JP2002026677A - Layered lc high pass filter and frequency branching circuit for mobile communication unit and front end module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a layered LC high pass filter that adopts a configuration of reducing stray capacitance caused between electrodes configured in a layered body so as to prevent the characteristic from being deteriorated, to provide a frequency branching circuit for a mobile communication unit employing the filter and to provide a front end module. SOLUTION: Common electrodes 5a-5c consisting of a plurality of layers are formed at an upper part in the layered body 1. A 1st capacitor electrode 6 and a 2nd ground terminal electrode 6 are formed on different layers so as to oppose to the common electrodes 5a-5c. A ground electrode 11 is formed at a lowermost part of the layered body 1. The ground electrode 11 and a capacitor electrode 10 formed thereon configure a 3rd capacitor C3. Inductor electrodes 9a, 9b are formed between the 3rd capacitor electrode 10 and the common electrode 5c. The inductor electrodes 9a, 9b and the 3rd capacitor electrode 10 may be formed up side down.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer LC high-pass filter used in a high-frequency region, a frequency demultiplexing circuit for mobile communication equipment, and a front-end module for mobile communication equipment. It relates to the electrode structure to be removed.

[0002]

2. Description of the Related Art A high-pass filter used in a high-frequency circuit for a mobile communication device such as a mobile phone is disclosed in Japanese Patent Application Laid-Open No. 11-261361.
This constitutes a T-type filter as shown in FIG. 6 (B), and is constituted as a laminate as shown in FIG. 6 (A). This filter comprises a first capacitor C1 and a second capacitor C1.
, And an inductor L and a third capacitor C3 inserted in series between the capacitors and the ground.

In FIG. 6A, 51 and 52 are opposed to a common electrode 53 so that the first capacitor C is provided.
1, and capacitor electrodes constituting the second capacitor C2. 54 is an inductor electrode constituting the inductor L. Reference numerals 55 and 56 denote ground electrodes formed at the uppermost and lowermost portions of the laminate 50. Reference numeral 57 denotes a capacitor electrode constituting the third capacitor C3. FIG.
Each electrode of (A) is shown corresponding to FIG. 6 (B). One end of the inductor electrode 54 is connected to the common electrode 53, and the other end is connected to the capacitor electrode 57.

[0004]

In the conventional filter described above, the inductor electrode 54 and the ground electrode 55
And a stray capacitance Cf2 is also generated between the capacitor electrode 52 and the capacitor electrode 57, thereby deteriorating the characteristics.

Accordingly, the present invention provides a multilayer LC high-pass filter having a configuration capable of reducing stray capacitance generated between electrodes formed in a multilayer body and preventing deterioration of characteristics, and a frequency component for mobile communication equipment using the same. It is an object to provide a wave circuit and a front-end module.

[0006]

The laminated LC high-pass filter according to the first aspect includes first and second capacitors connected in series between input and output terminals, and the first and second capacitors. An inductor and a third capacitor inserted between the ground and the ground and connected in series with each other.
Multilayer LC built in T-type filter built in multilayer
A high-pass filter, wherein the first capacitor and the second capacitor are formed in an upper part of the stacked body;
And the second capacitor are composed of a plurality of layers of common electrodes connected to each other and a first capacitor electrode and a second capacitor electrode formed so as to face opposite surfaces of these common electrodes. And one common electrode is in a lowermost layer of a portion forming the first capacitor and the second capacitor, a ground electrode is formed in a lowermost portion of the laminate, and the ground electrode and a capacitor electrode formed thereon are formed. Constitutes the third capacitor, an inductor electrode is connected between the third capacitor electrode and the common electrode, one end of which is connected to the common electrode, and the other end is the third capacitor electrode. Characterized by being formed by connecting to.

According to this structure, since the common electrode is interposed between the first and second capacitor electrodes and the third capacitor electrode, the first and second capacitor electrodes are provided. And the stray capacitance between the first capacitor electrode and the third capacitor electrode are reduced. Further, since the third capacitor electrode is interposed between the inductor electrode and the ground electrode, the stray capacitance between the inductor electrode and the ground electrode is reduced. Therefore, deterioration of characteristics due to stray capacitance is reduced.

According to a second aspect of the present invention, there is provided a multilayer LC high-pass filter.
First and second capacitors connected in series between input and output terminals, and an inductor and a third capacitor inserted between the first and second capacitors and the ground and connected in series with each other Is a laminated LC high-pass filter having a T-type filter built in a laminate, wherein the first capacitor and the second capacitor are formed in the upper part of the laminate, The capacitor and the second capacitor include a plurality of layers of common electrodes connected to each other, and a first capacitor electrode and a second capacitor electrode formed so as to face opposite surfaces of the common electrodes. And one common electrode is in a lowermost layer of a portion forming the first capacitor and the second capacitor, a ground electrode is formed at a lowermost portion of the stacked body, and is opposed to the lowermost layer under the common electrode. The third A capacitor electrode forming a capacitor is formed, an inductor electrode is connected between the third capacitor electrode and the ground electrode, one end of the inductor electrode is connected to the third capacitor electrode, and the other end is connected to the ground electrode. It is characterized by being formed by connection.

According to this structure, since the common electrode is interposed between the first and second capacitor electrodes and the third capacitor electrode, the first and second capacitor electrodes are provided. And the stray capacitance between the first capacitor electrode and the third capacitor electrode are reduced. Further, since one end of the inductor electrode is connected to the ground electrode, the stray capacitance between the inductor electrode and the ground electrode is reduced.
For this reason, deterioration of characteristics is reduced.

According to a third aspect of the present invention, there is provided a frequency demultiplexing circuit for a mobile communication device, wherein the laminated LC high-pass filter according to the first or second aspect is integrally formed as a high frequency side notch circuit together with other notch circuits in the laminate. I do.

According to a fourth aspect of the present invention, there is provided a front end module for a mobile communication device, wherein the frequency demultiplexing circuit according to the third aspect is integrated in a laminate.

According to a fifth aspect of the invention, there is provided a front end module for a mobile communication device, wherein the front module for a mobile communication device according to the fourth aspect switches transmission and reception of a plurality of different communication systems.

In the frequency demultiplexing circuit or the front-end module for mobile communication equipment according to the third to fifth aspects, the use of the laminated LC high-pass filter according to the first or second aspect reduces stray capacitance and improves characteristics. Is obtained in which the deterioration of the material is prevented. When the high-pass filter is integrated with other elements as a laminated component or when the laminated component is integrated with a mounted component as a substrate,
Since the inductor electrode is sandwiched between the capacitor electrode and the ground electrode, there is an advantage that it is hardly affected by other integrated elements.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A shows a laminate L according to the present invention.
FIG. 2 is a perspective view illustrating an embodiment of a C high-pass filter, showing an example in which a multilayer LC high-pass filter is configured as a single unit. 1 is a laminate of a dielectric and a conductor electrode, 2, 3
Are input / output terminal electrodes provided at both ends thereof, and 4 is a ground terminal electrode.

FIG. 1B is a sectional view of the laminated LC high-pass filter of the present embodiment, FIG. 1C is an equivalent circuit diagram thereof,
FIG. 2 is a diagram of a laminated structure. The basic configuration of the equivalent circuit shown in FIG. 1C is the same as the example of FIG. 6B, and the first capacitor C1, the second capacitor C2, and the third capacitor C3
And the inductor L constitute a T-type filter.

In the layer structure diagram of FIG. 2, reference numerals 1a to 1j denote dielectric green sheets, and reference numerals 5a, 5b and 5c denote common electrodes formed on the dielectric green sheets 1b, 1d and 1f by printing or the like. 6 denotes upper and lower common electrodes 5a, 5
and a first capacitor electrode formed on the dielectric green sheet 1c so as to constitute the first capacitor C1. Reference numeral 6a denotes a lead portion connected to the input / output terminal electrode 2.

Numeral 7 denotes second capacitor electrodes formed on the dielectric green sheet 1e so as to constitute the second capacitor C2 and sandwiched between the upper and lower common electrodes 5b and 5c. is there. Reference numeral 7a denotes a lead portion connected to the input / output terminal electrode 3. 8a to 8d are through holes for connecting the common electrodes 5a to 5c to each other.

Reference numerals 9a and 9b denote inductor electrodes formed on the dielectric green sheets 1g and 1h, respectively, so as to constitute the inductor L. Reference numeral 10 denotes a third capacitor electrode formed by facing the third capacitor C3 with the lowermost ground electrode 11, and these electrodes 10 and 11 are dielectric green sheets 1i and
1j. 8e is a through hole connecting the inductor electrode 9a and the lowermost common electrode 5c, 8f is a through hole connecting the inductor electrodes 9a and 9b,
8g is the inductor electrode 9b and the third capacitor electrode 10
This is a through hole that connects

In this filter, the green sheets 1b to 1j on which the respective electrodes are formed and the uppermost green sheet 1a are overlapped and pressed, cut into individual chips, fired,
It is manufactured by providing the terminal electrodes 2 to 4 by baking.

With this configuration, as shown in FIG. 1B, the first capacitor electrode 6 and the second capacitor electrode 7 are sandwiched between the common electrodes 5a and 5b, 5b and 5c. , The stray capacitance between the first capacitor electrode 6 and the second capacitor electrode 7 and the third capacitor electrode 10 is reduced. Further, since the third capacitor electrode 10 is interposed between the inductor electrodes 9a and 9b and the ground electrode 11, the stray capacitance between the inductor electrodes 9a and 9b and the ground electrode 11 is reduced. Therefore, deterioration of characteristics due to stray capacitance is reduced.

Such a laminated LC high-pass filter is
The present invention can be applied to a front end module of a mobile communication device such as a mobile phone as shown in FIG. In FIG. 3, reference numerals 14 and 15 denote transmission terminals of different communication systems, respectively, input terminals to the front-end module, and 16 and 17.
Is a reception signal output terminal, 18 and 19 are low-pass filters for removing high-frequency noise from transmission signals of each communication system,
Reference numerals 20 and 21 denote transmission / reception switching circuits, reference numeral 22 denotes a frequency demultiplexing circuit (diplexer) including a low-pass filter 23 and a high-pass filter 24, which are notch circuits, and reference numeral 25 denotes an antenna.

The multilayer LC high-pass filter of the present invention can be used as a high-pass filter 24 of a frequency demultiplexing circuit 22 used for a plurality of communication systems. Further, it can be configured as an integrated chip together with the low-pass filter 23 of the frequency demultiplexing circuit 22. Further, it can be configured as an integrated component including a laminated chip in which a part of the elements of the front end module 13 is integrated, and a component mounted with the chip as a substrate.
When integrated as described above, the inductor electrodes 9a,
Since 9b is sandwiched between the capacitor electrodes 5c and 10 and the ground electrode 11, there is an advantage that it is hardly affected by other integrated elements. The front-end module 13 may include a band-pass filter of a receiving circuit. When a high-pass filter is formed together with a plurality of elements in one laminated body, a structure is adopted in which the high-pass filter and other elements are connected by an internal conductor without passing through the input / output terminal electrodes 2 and 3. In some cases.

FIG. 4A is a sectional view showing another embodiment of the present invention, FIG. 4B is an equivalent circuit diagram thereof, and FIG. 5 is a layer structure diagram thereof. In the present embodiment, the third capacitor electrode 10 is connected to the lowermost electrode 5c of the common electrodes 5a to 5c.
The inductor electrodes 9a and 9b are provided between the third capacitor electrode 10 and the ground electrode 11 with both ends connected by through holes 8e and 8g.
The inductor electrodes 9a and 9b are connected by a through hole 8f. The configurations of the common electrodes 5a to 5c, the first capacitor electrode 6, and the second capacitor electrode 7 are the same as described above.

Also in this embodiment, the first capacitor electrode 6 and the second capacitor electrode 7 are sandwiched between the common electrodes 5a and 5b and 5b and 5c, respectively. The stray capacitance between the capacitor electrode 6, the second capacitor electrode 7, and the third capacitor electrode 10 is reduced. Also, since one end of the inductor electrode 9b is connected to the ground electrode 11, the inductor electrodes 9a, 9
The stray capacitance between b and the ground electrode 11 is reduced.
For this reason, deterioration of characteristics is reduced.

Also, in the embodiments of FIGS. 4 and 5, the high-pass filter is integrated with other elements as a laminated component or laminated as the frequency demultiplexing circuit 22 and the front end module 13 shown in FIG. When the component is integrated with the mounted component as a substrate, the inductor electrodes 9a and 9b are
, There is an advantage that it is hard to receive from other integrated elements.

The laminated LC high-pass filter of the present invention can be manufactured not as a ceramic sintered body but as a resin-made one using a prepreg.

[Brief description of the drawings]

1A is a perspective view showing an embodiment of a laminated LC high-pass filter according to the present invention, FIG. 1B is a cross-sectional view thereof,
(C) is an equivalent circuit diagram thereof.

FIG. 2 is a diagram showing a laminated structure according to the embodiment of FIG. 1;

FIG. 3 is a block diagram showing a configuration example of a front end module for a mobile communication device to which the present invention is applied.

FIG. 4A is a sectional view showing another embodiment of the laminated LC high-pass filter according to the present invention, and FIG. 4B is an equivalent circuit diagram thereof.

FIG. 5 is a diagram showing a laminated structure of the embodiment of FIG. 4;

6A is a cross-sectional view of a conventional multilayer LC high-pass filter, and FIG. 6B is an equivalent circuit diagram thereof.

[Explanation of symbols]

1: laminate, 1a to 1j: dielectric green sheet, 2,
3: input / output terminal electrode, 4: ground terminal electrode, 5a to 5
c: common electrode, 6; first capacitor electrode, 7: second capacitor electrode, 8a to 8g: through hole, 9a, 9
b: inductor electrode, 10: third capacitor electrode, 1
1: ground electrode, 13: front-end module,
14, 15: transmission signal input terminal, 16, 17: reception signal output terminal, 18, 19: low-pass filter, 20, 21: transmission / reception switching circuit, 22: frequency demultiplexing circuit, 23: low-pass filter, 24: high-pass filter, 25: antenna, C1: first capacitor, C2: second capacitor, C3: third capacitor, L: inductor

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H01G 4/30 301 H03H 7/46 A 4/40 H01F 15/00 D H03H 7/46 H01G 4/40 321A F term ( Reference) 5E001 AB03 AC08 AD00 AF06 5E070 AA01 AA05 AB01 BA12 CB03 CB13 CB17 EA01 5E082 AA01 AB03 DD08 EE04 EE16 EE23 EE35 FF05 FG06 FG26 GG10 5J024 AA01 BA03 CA02 DA04 DA29 DA35 EA02

Claims (5)

[Claims] A first and a second capacitor connected in series between input and output terminals, and an inductor inserted between the first and second capacitors and a ground and connected in series with each other. And a third capacitor built in a laminate to form a T-type filter, wherein the first capacitor and the second capacitor are formed in the upper part of the laminate. The first capacitor and the second capacitor include a plurality of layers of common electrodes connected to each other, and a first capacitor electrode and a second capacitor electrode formed to face opposite surfaces of the common electrodes. A common electrode is provided at a lowermost layer of a portion constituting the first capacitor and the second capacitor, and a ground electrode is formed at a lowermost portion of the laminated body; form The third capacitor is constituted by the capacitor electrode to be connected, an inductor electrode is connected between the third capacitor electrode and the common electrode, one end of which is connected to the common electrode, and the other end is the third capacitor. A laminated LC high-pass filter formed by connecting to a capacitor electrode of (1). 2. A first and a second capacitor connected in series between an input / output terminal, and an inductor inserted between the first and second capacitors and a ground and connected in series with each other. And a third capacitor built in a laminate to form a T-type filter, wherein the first capacitor and the second capacitor are formed in the upper part of the laminate. The first capacitor and the second capacitor include a plurality of layers of common electrodes connected to each other, and a first capacitor electrode and a second capacitor electrode formed to face opposite surfaces of the common electrodes. A common electrode is provided at a lowermost layer of a portion constituting the first capacitor and the second capacitor, a ground electrode is formed at a lowermost portion of the laminated body, and a common electrode of the lowermost layer is formed. Pair below Forming a capacitor electrode constituting the third capacitor, connecting an inductor electrode between the third capacitor electrode and the ground electrode, one end of which is connected to the third capacitor electrode, and A laminated LC high-pass filter having an end connected to the ground electrode. 3. A frequency demultiplexing circuit for mobile communication equipment, wherein the laminated LC high-pass filter according to claim 1 or 2 is integrally formed as a high frequency side notch circuit in a laminate together with other notch circuits. 4. A front end module for a mobile communication device, wherein the frequency demultiplexing circuit according to claim 3 is integrated in a laminate. 5. A front end module for a mobile communication device according to claim 4, wherein the front end module for a mobile communication device switches transmission and reception of a plurality of different communication systems.