JP2006222607A - Filter element and electronic module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter element that can easily be made high frequency and downsized, and cope with multiband applications, and to provide an electronic module. <P>SOLUTION: The filter element includes: a plurality of dielectric ceramic layers 1b to 1i formed respectively on them with coil forming conductors 2b to 2h; a dielectric ceramic layer 1a formed thereon with a GND conductor 3a; and capacitance forming conductors 4a to 4c not connected to the coil forming conductors 2b to 2h nor a GND conductor 3 and formed to part or all of the dielectric ceramic layers 1b, 1d, 1f, wherein a second capacitance forming conductor 7a is formed on the dielectric ceramic layer 1b via the GND conductor 3 and the capacitance forming conductor 4a and the second capacitance forming conductor 7a are connected by an inductance forming conductor 7b, the coil forming conductors 2b to 2h and the first capacitance forming conductors 4a to 4c configure a first capacitance, and the second capacitance forming conductor 7a and the GND conductor 3 configure a second capacitance. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a filter element and an electronic module, particularly a filter element used for noise removal, etc., and is specified by utilizing parallel resonance or series resonance of inductance and capacitance formed by a conductor pattern in a laminated insulator. The present invention relates to a filter element and an electronic module capable of obtaining a steep attenuation amount at a frequency.

  Conventionally, when coil pieces are formed on a plurality of insulator layers and each insulator layer is laminated, the coil pieces are connected to form a circular coil, and this coil and the insulator layer are formed. An example in which a multilayer filter element is realized by using a capacitor formed between conductive patterns is known.

  As this multilayer filter element, an element that actively utilizes distributed constant capacitance between element internal circuits has been proposed (for example, see Patent Document 1). In this filter element, a double coil is formed in the element, and a capacitor is configured by using a distributed constant capacitance formed between the coils.

If the two coils of the filter element are referred to as a coil L1 and a coil L2, as shown in FIG. 8, a signal input terminal and an output terminal are provided at both ends of the coil L1, and the coil L2 is connected to the ground. Using the distributed constant capacitance between the coil L1 and the coil L2 and the inductance of the coil L1 and the coil L2, a low-pass filter element that can obtain a steep attenuation at a specific frequency can be configured.
Japanese Patent Laid-Open No. 04-2108

  In the conventional filter element using the two coils and the distributed constant capacitance between them, it is necessary to form two coils. Therefore, in order to reduce the size, each coil is made smaller and the area occupied by each coil is made smaller. There is a need to. However, if the coil is made smaller, if the processing accuracy is reduced even a little, the distributed constant capacity between the coils changes, and there is a problem that a desired filter characteristic cannot be obtained. That is, the demand for processing accuracy becomes severe.

  In addition, in order to obtain a steep attenuation at a specific frequency, it is not known what configuration of capacitance and inductance is good, which has been a big design problem. In particular, the control of the attenuation in the graph in which the horizontal axis represents frequency and the vertical axis represents attenuation is an important point for realizing desired filter characteristics.

  In order to solve this problem, the present inventors formed a first capacitor between the coil forming conductor for forming the coil and the capacitor forming conductor, and between the capacitor forming conductor and the grounding conductor. In addition, a filter element having a steep attenuation characteristic in a transition region between a passband in a low frequency region and a stopband in a high frequency region has been found by forming a second capacitor (Japanese Patent Application No. 2004-22194). .

  On the other hand, in order to cope with the widening and multiband use frequency of electronic devices in recent years, characteristics that can provide sufficient attenuation in a plurality of frequency bands have been demanded.

  However, the filter of Japanese Patent Application No. 2004-22194 has a steep attenuation in the attenuation region and has excellent characteristics. However, there is no attenuation peak in the high frequency region thereafter, and a multiband mobile phone or the like is used. In some cases, the noise suppressing element has insufficient characteristics.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a filter element and an electronic module that can be easily increased in frequency and reduced in size, and can cope with multiband.

  The filter element of the present invention has a plurality of insulating layers formed with coil forming conductors for forming a coil that continuously circulates in a laminated state, and an insulating layer formed with a grounding conductor, A first capacitor forming conductor that is not connected to either the coil forming conductor or the grounding conductor is formed in a part or all of the insulating layer, and the second capacitor forming conductor is interposed via the grounding conductor and the insulating layer. The first capacitance forming conductor and the second capacitance forming conductor are connected by an inductance forming conductor, and the first capacitance-forming conductor is connected between the coil-forming conductor and the first capacitance-type conductor. A second capacitance is formed between the second capacitance forming conductor and the grounding conductor, an inductance is formed by the inductance forming conductor, the circulating coil, the first capacitance, the first capacitance, 2 capacity and induct A filter characteristic is obtained by the inductance of the conductor for forming the transformer.

  In such a filter element, by connecting the first capacitance forming conductor and the second capacitance forming conductor with the inductance forming conductor, a second attenuation peak can be generated on the high frequency side. Desired filter characteristics corresponding to multi-banding can be obtained.

  Here, when the inductance forming conductor, the second capacitance forming conductor, and the first capacitance forming conductor are formed in the same insulating layer, it is not necessary to newly increase the number of stacked layers, and the device can be downsized.

  Furthermore, the filter element of the present invention has a plurality of insulating layers formed with coil forming conductors for forming a coil that continuously circulates in a laminated state, and an insulating layer formed with a grounding conductor. The first capacitor forming conductor that is not connected to either the coil forming conductor or the grounding conductor is formed on a part or all of the insulating layer, and the first capacitor forming conductor is interposed between the first capacitor forming conductor and the insulating layer. A two-capacitance forming conductor is formed, and the grounding conductor and the second capacitance-forming conductor are connected by an inductance-forming conductor, and between the coil-forming conductor and the first capacitance-type conductor. A first capacitor is formed, and a second capacitor is formed between the second capacitor forming conductor and the first capacitor forming conductor. An inductance is formed by an inductance forming conductor, and filter characteristics are obtained by the inductance of the circulating coil, the first capacitor, the second capacitor, and the inductance forming conductor.

  In such a filter element, the second attenuation peak can be generated on the high-frequency side by connecting the grounding conductor and the second capacitance forming conductor with the inductance forming conductor, thereby realizing a wide band and multiband. Desired filter characteristics corresponding to the above can be obtained.

  Here, since the grounding conductor, the inductance forming conductor, and the second capacitance forming conductor are formed in the same insulating layer, it is not necessary to newly increase the number of stacked layers, and the device can be miniaturized.

  The grounding conductor is preferably formed on the uppermost or lowermost insulating layer. The coil forming conductor is preferably composed of a U-shaped or U-shaped coil forming bent conductor and upper and lower layer connecting conductors.

  In such a filter element, since the first capacitor is formed between the coil forming bent conductor and the first capacitor forming conductor, the distributed constant inductance of the coil forming conductor and the first capacitor forming conductor are configured. And a distributed constant capacitance between the coil-forming bent conductors can constitute an LC filter. For this reason, one coil is sufficient and a small element is realizable compared with the structure which requires two coils.

  Further, since the second capacitor is configured between the second capacitor forming conductor and the grounding conductor, and between the first capacitor forming conductor and the second capacitor forming conductor, the pass band and the high frequency region of the low frequency region are formed. In the transition region to the stop band, the attenuation slope of the pass characteristic becomes steep, and a low-pass filter element having excellent characteristics can be realized.

  Furthermore, in the filter element of the present invention, it is preferable that the capacitance forming conductors are respectively formed in the plurality of insulating layers, and the capacitance forming conductors between the insulating layers are connected by via conductors in the insulating layers. Further, it is preferable that the coil forming bent conductor and the upper and lower layer connecting conductors are connected by via conductors in the insulating layer.

  In such a filter element, since it is not necessary to provide a connection conductor on the surface of the element, the surface of the element can be used widely. Therefore, the size of input / output terminals and connection terminals for connection to an external circuit and the distance between them can be increased, and defects such as a short circuit between external terminals can be reduced, and the filter element can be miniaturized.

  An electronic module according to the present invention includes the above-described filter element. Since such an electronic module can be mounted with a small filter having excellent characteristics, the entire electronic module can be reduced in size and improved in characteristics.

  As described above, in the filter element of the present invention, a distributed constant inductance is formed by interlayer connection of coil forming conductors, and a distributed constant capacitance is formed between the coil forming conductor and the capacitance forming conductor. Therefore, the filter element can be downsized because only one coil conductor is required. In addition, since the second capacitor is configured between the second capacitor forming conductor and the grounding conductor, and between the first capacitor forming conductor and the second capacitor forming conductor, In the transition region between the high-frequency region and the stop band, the attenuation of the pass characteristic becomes steep, and a low-pass filter element having excellent characteristics can be realized. Further, the first capacitance forming conductor and the second capacitance forming conductor are connected by the inductance forming conductor, or the grounding conductor and the second capacitance forming conductor are connected by the inductance forming conductor, so that the second Attenuation peaks occur, and it is possible to cope with widening of the filter and multiband.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an external perspective view of the filter element of the present invention. 2 is a cross-sectional view of the filter element taken along line XX, and FIG. 3 is an exploded perspective view of the structure when dielectric ceramic layers are laminated.

  As shown in FIG. 1, the filter element of the present invention includes a ceramic laminate 1 composed of a plurality of dielectric ceramic layers, an input terminal 2a of a signal line formed on the outer surface thereof, an output terminal 2i, It is a chip component composed of terminals 3 of the GND line.

  As shown in FIG. 2, the ceramic laminated body 1 has a nine-layer laminated structure from the lowermost dielectric ceramic layer 1a to the uppermost dielectric ceramic layer 1i. The present invention is not limited to nine layers as long as a plurality of layers are laminated.

  Referring to FIG. 3, the dielectric ceramic layer 1a is provided with a GND conductor (grounding conductor) 3a, and terminals are provided in two directions from the GND conductor 3a, which are connected to the GND terminal 3. Yes.

  The next dielectric ceramic layer 1b includes an elongated straight plate-like coil forming conductor 2b, an elongated straight plate-like first capacitance forming conductor 4a, a second capacitance forming conductor 7a, and a first capacitance formation. An inductance forming conductor 7b that connects the conductor 4a and the second capacitance forming conductor 7a is formed. The plate-like coil forming conductor 2b is formed separately from the other conductors 4a, 7a, and 7b. One end of the coil forming conductor 2b is connected to the input terminal 2a. An S-shaped conductor pattern is formed by the conductors 4a, 7a, and 7b.

  The dielectric ceramic layer 1c is formed with a U-shaped coil forming conductor (corresponding to a coil forming bent conductor) 2c. One end of the coil forming conductor 2c is formed with a coil on the dielectric ceramic layer 1b via a via-hole conductor (shown schematically by a thin line in FIG. 3) 5a provided so as to penetrate the dielectric ceramic layer 1c. The conductor 2b is connected.

  The dielectric ceramic layer 1d is formed with a thin and straight plate-like coil forming conductor (corresponding to upper and lower layer connecting conductors) 2d and a first capacitance forming conductor 4b. One end of the coil forming conductor 2d is connected to the other end of the coil forming conductor 2c on the dielectric ceramic layer 1c through a via-hole conductor 5b provided so as to penetrate the dielectric ceramic layer 1d. The capacitance forming conductor 4b is connected to the first capacitance forming conductor 4a through a via-hole conductor 6a provided so as to penetrate the dielectric ceramic layers 1c and 1d.

  On the dielectric ceramic layer 1e, a U-shaped coil forming conductor (corresponding to a coil forming bent conductor) 2e is formed. One end of the coil forming conductor 2e is connected to the coil forming conductor 2d on the dielectric ceramic layer 1d via a via-hole conductor 5c provided so as to penetrate the dielectric ceramic layer 1e.

  The dielectric ceramic layer 1f is formed with a thin and straight plate-like coil forming conductor (corresponding to upper and lower layer connecting conductors) 2f and a capacitance forming conductor 4c. One end of the coil forming conductor 2f is connected to the other end of the coil forming conductor 2e on the dielectric ceramic layer 1e through a via-hole conductor 5d provided so as to penetrate the dielectric ceramic layer 1f. The capacitance forming conductor 4c is connected to the capacitance forming conductor 4b via a via-hole conductor 6b provided so as to penetrate the dielectric ceramic layers 1f and 1e.

  On the dielectric ceramic layer 1g, a U-shaped coil forming conductor (corresponding to a coil forming bent conductor) 2g is formed. One end of the coil forming conductor 2g is connected to the coil forming conductor 2f on the dielectric ceramic layer 1f via a via-hole conductor 5e provided so as to penetrate the dielectric ceramic layer 1g.

  A U-shaped coil-forming conductor 2h is formed on the dielectric ceramic layer 1h. One end of the coil forming conductor 2h is connected to the coil forming conductor 2g on the dielectric ceramic layer 1g through a via-hole conductor 5f provided so as to penetrate the dielectric ceramic layer 1h. The other end of the coil forming conductor 2h is connected to the output terminal 2i.

  Finally, a protective dielectric ceramic layer 1i (not shown in FIG. 3) is laminated on the dielectric ceramic layer 1h.

  Since the structure is as described above, a three-and-a-half-turn coil is formed in a nine-layer laminated structure. As shown in FIG. 2, first capacitance forming conductors 4a, 4b, and 4c are sandwiched between the coil forming conductors 2b to 2h, and the first capacitance forming conductors 2b to 2h are first sandwiched between them. Capacity is formed. Further, the first capacitance forming conductor 4a is connected to the inductance forming conductor 7b and the second capacitance forming conductor 7a, and another capacitance is formed between the second capacitance forming conductor 7a and the GND conductor 3a. The The capacitance formed in this way is represented by hatched portions H1 and H2 in FIG. The hatched portion H1 represents a first capacitance formed between the capacitance forming conductors 4a, 4b, 4c and the coil forming conductors 2b to 2h, and the hatched portion H2 is connected to the second capacitance forming conductor 7a and GND. A second capacitance formed between the conductor 3a is shown.

  In FIG. 3, an example in which the first capacitance forming conductor 4a, the inductance forming conductor 7b, and the second capacitance forming conductor 7a are formed in the same insulating layer 1b has been described. However, the respective conductors 4a, 7b, and 7a are described. May be formed in different insulating layers.

  FIG. 4 is an equivalent circuit diagram of the filter element having the above configuration. Between the input terminal 2a of the signal line and the output terminal 2i, there exists a circular coil formed by the coil forming conductors 2b to 2h, and this circular coil and the first capacitance forming conductors 4a, 4b, 4c, A capacitance is formed between the first capacitance forming conductor 4a and the second capacitance forming conductor 7a, and an inductance forming conductor 7b is connected between the first capacitance forming conductor 7a and the second capacitance forming conductor 7a. A second capacitor is formed between the capacitor 3a and a low-pass filter element. A noise removal function or the like can be realized by this filter element.

The raw materials for the dielectric ceramic layers 1a to 1i are dielectric ceramic materials such as alumina (Al ₂ O ₃ ), barium titanate (BaTiO ₃ ), titanium dioxide (TiO ₂ ), or crystallization with these dielectric ceramic materials. It consists of a mixture such as glass.

  The coil forming conductors 2b to 2h, the GND conductor 3a, the capacitance forming conductors 4a to 4c, and the connection via-hole conductors 5a to 5f, 6a, and 6b are made of a conductive material mainly composed of Ag or the like.

  The input / output terminals 2a and 2i and the terminal 3 of the GND line are composed of a base conductor mainly composed of Ag and a layer such as Ni plating or solder plating attached to the surface thereof.

  Next, the manufacturing method of the above filter element is demonstrated.

  First, a green sheet is prepared by mixing a binder or the like with the above-mentioned mixture of dielectric ceramic material such as barium titanate as a main raw material, and via holes are formed at predetermined positions. In order to form the coil forming conductors 2b to 2h, the GND conductor 3a, the inductance forming conductor 7b, and the capacitance forming conductors 4a to 4c, 7a on the green sheet with via holes, a conductor paste mainly composed of Ag is used. Print in a predetermined pattern. Further, the conductor paste is embedded in the via hole. And each green sheet is laminated | stacked in a predetermined order, and after pressing and integrating, it cuts into each shape.

  By firing it at around 900 ° C., a rectangular parallelepiped ceramic laminate 1 as shown in FIG. 1 is produced. Furthermore, the input / output terminals 2a and 2i and the GND terminal 3 are formed on the surface of the ceramic laminate 1 by a printing method or a DIP method using a conductive paste mainly composed of Ag. The input / output terminals 2a and 2i and the GND terminal 3 are baked and subjected to Ni and solder plating, whereby a filter element chip is manufactured.

  In order to evaluate the filter characteristics of the filter element chip thus manufactured, S parameters (absolute values) were simulated.

  FIG. 5 is a diagram showing the frequency characteristics of the S parameter. The horizontal axis represents the frequency (GHz), and the vertical axis represents the S parameter transmission coefficient (S21) (unit dB). The solid curve A in the figure represents the frequency characteristic of the transmission coefficient (S21) in the structure of the present invention, and the broken curve B represents the frequency characteristic of the transmission coefficient (S21) of the filter element outside the range of the present invention. The broken line curve B is a case where the second capacitance forming conductor 7a and the inductance forming conductor 7b do not exist, and the second capacitance is formed between the first capacitance forming conductor and the grounding conductor.

  The filter element of the present invention (solid curve A) realizes an excellent low-pass filter characteristic at an attenuation peak on the low frequency side, and also has an attenuation peak in the vicinity of 3.2 GHz. Excellent attenuation in two bands Characteristics are obtained. On the other hand, in the filter (dashed curve B) that is outside the scope of the present invention, only the attenuation peak on the low frequency side is present, and the second attenuation pole is not generated.

  In the structure of the filter element of the present invention, since only one coil is configured as shown in FIG. 3, the conductor pattern is simple, and an excellent filter element suitable for miniaturization can be realized.

  FIG. 6 shows another structure of the filter element of the present invention. A grounding conductor 3a, a second capacitance forming conductor 7a, and an inductance forming conductor 7b are provided on the dielectric ceramic layer 1a. The conductor 3a and the second capacitance forming conductor 7a are connected by an inductance forming conductor 7b.

  In FIG. 6, the example in which the second capacitance forming conductor 7a, the inductance forming conductor 7b, and the GND conductor 3a are formed on the same insulating layer 1a has been described. However, the conductors 3a, 7b, and 7a are formed on different insulating layers. It may be formed.

  FIG. 7 is an equivalent circuit diagram of the filter element of FIG. Between the input terminal 2a of the signal line and the output terminal 2i, there exists a circular coil formed by the coil forming conductors 2b to 2h, and this circular coil and the first capacitance forming conductors 4a, 4b, 4c, In addition, a capacitance is formed between the first capacitance forming conductor 4a and the second capacitance forming conductor 7a, and the grounding conductor 3a and the second capacitance forming conductor 7a are connected by an inductance forming conductor 7b. A second capacitor is formed between the two, forming a low-pass filter element.

  An electronic module that realizes various functions can be manufactured by mounting the filter element described above on a mother board or the like.

  Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above-described embodiments. For example, the planar shape of the coil-forming conductors 2c, 2e, 2g is a U-shape, but it may be formed in a U-shape with a rounded corner. More broadly, the coil-forming bent conductor may be a curved or broken line continuous conductor having both ends. Other various modifications can be made within the scope of the present invention.

It is an external appearance perspective view of the filter element of this invention. It is sectional drawing of the filter element of this invention. It is a structure exploded perspective view when a dielectric ceramic layer is laminated. It is an equivalent circuit diagram of the filter element of the present invention. It is the frequency characteristic figure of S parameter calculated by simulation about the filter element of the present invention, and the filter element outside the range of the present invention. It is a structure exploded perspective view which shows the other form of the filter element of this invention. FIG. 7 is an equivalent circuit diagram of the filter element of FIG. 6. It is an equivalent circuit diagram of the conventional filter element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic laminated body 2a Input terminal 2i Output terminal 3 GND terminal 3 GND conductor (conductor for grounding)
1a-1i Dielectric ceramic layer (insulating layer)
2b to 2h Coil forming conductors 4a to 4c First capacitance forming conductor 7a Second capacitance forming conductor 7b Inductance forming conductors 5a to 5f Via hole conductors 6a and 6b Via hole conductors H1 First capacitance H2 Second capacitance

Claims (5)

A plurality of insulating layers formed with coil-forming conductors for constituting a coil that continuously circulates in a laminated state, and an insulating layer formed with a grounding conductor;
A first capacitor forming conductor that is not connected to either the coil forming conductor or the grounding conductor is formed in a part or all of the insulating layer, and the second capacitor forming conductor is interposed through the grounding conductor and the insulating layer. A conductor is formed, and the first capacitor forming conductor and the second capacitor forming conductor are connected by an inductance forming conductor;
A first capacitor is configured between the coil forming conductor and the first capacitive conductor.
A filter element comprising a second capacitor between the second capacitor forming conductor and the grounding conductor.   The filter element according to claim 1, wherein the inductance forming conductor, the second capacitance forming conductor, and the first capacitance forming conductor are formed in the same insulating layer. A plurality of insulating layers formed with coil-forming conductors for constituting a coil that continuously circulates in a laminated state, and an insulating layer formed with a grounding conductor;
A first capacitor forming conductor that is not connected to either the coil-forming conductor or the grounding conductor is formed on a part or all of the insulating layer, and the second capacitor-forming conductor and the insulating layer are interposed between the second capacitor-forming conductor and the insulating layer. A capacitance forming conductor is formed, and the grounding conductor and the second capacitance forming conductor are connected by an inductance forming conductor;
A first capacitor is configured between the coil forming conductor and the first capacitive conductor.
A filter element comprising a second capacitor between the second capacitor forming conductor and the first capacitor forming conductor.   The filter element according to claim 3, wherein the grounding conductor, the inductance forming conductor, and the second capacitance forming conductor are formed in the same insulating layer.   An electronic module comprising the filter element according to any one of claims 1 to 4.

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