JP2016106445A - Lc filter elemental body and lc filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the design cost of more than one kind of LC filters differing from each other in the property of attenuation by a trap circuit.SOLUTION: An LC filter elemental body 100 of the present invention comprises: a ceramic laminate 10 arranged by laminating ceramic layers 11, 21, 31, 41 and 51; an LC filter circuit formed in the ceramic laminate 10; and an input terminal IN, an output terminal OUT and a ground terminal GND which are formed on the surface of the ceramic laminate 10. In the LC filter elemental body, trap circuits are connected to the LC filter circuit; and mounting electrodes 54a-54d for mounting external surface mount parts 91 and 92 used as at least part of inductors and capacitors included in the trap circuits are formed on the surface of the ceramic laminate 10. An LC filter is formed by mounting the external surface mount parts 91 and 92 on the mounting electrodes 54a-54d.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an LC filter element body including a ceramic laminate and an LC filter for realizing an LC filter circuit to which a trap circuit is connected.

  Conventionally, in electronic devices such as mobile communication devices, LC filters have been widely used as electronic components that allow signals in a specific frequency band to pass. A small LC filter is realized by configuring an LC filter circuit with a ceramic laminate formed by laminating an electrode pattern and a ceramic layer.

  In the LC filter provided with the above ceramic laminate, it is required to have various pass characteristics and attenuation characteristics depending on the application. In particular, the attenuation characteristic is often changed in order to realize a variation of a specification with a similar characteristic.

  As one method for designing the attenuation characteristic of the LC filter, for example, as shown in Patent Document 1 (Japanese Patent No. 3702767), a trap circuit is built in the LC filter circuit, and the attenuation characteristic of the trap circuit (trap frequency, attenuation amount, etc.) ) There is a way to change. While changing the pass characteristic requires not only changing the frequency but also adjusting the return loss, it is not easy, but the attenuation characteristic of the trap circuit can be changed relatively easily.

Japanese Patent No. 3702767

  However, in the conventional LC filter as disclosed in Patent Document 1, in order to change the attenuation characteristic of the trap circuit, the electrode pattern inside the ceramic laminate constituting the trap circuit is changed for each LC filter. Therefore, there is a problem that the design cost of the LC filter becomes high.

  An object of the present invention is to reduce the design cost of a plurality of types of LC filters having different attenuation characteristics due to a trap circuit.

  The present invention is directed to an LC filter element body and an LC filter using the LC filter element body.

  The LC filter element body of the present invention includes a ceramic laminate in which a plurality of ceramic layers are laminated, an LC filter circuit formed in the ceramic laminate, and an input terminal formed on the surface of the ceramic laminate. A trap circuit connected to the LC filter circuit, and an external surface mount component used as at least a part of an inductor and a capacitor constituting the trap circuit. The mounting electrode is formed on the surface of the ceramic laminate.

  The LC filter of the present invention is characterized in that the external surface mount component is mounted on the mounting electrode of the LC filter element body.

  Further, another LC filter element body of the present invention is formed on a ceramic laminate in which a plurality of ceramic layers are laminated, an LC filter circuit formed inside the ceramic laminate, and a surface of the ceramic laminate. And an input terminal, an output terminal, and a ground terminal. The LC filter element is mounted on a substrate for use, and a trap circuit is connected to the LC filter circuit to form the trap circuit. A part of the inductor and the capacitor are formed inside the ceramic laminate, and constitute the trap circuit. The remaining external inductor mounted on the substrate and not formed in the ceramic laminate, and A relay electrode for electrically connecting to at least one of the capacitors is formed on the surface of the ceramic laminate. It is a symptom.

  Another LC filter of the present invention includes a substrate, the LC filter element body mounted on the substrate, and at least one of the external inductor and capacitor mounted on the substrate, and the relay electrode And at least one of the external inductor and the capacitor is electrically connected, at least one of the external inductor and the capacitor, and the inductor and a part of the capacitor formed inside the ceramic laminate. Thus, the trap circuit is configured.

  According to the present invention, the LC filter having various attenuation characteristics by the trap circuit can be obtained only by selecting the type of the surface-mounted component that becomes a part of the trap circuit described above. Cost can be reduced. That is, various types of LC filters can be designed only by designing a predetermined LC filter element body.

FIG. 1A is an exploded perspective view of the LC filter element body 100 according to the first embodiment of the present invention. FIG. 1B is an external perspective view of the LC filter element body 100 according to the first embodiment of the present invention. FIG. 2 is an equivalent circuit of the LC filter element body 100 according to the first embodiment of the present invention. FIG. 3 is an external perspective view of the LC filter 1100 according to the first embodiment of the present invention. FIG. 4 is an equivalent circuit of the LC filter 1100 according to the first embodiment of the present invention. FIG. 5 is a graph showing pass characteristics of the LC filter 1100 according to the first embodiment of the present invention. FIG. 6A is an exploded perspective view of an LC filter element body 200 according to the second embodiment of the present invention. FIG. 6B is an external perspective view of the LC filter element body 200 according to the second embodiment of the present invention. FIG. 7 is an equivalent circuit of an LC filter element body 200 according to the second embodiment of the present invention. FIG. 8 is an external perspective view of an LC filter 1200 according to the second embodiment of the present invention. FIG. 9 is an equivalent circuit of the LC filter 1200 according to the second embodiment of the present invention. FIG. 10 is a graph showing pass characteristics of the LC filter 1200 according to the second embodiment of the present invention.

(First embodiment)
A first embodiment of the present invention will be described below with reference to the drawings.

  1A, 1B, and 2 show an LC filter element body 100 according to a first embodiment of the present invention. 1A is an exploded perspective view of the LC filter element body 100, FIG. 1B is an external perspective view of the LC filter element body 100, and FIG. 2 is an equivalent circuit of the LC filter element body 100. Is shown.

  3 and 4 show an LC filter 1100 according to the first embodiment of the present invention. 3 shows an external perspective view of the LC filter 1100, and FIG. 4 shows an equivalent circuit of the LC filter 1100.

  As will be described later, the LC filter 1100 is configured by mounting surface-mounted components on the mounting electrodes of the LC filter element body 100. The LC filter 1100 is a band pass filter.

  As shown in FIG. 1A, the LC filter element body 100 includes a ceramic laminated body 10 including a plurality of ceramic layers. Although the material of the ceramic laminated body 10 is not specifically limited, For example, barium titanate can be used.

  The ceramic laminate 10 has a structure in which five ceramic layers 11, 21, 31, 41, 51 are laminated in order from the bottom.

  A rectangular internal electrode 12 is formed on the surface of the ceramic layer 11. The internal electrode 12 is drawn out of the laminated body 10 from two opposing long sides of the ceramic layer 11.

  Two rectangular internal electrodes 22 a and 22 b are formed on the surface of the ceramic layer 21. Further, two via electrodes 23 a and 23 b are formed through the ceramic layer 21. The via electrodes 23a and 23b are electrically connected to the internal electrode 12, respectively.

  Two internal electrodes 32 a and 32 b are formed on the surface of the ceramic layer 31. The two internal electrodes 32 a and 32 b are each drawn out of the laminated body 10 from two opposing short sides of the ceramic layer 31. Further, six via electrodes 33a, 33b, 33c, 33d, 33e, and 33f are formed through the ceramic layer 31. The via electrode 33a is electrically connected to the via electrode 23a. The via electrode 33b is electrically connected to the via electrode 23b. The via electrodes 33c and 33d are electrically connected to the internal electrode 22b. The via electrodes 33e and 33f are electrically connected to the internal electrode 22a.

  Two rectangular internal electrodes 42 a and 42 b are formed on the surface of the ceramic layer 41. Further, eight via electrodes 43a, 43b, 43c, 43d, 43e, 43f, 43g, and 43h are formed through the ceramic layer 41. The via electrode 43a is electrically connected to the internal electrode 32a. One end of the via electrode 43b is electrically connected to the internal electrode 42a, and the other end is electrically connected to the via electrode 33a. One end of the via electrode 43c is electrically connected to the internal electrode 42b, and the other end is electrically connected to the via electrode 33b. One end of the via electrode 43d is electrically connected to the internal electrode 32b. One end of the via electrode 43e is electrically connected to the via electrode 33c. One end of the via electrode 43f is electrically connected to the other end of the internal electrode 42b, and the other end is electrically connected to the via electrode 33d. One end of the via electrode 43g is electrically connected to the other end of the internal electrode 42a, and the other end is electrically connected to the via electrode 33e. The via electrode 43h is electrically connected to the via electrode 33f.

  Four rectangular mounting electrodes 54 a, 54 b, 54 c, 54 d are formed on the surface of the ceramic layer 51. Further, four via electrodes 53a, 53b, 53c, and 53d are formed through the ceramic layer 51. One end of the via electrode 53a is electrically connected to the via electrode 43a, and the other end is electrically connected to the mounting electrode 54a. One end of the via electrode 53b is electrically connected to the via electrode 43d, and the other end is electrically connected to the mounting electrode 54b. One end of the via electrode 53c is electrically connected to the via electrode 43e, and the other end is electrically connected to the mounting electrode 54c. One end of the via electrode 53d is electrically connected to the via electrode 43h, and the other end is electrically connected to the mounting electrode 54d.

  As shown in FIG. 1B, an input terminal IN and an output terminal OUT are formed on the opposing short side surface of the ceramic laminate 10. However, the input terminal IN is hidden in the ceramic laminate 10 and is not shown. The input terminal IN is connected to the internal electrode 32a, and the output terminal OUT is connected to the internal electrode 32b.

  A pair of ground terminals GND is formed on the side surface of the ceramic laminate 10 on the opposite long side. However, one of the pair of ground terminals GND is hidden in the ceramic laminate 10 and is not shown. The pair of ground terminals GND are connected to the internal electrode 12, respectively.

  Internal electrodes 12, 22a, 22b, 32a, 32b, 42a, 42b, via electrodes 23a, 23b, 33a-33f, 43a-43h, 53a-53d, mounting electrodes 54a-54d, input terminal IN, output terminal OUT, ground The material of the terminal GND is not particularly limited, but for example, a conductor paste containing Cu can be used.

  The LC filter element body 100 having the above structure includes an equivalent circuit shown in FIG.

  In the LC filter element body 100, an LC resonance circuit Q1 in which an inductor L7 and a capacitor C3 are connected in parallel is inserted between an input terminal IN and a ground terminal GND. The inductor L7 is mainly formed by a loop-shaped path from the internal electrode 22a to the internal electrode 12 via the via electrode 33e, the via electrode 43g, the internal electrode 42a, the via electrode 43b, the via electrode 33a, and the via electrode 23a. Has been. The capacitor C3 mainly includes a capacitance formed between the internal electrode 22a and the internal electrode 12 with the ceramic layer 21 interposed therebetween.

  An LC resonance circuit Q2 in which an inductor L8 and a capacitor C4 are connected in parallel is inserted between the output terminal OUT and the ground terminal GND. The inductor L8 is mainly formed by a path from the internal electrode 22b to the internal electrode 12 via the via electrode 33d, the via electrode 43f, the internal electrode 42b, the via electrode 43c, the via electrode 33b, and the via electrode 23b. . The capacitor C4 mainly includes a capacitance formed between the internal electrode 22b and the internal electrode 12 with the ceramic layer 21 interposed therebetween.

  A mutual inductance M is formed between the inductor L7 and the inductor L8, and the LC resonance circuit Q1 and the LC resonance circuit Q2 are electromagnetically coupled.

  A capacitor C1 and inductors L1 and L3 constituting a part of the trap circuit are connected between the input terminal IN and the LC resonance circuit Q1. The capacitor C1 is mainly composed of a capacitance formed between the internal electrode 22a and the internal electrode 32a with the ceramic layer 31 interposed therebetween. The inductor L1 is mainly formed by a path from the internal electrode 32a to the mounting electrode 54a via the via electrode 43a and the via electrode 53a. The inductor L3 is mainly formed by a path from the mounting electrode 54d to the internal electrode 22a via the via electrode 53d, the via electrode 43h, and the via electrode 33f.

  A capacitor C2 and inductors L4 and L6 constituting a part of the trap circuit are connected between the output terminal OUT and the LC resonance circuit Q2. The capacitor C2 is mainly composed of a capacitance formed between the internal electrode 22b and the internal electrode 32b with the ceramic layer 31 interposed therebetween. The inductor L4 is mainly formed by a path from the mounting electrode 54c to the internal electrode 22b via the via electrode 53c, the via electrode 43e, and the via electrode 33c. The inductor L6 is mainly formed by a path from the internal electrode 32b to the mounting electrode 54b via the via electrode 43d and the via electrode 53b.

  The mounting electrode 54a that is one end of the inductor L1 and the mounting electrode 54d that is one end of the inductor L3 are open ends. Similarly, the mounting electrode 54c which is one end of the inductor L4 and the mounting electrode 54b which is one end of the inductor L6 are open ends.

  Next, a method for configuring the LC filter 1100 by mounting an external surface mount component on the mounting electrode of the LC filter element body 100 described above will be described.

  The external surface mount component 91 is a chip inductor in which terminal electrodes 91a and 91b are formed at both ends. The external surface mount component 92 is a chip inductor having terminal electrodes 91c and 91d formed at both ends.

  As shown in FIG. 3, an external surface mounting component 91 is mounted on the mounting electrodes 54 a and 54 d of the LC filter element body 100. Further, as shown in FIG. 3, an external surface mounting component 92 is mounted on the mounting electrodes 54b and 54c. The terminal electrodes 91a and 91b at both ends of the surface mount component 91 are soldered to the mounting electrodes 54a and 54d, respectively. Further, the terminal electrodes 92c and 92d at both ends of the surface mounting component 92 are soldered to the mounting electrodes 54b and 54c, respectively. However, in FIG. 3, detailed illustration of the joint portion is omitted.

  As a result of the above mounting, as shown in FIG. 4, the LC filter circuit includes a trap circuit T1 including inductors L1, L2, L3 and a capacitor C1, and a trap circuit T2 including inductors L4, L5, L6 and a capacitor C2. Will be connected. By selecting the chip inductors 91 and 92 having different inductances, the attenuation characteristics of the trap circuits T1 and T2 can be adjusted.

  According to the present invention, the LC filter having various attenuation characteristics by the trap circuit can be obtained only by selecting the type of the surface-mounted component that becomes a part of the trap circuit described above. Cost can be reduced. That is, various types of LC filters can be designed only by designing a predetermined LC filter element body.

  In this embodiment, chip inductors are used for the surface mount components 91 and 92. However, the attenuation characteristics of the trap circuits T1 and T2 may be adjusted using chip capacitors for the surface mount components 91 and 92.

  Next, an example of a method for manufacturing the LC filter element body 100 according to the first embodiment of the present invention will be described.

  First, a ceramic green sheet for forming the ceramic layers 11, 21, 31, 41, 51 is prepared. The ceramic green sheet can be produced by a known method that has been widely used in the production process of ceramic multilayer electronic components.

  Next, holes for forming the via electrodes 23a, 23b, 33a to 33f, 43a to 43h, and 53a to 53d are formed in the ceramic green sheet. The holes can be formed by punching, laser light irradiation, or the like.

  Next, a conductive paste is applied to the surface of the ceramic green sheet in a desired shape to form the internal electrodes 12, 22a, 22b, 32a, 32b, 42a, 42b and the mounting electrodes 54a to 54d. At the same time, the holes for forming the via electrodes are filled with the conductive paste to form the via electrodes 23a, 23b, 33a to 33f, 43a to 43h, and 53a to 53d.

  Next, in order from the bottom, ceramic green sheets are laminated and pressure-bonded to produce an unfired ceramic laminate 10.

  Next, a conductive paste is applied in a predetermined shape on the surface of the ceramic laminate 10 to form the input terminal IN, the output terminal OUT, and the ground terminal GND.

  Next, the unfired ceramic laminate 10 is fired with a predetermined profile to produce the ceramic laminate 10.

  With this method, the LC filter element body 100 according to the first embodiment of the present invention is completed.

First experimental example

  In order to confirm the effectiveness of the present invention, the following simulation experiment was performed.

  First, assuming the LC filter 1100 according to the first embodiment of the present invention described above, the pass characteristic was simulated as Experimental Example 1. Next, assuming the LC filter 1100 in which only the inductance values of the surface-mounted component 91 (chip inductor) and the surface-mounted component 92 (chip inductor) in Experimental Example 1 are changed, passing characteristics are simulated as Experimental Example 2. .

  FIG. 5 shows the pass characteristics of the LC filter 1100 obtained by the above simulation. The solid line corresponds to the pass characteristic of Experimental Example 1, and the broken line corresponds to the pass characteristic of Experimental Example 2.

  As can be seen from FIG. 5, Experimental Example 1 and Experimental Example 2 each have two attenuation poles due to the trap circuits T <b> 1 and T <b> 2 in the vicinity of 5 GHz, which is on the higher frequency side than the passband. Further, comparing Experimental Example 1 and Experimental Example 2, it is possible to change the frequencies of the two attenuation poles by the trap circuits T1 and T2 by mounting the surface mounting components 91 and 92 having different inductance components. I understand that.

  In the experimental example, two types of LC filters were produced, but by further increasing the types of surface-mounted components to be mounted, more types of LC filters can be obtained with less design cost burden.

  The structure of the LC filter element body 100 and the LC filter 1100 according to the first embodiment of the present invention and an example of the manufacturing method thereof have been described above. However, the LC filter element body and the LC filter of the present invention are not limited to these contents, and various modifications can be made in accordance with the spirit of the invention.

  For example, in the LC filter element body 100, a part of the inductor constituting the trap circuit T1 is constituted by the surface mount component 91, and a part of the inductor constituting the trap circuit T2 is constituted by the surface mount component 92. All the inductors constituting the trap circuit may be constituted by surface mount components. That is, the trap circuit main body does not have to be formed inside the ceramic laminate.

Further, the type and structure of the surface mount components 91 and 92 are arbitrary, and may be a multilayer chip inductor or a wound chip inductor.
(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

  FIGS. 6A, 6B, and 7 show an LC filter element body 200 according to the second embodiment of the present invention. 6A is an exploded perspective view of the LC filter element body 200, FIG. 6B is an external perspective view of the LC filter element body 200, and FIG. 7 is an equivalent circuit of the LC filter element body 200. Is shown.

  8 and 9 show an LC filter 1200 according to the second embodiment of the present invention. 8 is an external perspective view of the LC filter 1200, and FIG. 9 is an equivalent circuit of the LC filter 1200.

  As will be described later, the LC filter 1200 is configured by mounting the LC filter element body 200 on a substrate. The LC filter 1200 is a high pass filter.

  As shown in FIG. 6A, the LC filter element body 200 includes a ceramic laminate 10 composed of a plurality of ceramic layers. The ceramic laminate 10 has a structure in which eight ceramic layers 11, 21, 31, 41, 51, 61, 71, 81 are laminated in order from the bottom.

  A rectangular internal electrode 12 is formed on the surface of the ceramic layer 11. The internal electrode 12 is drawn out of the laminated body 10 from two opposing long sides of the ceramic layer 11.

  Two rectangular internal electrodes 22 a and 22 b are formed on the surface of the ceramic layer 21. Each of the internal electrodes 22 a and 22 b is led out of the ceramic laminate 10 from one long side of the ceramic layer 21.

  Two rectangular internal electrodes 32 a and 32 b and a jump coupling electrode 35 are formed on the surface of the ceramic layer 31. Each of the internal electrodes 32 a and 32 b is led out of the ceramic laminated body 10 from two opposing short sides of the ceramic layer 31. Further, two via electrodes 33a and 33b are formed through the ceramic layer 31. The via electrode 33a is electrically connected to the internal electrode 22a. The via electrode 33b is electrically connected to the internal electrode 22b.

  On the surface of the ceramic layer 41, two H-shaped internal electrodes 42a and 42b are formed. Further, two via electrodes 43c and 43d are formed through the ceramic layer 41. The via electrode 43c is electrically connected to the via electrode 33b. The via electrode 43d is electrically connected to the via electrode 33a.

  Two U-shaped internal electrodes 52 a and 52 b are formed on the surface of the ceramic layer 51. Further, four via electrodes 53a, 53b, 53c, and 53d are formed through the ceramic layer 51. One end of the via electrode 53a is electrically connected to one end of the internal electrode 42a, and the other end is electrically connected to one end of the internal electrode 52a. One end of the via electrode 53b is electrically connected to one end of the internal electrode 42b, and the other end is electrically connected to one end of the internal electrode 52b. The via electrode 53c is electrically connected to the via electrode 43c. The via electrode 53d is electrically connected to the via electrode 43d.

  Two U-shaped internal electrodes 62 a and 62 b are formed on the surface of the ceramic layer 61. Further, four via electrodes 63a, 63b, 63c, and 63d are formed through the ceramic layer 61. One end of the via electrode 63a is electrically connected to one end of the internal electrode 52a, and the other end is electrically connected to one end of the internal electrode 62a. One end of the via electrode 63b is electrically connected to one end of the internal electrode 52b, and the other end is electrically connected to one end of the internal electrode 62b. The via electrode 63c is electrically connected to the via electrode 53c. The via electrode 63d is electrically connected to the via electrode 53d.

  Two U-shaped internal electrodes 72 a and 72 b are formed on the surface of the ceramic layer 71. Further, four via electrodes 73a, 73b, 73c, and 73d are formed through the ceramic layer 71. One end of the via electrode 73a is electrically connected to one end of the internal electrode 62a, and the other end is electrically connected to one end of the internal electrode 72a. One end of the via electrode 73b is electrically connected to one end of the via electrode 63d, and the other end is electrically connected to one end of the internal electrode 72a. One end of the via electrode 73c is electrically connected to the via electrode 63c, and the other end is electrically connected to one end of the internal electrode 72b. One end of the via electrode 73d is electrically connected to one end of the internal electrode 62b, and the other end is electrically connected to one end of the internal electrode 72b.

  A rectangular identification mark D is formed on the surface of the ceramic layer 81.

  As shown in FIG. 6B, an input terminal IN and an output terminal OUT are formed on the opposing side surfaces of the ceramic laminate 10. However, the input terminal IN is hidden in the ceramic laminate 10 and is not shown. The input terminal IN is connected to the internal electrode 32a. The output terminal OUT is connected to the internal electrode 32b.

  A pair of ground terminals GND is formed on another opposing side surface of the ceramic laminate 10. However, one of the pair of ground terminals GND is hidden in the ceramic laminate 10 and is not shown. The pair of ground terminals GND are connected to the internal electrode 12, respectively.

  Two relay electrodes N1 and N2 are formed on one of the opposing side surfaces of the ceramic laminate 10. The relay electrode N1 is connected to the internal electrode 22a. The relay electrode N2 is connected to the internal electrode 22b.

  The LC filter element body 200 having the above structure includes an equivalent circuit shown in FIG.

  In the LC filter element body 200, three capacitors C1, C2, and C3 are inserted in series between the input terminal IN and the output terminal OUT. The capacitor C1 mainly includes a capacitance formed between the internal electrode 32a and one end of the internal electrode 42a with the ceramic layer 41 interposed therebetween. The capacitor C2 mainly includes a capacitance formed by a path from one end of the internal electrode 42a to the one end of the internal electrode 42b via the jump coupling electrode 35. The capacitor C3 mainly includes a capacitance formed between one end of the internal electrode 42b and the internal electrode 32b with the ceramic layer 41 interposed therebetween.

  A part of the trap circuit in which the inductor L1 and the capacitor C5 are connected in series is inserted between the connection point between the capacitor C1 and the capacitor C2 and the ground terminal GND. The inductor L1 mainly includes the internal electrode 42a, the via electrode 53a, the internal electrode 52a, the via electrode 63a, the internal electrode 62a, the via electrode 73a, the internal electrode 72a, the via electrode 73b, the via electrode 63d, the via electrode 53d, and the via electrode. 43d and a path reaching the internal electrode 22a via the via electrode 33a. The capacitor C5 mainly includes a capacitance formed between the internal electrode 22a and the internal electrode 12 with the ceramic layer 21 interposed therebetween.

  Similarly, a part of the trap circuit in which the inductor L2 and the capacitor C6 are connected in series is inserted between the connection point between the capacitor C2 and the capacitor C3 and the ground terminal GND.

  A gap between the inductor L1 and the ground terminal GND is an open end due to the relay electrode N1 and the internal electrode 12. Further, the relay electrode N2 and the internal electrode 12 form an open end between the inductor L2 and the ground terminal GND.

  The LC filter element body 200 having the above structure is used as an LC filter by the following method, for example. First, the LC filter element 200 is mounted on the substrate 1 having the electrode pattern 2 formed on the surface thereof by soldering. Next, two external surface mount components 91 and 92 (chip capacitors) are mounted on the substrate 1 by soldering as shown in FIG. By this mounting, one of the terminal electrodes 91a of the surface mount component 91 is connected to the relay electrode N1, and the other terminal electrode 91b is connected to the ground terminal GND. One terminal electrode 92a of the surface mount component 92 is connected to the relay electrode N2, and the other terminal electrode 92b is connected to the ground terminal GND, whereby the LC filter 1200 is completed. However, illustration of solder is omitted in FIG. In addition, as the board | substrate 1, a general printed circuit board may be used and the board | substrate formed by laminating | stacking a ceramic layer may be used.

  As a result of the above mounting, as shown in FIG. 9, the LC filter circuit is connected to a trap circuit T1 including an inductor L1 and capacitors C4 and C5, and a trap circuit T2 including an inductor L3 and capacitors C6 and C7. It will be.

Even in the above case, according to the second embodiment, various attenuation characteristics by the trap circuit can be selected just by selecting the type of the surface-mounted component to be connected as a part of the trap circuit, as in the first embodiment. Therefore, the LC filter design cost can be reduced.
In addition, when the LC filter element body is mounted on the substrate, the attenuation characteristics of the trap circuit in the LC filter element body may fluctuate due to the variation in the amount of solder and the influence of the electrode pattern formed on the substrate surface. However, according to the LC filter 1200 of the second embodiment, with the LC filter element body 200 mounted on the substrate 1, an external connection that becomes a part of the trap circuits T1 and T2 while checking the variation of the attenuation characteristic is confirmed. The type of surface mount component can be selected. As a result, the characteristics of the trap circuit can be easily adjusted to an appropriate one.

  Since the manufacturing method of the LC filter element body 200 is the same as the manufacturing method of the LC filter element body 100 according to the first embodiment, the description thereof is omitted.

Second experiment example

  In order to confirm the effectiveness of the present invention, an experiment by simulation of the pass characteristics was performed on the LC filter 1200 of the second embodiment, as in the first embodiment.

  First, assuming the LC filter 1200 according to the second embodiment of the present invention described above, the pass characteristic was simulated as Experimental Example 3. Next, assuming the LC filter 1200 in which only the capacitance values of the surface-mounted component 91 (chip capacitor) and the surface-mounted component 92 (chip capacitor) in Experimental Example 3 were changed, the passing characteristics were simulated as Experimental Example 4. .

  FIG. 10 shows the pass characteristics of the LC filter 1200 obtained by the above simulation. The solid line corresponds to the pass characteristic of Experimental Example 3, and the broken line corresponds to the pass characteristic of Experimental Example 4.

  As can be seen from FIG. 10, Experimental Example 3 and Experimental Example 4 each have two attenuation poles formed by trap circuits T <b> 1 and T <b> 2 in the vicinity of 1 GHz on the lower frequency side than the passband. Further, comparing Experimental Example 3 and Experimental Example 4, it can be seen that the frequency of the two attenuation poles by the trap circuits T1 and T2 can be changed by mounting surface-mounted components having different capacitance values. .

  The structure of the LC filter element body 200 and the LC filter 1200 according to the second embodiment of the present invention and the example of the manufacturing method thereof have been described above. However, the LC filter element body and the LC filter of the present invention are not limited to these contents, and various modifications can be made in accordance with the spirit of the invention.

  For example, in the LC filter element body 200, surface mounted components are used as external capacitors, but lead type capacitors may be used.

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Electrode pattern 10 Ceramic laminated body 11, 21, 31, 41, 51, 61, 71, 81 Ceramic layers 12, 22a, 22b, 32a, 32b, 42 Internal electrodes 23a, 23b, 33a-33f, 43a-43h , 53a to 53d, 63a to 63d, 73a to 73d Via electrode 35 Jump coupling electrodes 54a to 54d Mounting electrodes 91 and 92 Surface mount component (chip inductor or chip capacitor)
91a, 91b, 92a, 92b Terminal electrode IN Input terminal OUT Output terminal GND Ground terminal D Identification mark N1, N2 Relay electrode 100, 200 LC filter element body 1100, 1200 LC filter M Mutual inductance L1, L2, L3, L4, L5 , L6 Inductors C1, C2, C3, C4, C5, C6, C7 Capacitors T1, T2 Trap circuit Q1, Q2 LC resonance circuit

Claims (5)

A ceramic laminate in which a plurality of ceramic layers are laminated;
An LC filter circuit formed inside the ceramic laminate;
An input terminal formed on the surface of the ceramic laminate, an output terminal, and a ground terminal;
A trap circuit is connected to the LC filter circuit;
A mounting electrode for mounting an external surface mounting component used as at least part of an inductor and a capacitor constituting the trap circuit is formed on the surface of the ceramic laminate. Filter body.   2. The LC filter element body according to claim 1, wherein an inductor or a capacitor other than the external surface mount component that constitutes the trap circuit is formed in the ceramic multilayer body.   3. The LC filter, wherein the external surface mount component is mounted on the mounting electrode of the LC filter element body according to claim 1 or 2. A ceramic laminate in which a plurality of ceramic layers are laminated;
An LC filter circuit formed inside the ceramic laminate;
An input terminal formed on the surface of the ceramic laminate, an output terminal, and a ground terminal;
An LC filter element for mounting on a substrate for use,
A trap circuit is connected to the LC filter circuit;
A part of the inductor and the capacitor constituting the trap circuit is formed inside the ceramic laminate,
A relay electrode for electrically connecting to at least one of an external inductor and a capacitor mounted on the substrate, which is not formed in the ceramic laminate, and constitutes the trap circuit, An LC filter element body formed on the surface of a laminate. A substrate,
The LC filter element body according to claim 4, mounted on the substrate,
And at least one of the external inductor and capacitor mounted on the substrate,
At least one of the external inductor and capacitor is electrically connected to the relay electrode,
The LC filter, wherein the trap circuit is constituted by at least one of the external inductor and capacitor and a part of the inductor and capacitor formed in the ceramic laminate.