 27 are disposed between the plurality of layers 22 b to 22 g, that is, in the functional layer 21. The functional layer 21 (the plurality of layers 22a to 22i) is made of, for example, a dielectric ceramic (a dielectric ceramic such as a BaTiO ₃ system, a Ba (Ti, Zr) O ₃ system, or a (Ba, Ca) TiO ₃ system). .

  The first internal electrodes 23 are located between the layers 22b and 22c, between the layers 22d and 22e, and between the layers 22f and 22h, respectively. The first internal electrode 23 includes a main electrode portion 23a extending in the longitudinal direction of the element body EB1, and a lead portion 23b formed integrally with the main electrode portion 23a. The lead portion 23b is drawn to the end face in the longitudinal direction of the element body EB1, and is connected to the fifth terminal electrode 5, respectively.

  The second internal electrode 25 is located between the layer 22c and the layer 22d. The second internal electrode 25 includes a main electrode portion 25a opposed to the main electrode portion 23a of the first internal electrode 23 across the layers 22c and 22d, and a lead portion 25b formed integrally with the main electrode portion 25a. Contains. The lead portion 25b is drawn to the other side surface of the element body EB1 and connected to the second terminal electrode 2.

  The third internal electrode 27 is located between the layer 22e and the layer 22f. The third internal electrode 27 includes a main electrode portion 27a opposed to the main electrode portion 23a of the first internal electrode 23 with the layers 22e and 22f interposed therebetween, and a lead portion 27b formed integrally with the main electrode portion 27a. Contains. The lead portion 27 b is drawn to the other side surface of the element body EB 1 and connected to the fourth terminal electrode 4.

  Of the layers 22c to 22f, portions overlapping the main electrode portion 23a of the first internal electrode 23 and the main electrode portions 25a and 27a of the second and third internal electrodes 25 and 27 are respectively capacitance components. Is a region that substantially generates Accordingly, a capacitance component is formed by the main electrode portion 23 a of the first internal electrode 23 and the main electrode portion 25 a of the second internal electrode 25. In addition, a capacitance component is formed by the main electrode portion 23 a of the first internal electrode 23 and the main electrode portion 27 a of the third internal electrode 27. The capacitance of the capacitance generator 20 is set to 4 to 100 pF.

  As the conductive material used for the first to third internal electrodes 23, 25, 27, a metal material that can be fired simultaneously with the ceramic material constituting the functional layer 21 is used. That is, since the firing temperature of the dielectric ceramic is usually about 800 ° C. to 1400 ° C., a metal material that does not melt at that temperature is used. For example, Ag, Pd, or an alloy thereof can be preferably used.

The intermediate part 30 is located between the coil part 10 and the capacity generation part 20 and is composed of a layer 31. The intermediate part 30 is a part provided for the purpose of adjusting the reduction ratio between the coil part 10 and the capacity generation part 20. Layer 31 is made of, for example, a _Fe 2 _{O 3} and the dielectric ceramic ceramic material mainly.

  In the actual multilayer filter MF1, the layers 12a to 12f, 14a, 14b, 22a to 22i, and 31 are integrated to such an extent that the boundary between them cannot be visually recognized.

  Next, a method for manufacturing the multilayer filter MF1 described above will be described.

  First, nonmagnetic green sheets that will form the layers 12a to 12f are prepared. As the non-magnetic green sheet, for example, a slurry formed by applying a slurry of Cu-Zn ferrite powder as a raw material on a PET film by a doctor blade method can be used.

  In addition, a magnetic green sheet that constitutes the layers 14a and 14b is prepared. As the magnetic green sheet, for example, a slurry obtained by applying a slurry of Ni-Cu-Zn ferrite powder as a raw material on a PET film by a doctor blade method can be used.

Also, a dielectric green sheet that will constitute the layers 22a to 22i is prepared. As the dielectric green sheet, for example, a slurry obtained by applying a slurry of BaTiO ₃ based dielectric ceramic powder as a raw material on a PET film by a doctor blade method can be used.

Also, an insulator green sheet that will form the layer 31 is prepared. As the insulator green sheet, for example, a slurry obtained by applying a slurry using a mixed powder of Fe ₂ O ₃ and the dielectric ceramic powder as a raw material on a PET film by a doctor blade method can be used.

  Next, through-holes are formed at predetermined positions of the nonmagnetic green sheets constituting the layers 12b and 12e, that is, positions where via conductors 16c and 18c are to be formed. The through hole can be formed by a laser processing machine or the like.

  Next, paste patterns corresponding to the conductor patterns 16a, 16b, 18a, and 18b are formed on the green sheets that constitute the layers 12b, 12c, 12e, and 12f. Each paste pattern is formed, for example, by screen-printing a conductor paste (conductor material) containing Ag, Pd, an alloy thereof, or the like as a main component and then drying. Each through hole is filled with a conductive paste when each paste pattern is formed.

  Further, paste patterns corresponding to the first to third internal electrodes 23, 25, and 27 are formed on each dielectric green sheet that constitutes the layers 22c to 22g. Each paste pattern is formed, for example, by screen-printing a conductor paste (conductor material) containing Ag, Pd, an alloy thereof, or the like as a main component and then drying.

  Next, a non-magnetic green sheet on which a predetermined paste pattern is formed, a non-magnetic green sheet on which a predetermined paste pattern is not formed, a dielectric green sheet on which a predetermined paste pattern is formed, and a predetermined A dielectric green sheet on which a paste pattern is not formed and an insulator green sheet are laminated in a desired order, further pressed, and then cut into a predetermined shape to obtain a green laminated body. Thereafter, the green laminate is baked under predetermined conditions (for example, 1100 ° C. to 1200 ° C. in the air) to obtain the element body EB1.

  Next, a conductive paste is applied to the end of the element body EB1 in the longitudinal direction and the center of both side surfaces in the longitudinal direction, and heat treatment is performed under a predetermined condition (for example, 700 ° C. to 800 ° C. in the atmosphere) to Bake. As the conductive paste, a paste containing powder containing Ag as a main component can be used. Thereafter, the surface of the external electrode is plated to obtain the multilayer filter MF1 in which the first to fifth terminal electrodes 1 to 5 are formed. The plating is preferably electrolytic plating, and for example, Ni / Sn, Cu / Ni / Sn, Ni / Pd / Au, Ni / Pd / Ag, Ni / Ag, or the like can be used.

  Next, the attenuation characteristics of the multilayer filter MF1 with respect to common mode noise and normal mode noise will be described with reference to FIGS.

  The characteristics shown in FIG. 7 are that the relative permeability of the magnetic layer 13 is set to 83, the inductance value of the coil unit 10 is set to 72 nH, the capacitance of the capacitance generating unit 20 is set to 22 pF, and the coupling coefficient Is the attenuation characteristic when. Is set to 0.85. The characteristics shown in FIG. 8 are that the relative permeability of the magnetic layer 13 is set to 83, the inductance value of the coil unit 10 is set to 72 nH, the capacitance of the capacitance generating unit 20 is set to 35 pF, and the coupling coefficient Is the attenuation characteristic when. Is set to 0.85. A characteristic cc indicates an attenuation characteristic with respect to common mode noise, and a characteristic dd indicates an attenuation characteristic with respect to normal mode noise.

  As can be seen from FIGS. 7 and 8, in the multilayer filter MF1, the resonance frequency of the coil unit 10 is in the range of 470 to 770 MHz, and the resonance frequency of the capacitance generation unit 20 is in the range of 0.8 to 2.3 GHz. . Further, the cutoff frequency (frequency at which the insertion loss is −3 dB) for normal mode noise is 100 MHz or more.

As described above, in the present embodiment, the outermost turn portions 16a ₁ , 16b ₁ , 18a ₁ , 18b _{1 in} the conductor patterns 16a, 16b, 18a, 18b of the first and second spiral coil conductors 15, 17 are provided. The conductor widths W1 and W3 of the turn portions 16a ₂ , 16a ₃ , 16b ₂ , 16b ₃ , 18a ₂ , 18a ₃ , 18b ₃ , 18b ₃ other than the outermost turn portions 16a ₁ , 16b ₁ , 18a ₁ , 18b ₁ The conductor widths W2 and W4 are set larger. Thereby, the direct current resistance can be lowered while suppressing the overall size of the first and second spiral coil conductors 15 and 17 (conductor patterns 16a, 16b, 18a and 18b) from being increased. As a result, in the multilayer filter MF1, the direct current resistance can be reduced while downsizing the parts. In the multilayer filter MF1, since the direct current resistance is reduced, it is possible to flow a large current and to suppress heat generation when a current is passed.

  In the present embodiment, the relative permeability of the magnetic layer 13 (the plurality of layers 14a and 14b) is in the range of 35 to 120, the resonance frequency of the coil portion is in the range of 470 to 770 MHz, and the resonance of the capacitance generating portion is performed. Since the frequency is in the range of 0.8 to 2.3 GHz and the cut-off frequency for normal mode noise is 100 MHz or more, the multilayer filter MF1 having an attenuation characteristic suitable for a communication terminal such as a mobile phone that supports one-segment broadcasting. Can be realized.

  In the present embodiment, the coil portion 10 includes a nonmagnetic layer 11 and a magnetic layer 13 disposed so as to sandwich at least the nonmagnetic layer 11, and the first and second spiral coils. Since the conductors 15 and 17 are disposed in the non-magnetic layer 11, there is no problem in that the DC resistance of the spiral coil conductor increases, the cost of the multilayer filter increases, and the outer dimensions increase. It becomes possible to set a high value. In addition, since the first and second spiral coil conductors 15 and 17 are not in contact with the magnetic layer 13, eddy current loss generated in the coil portion 10 can be reduced.

  In the present embodiment, the coil unit 10 has a plurality of pairs of first and second spiral coil conductors 15 and 17, and the capacitance generation unit 20 has a plurality of pairs of internal electrodes 23, 25, and 27. ing. In this case, the multilayer filter MF1 can be arrayed.

  In the multilayer filter according to the modification of the present embodiment, the relative permeability of the magnetic layer 13 is in the range of 380 to 755, the resonance frequency of the coil unit 10 is in the range of 174 to 245 MHz, and the capacitance generating unit 20 The resonance frequency may be in the range of 0.8 to 2.3 GHz, and the cutoff frequency for normal mode noise may be 100 MHz or more. In this case, a multilayer filter having attenuation characteristics suitable for a communication terminal such as a mobile phone compatible with terrestrial digital media broadcasting can be realized.

  As a multilayer filter according to a modification of the present embodiment, as shown in FIG. 9, a magnetic layer 13 is disposed inside the first and second spiral coil conductors 15 and 17, and a nonmagnetic material is used. You may arrange | position so that the layer 11 may be covered. As a modification, the magnetic layer 13 may be disposed inside the first and second spiral coil conductors 15 and 17 without covering the nonmagnetic layer 11, and the magnetic layer 13 May be arranged so as to cover the nonmagnetic layer 11 without being arranged inside the first and second spiral coil conductors 15, 17.

  As a multilayer filter according to a modification of the present embodiment, the functional layer 21 (the plurality of layers 22a to 22i) of the capacitance generation unit 20 may be made of a ceramic material mainly composed of ZnO. This ceramic material may contain Pr, Bi, Co, Al or the like as an additive component. When Co is contained in addition to Pr, it has excellent varistor characteristics and also has a high dielectric constant (ε). Further, when Al is further contained, the resistance becomes low. Moreover, other additives, for example, elements such as Cr, Ca, Si, and K may be included as necessary.

  The preferred embodiments of the present invention have been described above. However, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  The shape of the number of turns of the first and second spiral coil conductors 15 and 17 (conductor patterns 16a, 16b, 18a, and 18b) is not limited to that of the above-described embodiment. For example, the number of turns of the conductor patterns 16a, 16b, 18a, 18b may be two turns, or may be four turns or more.

  Each of the laminated conductor patterns 16a, 16b, 18a, and 18b is formed in a spiral shape, but is not limited to this, and at least one of the laminated conductor patterns 16a, 16b, 18a, and 18b is formed. (For example, the conductor patterns 16b and 18b) may be formed in a spiral shape.

The conductor width of the central turn portions 16a ₂ , 16b ₂ , 18a ₂ , 18b ₃ may be different from the conductor width of the innermost turn portions 16a ₃ , 16b ₃ , 18a ₃ , 18b ₃ .

  The number of layers 12a to 12f, 14a, 14b, 22a to 22i, 31 and the shape and number of layers of the first to third internal electrodes 23, 25, 27 are limited to those of the above-described embodiment. Absent.

It is a perspective view of the multilayer filter concerning this embodiment. It is a disassembled perspective view of the element body which comprises the laminated filter which concerns on this embodiment. It is a schematic diagram which shows the cross-sectional structure of the element | base_body which comprises the multilayer filter which concerns on this embodiment. It is a top view which shows the conductor pattern of a 1st spiral coil conductor. It is a top view which shows the conductor pattern of a 2nd spiral coil conductor. It is a figure which shows the equivalent circuit of the multilayer filter which concerns on this embodiment. It is a diagram which shows the attenuation characteristic of the multilayer filter which concerns on this embodiment. It is a diagram which shows the attenuation characteristic of the multilayer filter which concerns on this embodiment. It is a disassembled perspective view of the element body which comprises the multilayer filter which concerns on the modification of this embodiment.

Explanation of symbols

1-5 ... first to fifth terminal electrode, 10 ... coil portion, 11 ... nonmagnetic layer, 13 ... magnetic layer, 15 ... first coil conductor, 16a, 16b ... conductor _pattern, 16a 1, 16b ₁ ... turn portion of the outermost, _16a 2, 16b 2 _... central turn portion of, _16a 3, 16b 3 _... turn portion of the innermost, 17 ... second coil conductors, 18a, 18b ... conductor _pattern, 18a 1, 18b ₁ ... turn portion of the outermost, _18a 2, 18b 2 _... central turn portion of, _18a 3, 18b 3 _... turn portion of the innermost, 20 ... capacitance generation portion, 21 ... functional layer, 23 ... first internal electrode, 25 ... 2nd internal electrode, 27 ... 3rd internal electrode, EB1 ... Elementary body, MF1 ... Multilayer filter.

Claims (10)

A multilayer filter having a coil part,
The coil portion is
A non-magnetic layer;
A magnetic layer disposed so as to sandwich at least the non-magnetic layer;
A first and second spiral coil conductors disposed in the non-magnetic layer and magnetically coupled to each other in the non-magnetic layer;
The first and second spiral coil conductors have a plurality of turns, and a conductor width of an outermost turn portion is larger than a conductor width of a turn portion other than the outermost turn portion. Laminated filter. A capacitance generating unit including a functional layer having dielectric characteristics and a plurality of internal electrodes disposed in the functional layer and facing each other;
The relative permeability of the magnetic layer is in the range of 35 to 120;
The resonance frequency of the coil portion is in a range of 470 to 770 MHz;
The resonance frequency of the capacitance generating unit is in the range of 0.8 to 2.3 GHz.
The multilayer filter according to claim 1, wherein a cut-off frequency with respect to normal mode noise is 100 MHz or more. A capacitance generating unit including a functional layer having dielectric characteristics and a plurality of internal electrodes disposed in the functional layer and facing each other;
The relative permeability of the magnetic layer is in the range of 380 to 755,
A resonance frequency of the coil portion is in a range of 174 to 245 MHz;
The resonance frequency of the capacitance generating unit is in the range of 0.8 to 2.3 GHz.
The multilayer filter according to claim 1, wherein a cut-off frequency with respect to normal mode noise is 100 MHz or more.   The multilayer filter according to claim 2 or 3, wherein the functional layer is made of a dielectric material or a varistor material. The plurality of internal electrodes include a first internal electrode, and second and third internal electrodes facing the first internal electrode,
First and second terminal electrodes connected to both ends of the first spiral coil conductor; third and fourth terminal electrodes connected to both ends of the second spiral coil conductor; And a fifth terminal electrode connected to the one internal electrode,
The second internal electrode is connected to the second terminal electrode;
The multilayer filter according to claim 2, wherein the third internal electrode is connected to the fourth terminal electrode. The coil portion has a plurality of pairs of the first and second spiral coil conductors,
The multilayer filter according to any one of claims 2 to 5, wherein the capacitance generation unit includes a plurality of pairs of the plurality of internal electrodes.   7. The first and second spiral coil conductors are configured by electrically connecting a plurality of stacked spiral conductor patterns. The multilayer filter according to item.   The multilayer filter according to any one of claims 1 to 7, wherein the magnetic layer is disposed inside the first and second spiral coil conductors.   The multilayer filter according to claim 1, wherein the magnetic layer is disposed so as to cover the nonmagnetic layer. A multilayer filter having a coil part,
The coil portion is
A non-magnetic layer;
A first and second spiral coil conductors disposed in the non-magnetic layer and magnetically coupled to each other in the non-magnetic layer;
The first and second spiral coil conductors have a plurality of turns, and a conductor width of an outermost turn portion is larger than a conductor width of a turn portion other than the outermost turn portion. Laminated filter.

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