JP2003124771A - Demultiplexer for dual-band mobile phone terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small and high performance demultiplexer with a new structure. SOLUTION: The demultiplexer used for a dual-band mobile phone terminal corresponding to two frequency bands of f1 and f2 has a first notch circuit comprising a capacitor component and an inductance component and passing the frequency band f1 and a second notch circuit comprising a capacitor component and an inductance component and passing the frequency band f2. An end to which the first notch circuit and the second notch circuit are connected is connected to an antenna side of the dual-band mobile phone, the other end of the first notch circuit is connected to a communication circuit handling the frequency band f1, the other end of the second notch circuit is connected to a communication circuit side handling the frequency band f2, a signal is branched to each of the communication circuit sides of the frequency bands f1 and f2, and thereby, it is possible to select one frequency band of the two frequency bands and to talk over the dual-band mobile phone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a demultiplexer used in a microwave band, and more particularly to a demultiplexer used for band demultiplexing of a dual band mobile phone.

[0002]

2. Description of the Related Art A circuit diagram of a conventional duplexer is shown in FIG. This conventional example has a structure in which an LPF (low-pass filter) and an HPF (high-pass filter) are combined. Further, Japanese Laid-Open Patent Publication No. 3-216002 describes a duplexer having the block diagrams shown in FIGS. 8 and 9. The duplexer of FIG. 8 has a structure in which an LPF is further connected to the HPF of the circuit of FIG. 7, and the duplexer of FIG. 9 is the LPF and HP of the duplexer of FIG.
This is a structure in which REJ (rejection filter) is added to F.

A dielectric coaxial resonator is generally used for these filters. This has a structure in which electrodes are formed on the inner peripheral surface and the outer peripheral surface of a cylindrical body made of a dielectric porcelain, which is not suitable for miniaturization in terms of shape.

[0004]

The spread of mobile phones in recent years has been remarkable, and the functions of mobile terminals have been improved. As one of them, a dual-band mobile phone has been proposed, which enables one mobile terminal to make a call in two frequency bands. In order to construct this dual band mobile phone, a function of selecting the two frequencies is required. Moreover, it is necessary to construct a small duplexer for use in a mobile terminal.

For example, in the configuration of the conventional duplexer shown in FIG. 7, f1 = 824 to 894 MHz, f2 = 1850 to 1
Figure 1 shows the insertion loss as a result of constructing a 990MHz duplexer.
It shows in 0. In this conventional example, the attenuation is 5 to 1
0 dB, the sneak of the other frequency component into each frequency band is large, and the respective frequencies f1 and f2 are
In, the insertion loss characteristic was not good.

Further, if the circuit configuration shown in FIG. 8 or 9 is used, the insertion loss characteristic can be improved at the respective frequencies f1 and f2, but since the circuit becomes complicated, the duplexer becomes large. . For example, considering that it can be used for mobile phones, large-sized duplexers cannot be used,
A compact and high-performance duplexer is desired.

It is an object of the present invention to construct a duplexer having a novel structure, and to provide a compact and high-performance duplexer.

[0008]

A first aspect of the present invention is a duplexer used in a dual band portable telephone terminal device corresponding to two frequency bands f1 and f2, which is a frequency band f1 composed of a capacitor component and an inductance component. Has a first notch circuit that passes through the first notch circuit and a second notch circuit that passes through the frequency band f2 composed of a capacitor component and an inductance component, and has a dual end portion connecting the first notch circuit and the second notch circuit. A band mobile phone terminal is connected to the antenna side, the other end of the first notch circuit is connected to the communication circuit side that handles the frequency band f1, and the other end of the second notch circuit is a communication that handles the frequency band f2. Connected to the circuit side, frequency bands f1, f2
By demultiplexing the signal to each of the communication circuit side of
A duplexer for a dual-band mobile phone terminal, which enables a call by selecting one of two frequency bands in the dual-band mobile phone terminal.

In the present invention, the first and second notch circuits composed of the inductance component and the capacitor component are made of a ceramic dielectric material which can be fired at 950 ° C. or lower and has a dielectric constant of 5 to 15 as an insulating layer. It is preferable that the pattern electrodes are formed inside a laminated body that is integrally laminated. It is also preferable that the pattern electrodes forming the inductance component and the capacitor component are formed in different insulating layers inside the laminated body. Further, it is preferable that the pattern electrode forming the inductance component is formed of a line electrode divided into two directions on one plane. In the present invention, the attenuation in the frequency band f2 of the first notch circuit is 15 dB or more, and the attenuation in the frequency band f1 of the second notch circuit is 15 dB or more.

A second aspect of the present invention is a dual band portable telephone terminal using the duplexer for the dual band portable telephone terminal of the first aspect.

In the present invention, the inductance component and the capacitor component are formed in the laminated body. The inductance component is preferably composed of meander lines, but may be formed in a wound shape. Further, the capacitor component can be formed by facing the electrodes, and the capacitance can be adjusted by the area and the interval.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an equivalent circuit diagram of an embodiment according to the present invention. The duplexer of this embodiment has a first notch circuit 1 in which an inductance component L1 and a capacitor component C1 are connected in parallel, and a second notch circuit 2 in which an inductance component L2 and a capacitor component C2 are similarly connected in parallel. It consists of and. The two notch circuits 1,
One end of 2 is connected to form a branching circuit. Accordingly, when a specific frequency f1 is passed through T1 to T2, the insertion loss of the second notch circuit 2 is configured to be maximum at the frequency f1, and the signal is not output to T3. When passing a specific frequency f2 at T1 to T3, the insertion loss of the first notch circuit 1 is
It is configured such that it becomes the maximum, and is configured so as not to output a signal to T2, and is demultiplexed.

Another equivalent circuit diagram of the embodiment according to the present invention is shown in FIG. The duplexer of this embodiment has a first component in which an inductance component L1 and a capacitor component C1 are connected in series.
And a second notch circuit 2 in which an inductance component L2 and a capacitor component C2 are connected in series. The two notch circuits 1, 2
The two ends of are connected to form a branching circuit. Accordingly, when a specific frequency f1 is passed through T1 to T2, the insertion loss of the second notch circuit 2 is configured to be maximum at the frequency f1, and the signal is not output to T3. When passing a specific frequency f2 at T1 to T3, the insertion loss of the first notch circuit 1 is
It is configured such that it becomes the maximum, and is configured so as not to output a signal to T2, and is demultiplexed.

FIG. 3 shows a laminated structure of one embodiment according to the present invention, and FIG. 4 is a perspective view thereof. This example is an example of a chip-shaped laminated duplexer configured by using a sheet laminating method. First, a ceramic green sheet is prepared.
In this example, a ceramic dielectric material that can be fired at a low temperature of 950 ° C. or lower was used. The dielectric constant is 8. A predetermined number of these ceramic green sheets are laminated and configured. First, an insulating layer (ceramic green sheet) 11 on which a pattern electrode is not formed is arranged as a lower layer, and an insulating layer 12 on which a pattern electrode for forming a capacitor component is formed is laminated thereon. Two pattern electrodes 21 and 22 for forming a capacitor component are formed on the insulating layer 12, and the pattern electrodes 21 and 22 have lead electrodes 21a and 22a led to the end faces. A pattern electrode 23 for forming a capacitor component is formed on the insulating layer 13 laminated thereon, and from the pattern electrode 23, a lead electrode 23a led to the end face.
have. On the insulating layer 14 laminated thereon,
A pattern electrode that constitutes an inductance component is formed. In this pattern electrode, the line electrode extending from the extraction electrode 31a extracted on one end face is divided into two directions,
The line electrodes 31b and 31c for the inductance component are formed. A through-hole round electrode 42 is formed at the end of the line electrode 31b, and another line electrode 31c is formed at the other end to form a lead electrode 31d. One line electrode 31e is formed on the insulating layer 15 laminated thereon. The line electrode 31e has a lead electrode 31f led to the end face,
A through hole electrode 41 is formed at the other end. Then, the insulating layer 16 on which no pattern electrode is formed is laminated thereon. This laminated body was integrally fired at about 900 ° C., and the terminal electrodes 51, 61, 62 were formed on the side surfaces to form a laminated duplexer. The pattern electrodes and line electrodes were formed by screen-printing Ag paste.

In this embodiment, the line electrodes 31e and 31e
b is connected by the through-hole electrode 41 and the through-hole round electrode 42, and constitutes one inductance component. In addition, one extraction electrode 31a of the line electrode and the extraction electrode 23 of the pattern electrode 23 for forming the capacitor component.
The a is drawn out at the same position on the side surface and is electrically connected to each other by the terminal electrode 51 formed on the side surface. Further, the extraction electrode 31f of one line electrode 31e and the extraction electrode 21a of the pattern electrode 21 for forming the capacitor component are also extracted to the same location on the side surface thereof, and are electrically connected to each other by the terminal electrode 62 formed on the side surface. Further, the extraction electrode 31d of one line electrode 31c and the extraction electrode 22a of the pattern electrode 22 for forming the capacitor component are also extracted at the same location on the side surface thereof and are electrically connected to each other by the terminal electrode 61 formed on the side surface.

This embodiment constitutes the duplexer shown in the circuit diagram of FIG. That is, C1 is the pattern electrode 2
3 and 22, L1 is a line electrode 31c, C2 is a pattern electrode 23 and 21, and L2 is a line electrode 31b and 31e.

The line electrode forming this inductance component can be appropriately selected such as meander line or spiral line, and may be formed on one layer, or formed on two or more layers and connected by through holes or the like. May be. The capacitor component forming electrode may be formed by facing two electrodes, but may be formed by facing three or more electrodes. The insulating layer has a dielectric constant of 8
The material is not limited to the above. The preferred dielectric constant is
5 to 15.

FIG. 5 shows a laminated structure diagram of another embodiment according to the present invention. This example is an example of a chip-shaped laminated duplexer configured by using a sheet laminating method. First,
Prepare a ceramic green sheet. In this embodiment,
A ceramic dielectric material that can be fired at a low temperature of 950 ° C. or lower was used. The dielectric constant is 8. A predetermined number of these ceramic green sheets are laminated and configured. First, an insulating layer (ceramic green sheet) 71 on which no pattern electrode is formed is arranged as a lower layer, and an insulating layer 72 on which a pattern electrode for forming a capacitor component is formed is laminated thereon. Two pattern electrodes 81 and 82 for forming capacitor components are formed on the insulating layer 72, and the respective pattern electrodes 81 and 82 have lead electrodes 81a and 82a led to the end faces. A pattern electrode 83 for forming a capacitor component is formed on the insulating layer 73 laminated thereon, and from the pattern electrode 83,
It has a lead electrode 83a led to the end face. On the insulating layer 74 laminated thereon, a pattern electrode forming an inductance component is formed. In this pattern electrode, a line electrode extending from a lead electrode 84a led to one end face is divided into two directions to form line electrodes 84b and 84c for inductance components. The line electrodes 84b and 84c are led out to their end faces to form lead electrodes 84d and 84e, respectively. Then, an insulating layer 75 having no pattern electrode formed thereon is laminated thereon. This laminated body was integrally fired at about 900 ° C., and terminal electrodes were formed on the side surfaces to form a laminated duplexer. The pattern electrodes and line electrodes were formed by screen-printing Ag paste.

Further, in the duplexer of the present invention, the two notch circuits are the main circuits, but a high pass filter circuit or a low pass filter circuit may be connected to each notch circuit to improve the branching characteristics. Conceivable.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The laminated duplexer shown in FIGS.
In the equivalent circuit shown in, C1 is 1.6 pF and L1 is 4 pF.
A demultiplexer was constructed with nH, C2 of 3.2 pF, and L2 of 10 nH. The insertion loss characteristic of this embodiment is shown in FIG. This duplexer sets f1 to 860 MHz and f2 to 19
It is set to 20 MHz. In this embodiment, the f1 frequency band is 824 to 894 MHz, and the f2 frequency band is 1850 to
Used for band demultiplexing for 1990 MHz dual band mobile phones. The external dimensions of this laminated duplexer are
The size was 4.5 mm × 3.2 mm, and the height was 1.7 mm, which was extremely small. As shown in FIG. 6, in the duplexer of the present invention, the attenuation is 15 dB or more, and the sneak of one frequency component into each frequency band is small,
It has excellent characteristics as a duplexer.

According to the present invention, since the duplexer is constructed by the laminated structure, a very small duplexer can be constructed. Moreover, since it has a simple circuit configuration in which two LC notch circuits are combined, a laminated structure can be easily configured.

[0022]

According to the present invention, it is possible to construct a small duplexer having excellent branching characteristics. As a result, in a small microwave product such as a mobile phone, it is possible to contribute to downsizing of the entire device without sacrificing the characteristics.
In particular, it is effective in a dual band mobile phone.

[Brief description of drawings]

FIG. 1 is an equivalent circuit diagram of an embodiment according to the present invention.

FIG. 2 is another equivalent circuit diagram of the embodiment according to the present invention.

FIG. 3 is a layered structure diagram of an embodiment according to the present invention.

FIG. 4 is a perspective view of an embodiment according to the present invention.

FIG. 5 is a laminated structure diagram of another embodiment according to the present invention.

FIG. 6 is an insertion loss characteristic of the example according to the present invention.

FIG. 7 is a circuit diagram of a conventional example.

FIG. 8 is a block diagram of a conventional example.

FIG. 9 is a block diagram of a conventional example.

FIG. 10 is an insertion loss characteristic of a conventional example.

[Explanation of symbols]

11, 12, 13, 14, 15, 16, 71, 72, 7
3, 74, 75 Insulating layers 21, 22, 23, 81, 82, 83 Capacitor component forming pattern electrodes 31b, 31c, 31e, 84b, 84c Line electrodes 21a, 22a, 23a, 31a, 31d, 31f, 8
1a, 82a, 83a, 84a, 84d, 84e Lead-out electrode 41 Through-hole electrode 42 Through-hole round electrode 51, 61, 62 Terminal electrode

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[Procedure amendment]

[Submission date] October 4, 2002 (2002.10.
4)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

The spread of mobile phones in recent years has been remarkable, and the functions of mobile terminals have been improved. As one of them, a dual-band mobile phone has been proposed, which enables one mobile terminal to make a call in two frequency bands. In order to construct this dual band mobile phone, a function of selecting the two frequencies is required. Moreover, in order to use it for a mobile terminal, it is necessary to make it compact.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

In view of such demands, the present inventors have decided to demultiplex
Inspired by the function of selecting the two frequencies
did. However, for example, in the configuration of the conventional duplexer shown in FIG. 7, f1 = 824 to 894 MHz, f2 = 185
It divides the transmission and reception signals of two frequency bands of 0-1990MHz.
The insertion loss of the result of constituting the duplexer to the waves shown in FIG. 10. In this conventional example, the attenuation is 5 to 10 dB.
In other words, the sneak of the other frequency component into each frequency band was large, and the insertion loss characteristics were not good at the respective frequencies f1 and f2.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

Further, if the circuit configuration shown in FIG. 8 or FIG. 9 is used, the insertion loss characteristic can be improved in each of the frequency bands 1 and f2, but since the circuit becomes complicated, the duplexer becomes large. Become. For example, considering that it can be used for mobile phones, large-sized duplexers cannot be used,
A compact and high-performance duplexer is desired.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

According to the present invention, a transmission / reception signal in the frequency band f1 and a frequency
Dual-band mobile that supports transmission / reception signals in wavenumber band f2
In the telephone terminal, the duplexer selects two frequencies
With a small, high-performance duplexer that does not have functions
It can be used for dual-band mobile phone terminals and
Dual-band transmission and reception of dual-band mobile phone handsets
It is an object to provide a signal selection method .

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

A first invention is a frequency band.
It corresponds to the transmission / reception signal of f1 and the transmission / reception signal of frequency band f2.
Is a duplexer used in dual band mobile phone handsets.
Is composed of a capacitor component and an inductance component.
Transmission / reception signals of several bands f1 are passed and transmission / reception of frequency band f2
First notch circuit for attenuating signal and capacitor component
And frequency component f2
Signal to pass the signal and attenuate the transmission / reception signal in the frequency band f1.
2 notch circuit, the first notch circuit is dual
Communication circuit for antenna and frequency band f1
And the second notch circuit with dual band
Between the antenna of the band telephone and the communication circuit that handles the frequency band f2
And connect the first notch circuit and the second notch circuit.
Connected end to dual band mobile phone antenna side
Then, by demultiplexing the signals on the respective communication circuits of the frequency bands f1 and f2, a dual band mobile phone that enables a call by selecting one of the transmission and reception signals of two frequency bands in the dual band mobile phone It is a duplexer for terminals.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

In the present invention, the first and second notch circuits composed of the inductance component and the capacitor component are made of a ceramic dielectric material which can be fired at 950 ° C. or lower and has a dielectric constant of 5 to 15 as an insulating layer. It is preferable that the pattern electrodes are formed inside a laminated body that is integrally laminated. It is also preferable that the pattern electrodes forming the inductance component and the capacitor component are formed in different insulating layers inside the laminated body. Further, it is preferable that the pattern electrode forming the inductance component is formed of a line electrode divided into two directions on one plane. Also, the first notch circuit and the second notch circuit
Pattern electrode that constitutes the inductance component of the switch circuit
Are connected on one plane in the laminate, and
It is also preferable to pull out to the side surface of the laminate. In the present invention, the attenuation in the frequency band f2 of the first notch circuit is 15 dB or more, and the attenuation in the frequency band f1 of the second notch circuit is 15 d.
B or higher.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

A second invention is a dual-band mobile phone terminal using the duplexer for the dual-band mobile phone terminal of the first invention. The third invention is transmission of the frequency band f1.
Dual corresponding to received signal and transmitted / received signal in frequency band f2
Of the two frequency bands in the Luband mobile phone
This is a method of selecting the transmission / reception signal,
The transmitted and received signals in the frequency band f1
The first noise which attenuates the transmission / reception signal in the frequency band f2
Dual-band mobile phone antenna and frequency
It is placed between the communication circuit handling band f1 and the capacitor component.
And frequency component f2
Signal to pass the signal and attenuate the transmission / reception signal in the frequency band f1.
2 notch circuit with dual band mobile phone antenna
It is arranged between the communication circuit handling the frequency band f2 and the first node.
Switch circuit and second notch circuit are connected to the end
Connected to the antenna side of the band mobile phone, the frequency band f1,
By demultiplexing the signal to each of the communication circuit side of f2
In a dual-band mobile phone, two frequency bands
Select either the send / receive signal to enable the
Transmission and reception of two frequency bands of an Arband mobile phone
This is the method of selecting the issue.

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Claims (6)

[Claims] 1. A demultiplexer used in a dual band mobile phone terminal corresponding to two frequency bands f1 and f2, the first notch circuit passing a frequency band f1 composed of a capacitor component and an inductance component, It has a second notch circuit that passes a frequency band f2 composed of a capacitor component and an inductance component, and connects the end portion connecting the first notch circuit and the second notch circuit to the antenna side of the dual band mobile phone, The other end of the first notch circuit is connected to the communication circuit side that handles the frequency band f1, and the other end of the second notch circuit is connected to the frequency band f2.
By connecting to the communication circuit side that handles the signal and demultiplexing the signals into the communication circuit sides of the frequency bands f1 and f2, it becomes possible to select either of the two frequency bands in the dual-band mobile phone and make a call. A duplexer for a dual-band mobile phone terminal characterized by: 2. The first and second notch circuits consisting of an inductance component and a capacitor component are laminated and integrated by using an insulating layer of a ceramic dielectric material that can be fired at 950 ° C. or less and has a dielectric constant of 5 to 15. The duplexer for a dual-band mobile phone terminal according to claim 1, wherein the duplexer is formed of a pattern electrode formed inside the laminated body. 3. The dual band mobile phone terminal according to claim 2, wherein pattern electrodes forming the inductance component and the capacitor component are formed in different insulating layers inside the laminate. For duplexer. 4. The dual-band mobile phone terminal demultiplexer according to claim 2, wherein the pattern electrode forming the inductance component is formed of a line electrode divided in two directions on one plane. vessel. 5. The attenuation in the frequency band f2 of the first notch circuit is 15 dB or more, and the attenuation in the frequency band f1 of the second notch circuit is 15 dB or more. The duplexer for a dual band mobile phone terminal according to any one of 1. 6. A dual-band mobile phone terminal using the duplexer for a dual-band mobile phone terminal according to claim 1.