JP2000349581A - Diplexer and mobile communication equipment using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diplexer with a structure where a pass band of a high- pass filter between 2nd and 3rd ports is widened and the insertion loss is decreased and to provide a mobile communication equipment employing it. SOLUTION: The diplexer 10 is provided with a multi-layered board 11 consisting of 1st-9th dielectric layers 111-119, and strip line electrodes ST11, ST12, capacitor electrodes Cp11-Cp16, and ground electrodes Gp11, Gp12 are formed on an upper face of the 2nd-9th dielectric layers 112-119 respectively. The 1st-9th dielectric layers 111-119 are stacked and integrally baked to form the multi-layered board 11. Moreover, external terminals T11-T14 are formed on side faces and front and rear faces of the multi-layered board 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diplexer and a mobile communication device using the same, and more particularly, to a diplexer for separating and combining high-frequency signals having different frequencies and a mobile communication device using the same.

[0002]

2. Description of the Related Art Conventionally, high frequency signals having different frequencies with one antenna, for example, GSM (Global System for Mo
bile communications) and DCS (Digital Cellular)
In order to cope with System, a diplexer capable of separating and synthesizing high-frequency signals having different frequencies is used.

FIG. 6 is an equivalent circuit diagram of a general diplexer. The diplexer has first to third ports P1 to P1.
P3, low-pass filter LP between first and second ports
F, and a high-pass filter HPF between the second and third ports. The low-pass filter LPF includes a first inductor L1 and first capacitors C11 and C12, and is provided between a first port P1 and a second port P2.
A parallel circuit composed of a first inductor L11 and a first capacitor C11 is connected, and a first capacitor C12 is connected between the first port P1 and the ground. The high-pass filter HPF includes a second inductor L2 and second capacitors C21 to C23, and a second port P2
Between the second capacitor C2 and the third port P3.
1 and C22 are connected in series, and a second capacitor C21,
A series circuit including the second inductor L2 and the second capacitor C23 is connected between the connection point of C22 and the ground.

FIG. 7 is an exploded perspective view of a conventional diplexer. The diplexer 50 includes the first to seventh sheet layers 5.
A multi-layer substrate 51 including 11 to 517 is provided. Capacitor electrodes Cp51, Cp52, capacitor electrodes Cp53, Cp54, and capacitor electrodes Cp55, Cp5 are provided on the upper surfaces of the second, third, and sixth sheet layers 512, 513, 516.
6 are respectively formed. In addition, the fourth sheet layer 514
Are formed with strip line electrodes ST51 and ST52. Further, fifth and seventh sheet layers 515,
A ground electrode Gp51 and a ground electrode Gp52 are formed on the upper surface of 517, respectively. In addition, the second to fifth sheet layers 512 to 515 have respective sheet layers 512 to 515.
Via hole electrode Vh5 is formed to penetrate through.

The first to seventh sheet layers 511 to 5
17 are stacked and integrally sintered,
The multilayer substrate 51 is obtained. Then, the strip line electrode S
T51 and capacitor electrodes Cp51, Cp53, Cp5
5, and the strip line electrode ST52 and the capacitor electrodes Cp54 and Cp56 are connected to each other via the via hole electrode Vh5 inside the multilayer substrate 51. The capacitor electrode Cp51 is provided on the side and front and back surfaces of the multilayer substrate 51.
And first and second ports P1, P2
(FIG. 6) are electrically connected to the external terminals T51 and T52 and the capacitor electrode Cp52, and the third port P3
(FIG. 6), an external terminal T53 and a ground electrode Gp5.
1, an external terminal T54 which is electrically connected to Gp52 and serves as a ground terminal is formed.

[0006] In the diplexer 50 having the above-described structure, the strip line electrodes ST51 and ST52 form the first.
And the second inductors L1 and L2 (FIG. 6). Further, the first capacitor C11 (FIG. 6) and the capacitor electrode Cp5 are connected by the capacitor electrodes Cp51 and Cp53.
5 and the ground electrodes Gp51 and Gp52 form a first capacitor C12 (FIG. 6). Further, the second capacitor C2 is connected to the capacitor electrodes Cp51 and Cp54.
1 (FIG. 6), the capacitor electrodes Cp52 and Cp54
Capacitor C22 (FIG. 6), capacitor electrode Cp56
And the ground electrodes Gp51 and Gp52 form a second capacitor C23 (FIG. 6).

[0007]

However, according to the above-described conventional diplexer, in the high-pass filter between the second and third ports, a series connection is made between the second and third ports. A stray capacitance occurs between the capacitor electrode forming the second capacitor and the ground electrode, and the equivalent circuit has a form in which a capacitor is added as shown by a broken line in FIG. In the high-pass filter between the second and third ports, the stripline electrode forming the second inductor is close to the ground electrode, and the impedance of the stripline electrode is reduced. As a result, there is a problem that the pass band of the high-pass filter between the second and third ports is narrowed and the insertion loss is increased.

The present invention has been made to solve such a problem, and has a structure for widening the pass band of a high-pass filter between the second and third ports and reducing insertion loss. It is an object to provide a diplexer having the same and a mobile communication device using the same.

[0009]

In order to solve the above-mentioned problems, a diplexer according to the present invention comprises a first to a third port and a low-pass filter forming a low-pass filter between the first and the second ports. A first inductor and a first capacitor, and a second inductor and a second capacitor forming a high-pass filter between the second and third ports, and the first and second inductors are A diplexer formed by a strip line electrode built in a multilayer substrate formed by laminating a plurality of sheet layers made of ceramics, wherein the first and second capacitors are formed by capacitor electrodes built in the multilayer substrate. Wherein the second capacitor connected in series between the second port and the third port is connected between the first port and the second port. That is disposed on the first capacitor, and wherein the stacking height direction of the multilayer substrate.

[0010] The first and second capacitors may include:
It is not arranged on the second inductor.

[0011] A mobile communication device according to the present invention is characterized by using the above diplexer.

According to the diplexer of the present invention, the second capacitor connected in series between the second port and the third port is connected between the first port and the second port. The capacitor electrode forming the first capacitor is inserted between the capacitor electrode forming the second capacitor and the ground electrode to be arranged on the first capacitor and stacked in the height direction of the multilayer substrate. That means
The stray capacitance generated between the capacitor electrode forming the second capacitor and the ground electrode can be suppressed.

According to the mobile communication apparatus of the present invention, the transmission characteristics and the reception characteristics are obtained because the diplexer which increases the pass band of the high-pass filter between the second and third ports and reduces the insertion loss is used. This makes it possible to obtain a mobile communication device that is excellent in quality.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first example of the diplexer of the present invention.
FIG. 3 is an exploded perspective view of the embodiment. The diplexer 10 includes a multilayer substrate 1 including first to ninth sheet layers 111 to 119.
1 is provided. Capacitor electrodes Cp11 to Cp14 are formed on the upper surfaces of the second to fifth sheet layers 112 to 115, respectively. Further, strip line electrodes ST11 and ST12 are formed on the upper surface of the sixth sheet layer 116.

Further, the seventh and ninth sheet layers 117,
Ground electrodes Gp11 and Gp12 are formed on the upper surface of 119, respectively. Further, capacitor electrodes Cp15 and Cp16 are formed on the upper surface of the eighth sheet layer 118.
Further, via hole electrodes Vh1 are formed in the third to seventh sheet layers 113 to 117 so as to penetrate the respective sheet layers 113 to 117.

The first to ninth sheet layers 111 to 11
Reference numeral 9 denotes, for example, a sheet obtained by kneading a dielectric ceramic mainly composed of barium oxide, aluminum oxide and silica, which can be fired at a temperature of 850 ° C. to 1000 ° C., together with a binder and the like.

The strip line electrodes ST11, S
T12, the capacitor electrodes Cp11 to Cp16 and the ground electrodes Gp11 and Gp12 are made of Ag, Pd, Ag-P
d, Cu, etc., the second to ninth sheet layers 112-1
It is formed on the surface of the substrate 19 by a known method such as a printing method, a sputtering method, and a vacuum evaporation method.

The first to ninth sheet layers 111 to 1
19 are stacked and integrally sintered,
The multilayer substrate 11 is obtained. Then, the strip line electrode S
T11 and capacitor electrodes Cp13 to Cp15, and stripline electrode ST12 and capacitor electrodes Cp12,
Cp16 is connected to via hole electrode Vh1 inside multilayer substrate 11.

On the side surface and the front and back surfaces of the multilayer substrate 11, a capacitor electrode Cp14 is electrically connected.
The external port T1 (FIG. 6) and the capacitor electrode Cp13 are electrically connected to the second port P1.
2 (FIG. 6) and a capacitor electrode C
electrically connected to p11, a third port P3 (FIG. 6)
External terminal T13 and the ground electrodes Gp11, Gp
12, an external terminal T14 serving as a ground terminal is formed. Note that these terminals T11 to T1
4 is formed by a method such as a sputtering method, a vacuum evaporation method, and a coating and baking method.

In the diplexer 10 having the above-described structure, the strip line electrodes ST11 and ST12 use the first
And the second inductors L1 and L2 (FIG. 6). Further, the first capacitor C11 (FIG. 6) and the capacitor electrode Cp1 are connected by the capacitor electrodes Cp13 and Cp14.
5 and the ground electrodes Gp11 and Gp12 form a first capacitor C12 (FIG. 6), respectively.

Further, the capacitor electrodes Cp12, Cp1
3, the second capacitor C21 (FIG. 6), the capacitor electrodes Cp11 and Cp12, the second capacitor C22 (FIG. 6), the capacitor electrode Cp16 and the ground electrode Gp1.
1 and Gp12 form a second capacitor C23 (FIG. 6).

That is, the second capacitor C2 connected in series between the second port P2 and the third port P3
1, C22 on a first capacitor C11 connected between the first port P1 and the second port P2;
In addition, the structure is such that the multilayer substrates 11 are stacked in the height direction.

FIG. 2 is a diagram showing a passing characteristic between the second and third ports of the diplexer of FIG. 2, the solid line shows the case of the diplexer 10 (FIG. 1) of the present embodiment, and the broken line shows the case of the diplexer 50 (FIG. 7) of the conventional example.

From this figure, it can be seen that in the high-pass filter between the second and third ports, the bandwidth of the diplexer 10 of this embodiment is wider than that of the conventional diplexer 50.

According to the diplexer of the first embodiment, the second capacitor connected in series between the second port and the third port is connected between the first port and the second port. The first capacitor is formed between the capacitor electrode forming the second capacitor and the ground electrode to be disposed on the first capacitor connected therebetween and to be stacked in the height direction of the multilayer substrate. Is inserted, and the stray capacitance generated between the capacitor electrode forming the second capacitor and the ground electrode can be suppressed. Therefore, no useless capacitance is generated in the high-pass filter between the second and third ports.
It is possible to widen the pass band of the high-pass filter.

FIG. 3 is an exploded perspective view of a second embodiment of the diplexer according to the present invention. The diplexer 20 includes first to first
A multilayer substrate 21 including ninth sheet layers 211 to 219 is provided. Capacitor electrodes Cp21 to Cp24 are formed on the upper surfaces of the second to fifth sheet layers 212 to 215, respectively. Strip line electrodes ST21 and ST22 are formed on the upper surfaces of the second and sixth sheet layers 212 and 216, respectively.

Further, the seventh and ninth sheet layers 217,
The ground electrodes Gp21 and Gp22 are formed on the upper surface of the 219, respectively. In addition, capacitor electrodes Cp25 and Cp26 are formed on the upper surface of the eighth sheet layer 218.
Further, via hole electrodes Vh2 are formed in the third to seventh sheet layers 213 to 217 so as to penetrate the respective sheet layers 213 to 217.

The first to ninth sheet layers 211 to 21
Reference numeral 9 denotes, for example, a sheet obtained by kneading a dielectric ceramic mainly composed of barium oxide, aluminum oxide and silica, which can be fired at a temperature of 850 ° C. to 1000 ° C., together with a binder and the like.

The strip line electrodes ST21, S
T22, the capacitor electrodes Cp21 to Cp26 and the ground electrodes Gp21 and Gp22 are made of Ag, Pd, Ag-P
d, Cu, etc., and the second to ninth sheet layers 212 to 2
It is formed on the surface of the substrate 19 by a known method such as a printing method, a sputtering method, and a vacuum evaporation method.

These first to ninth sheet layers 211 to 2
19 are stacked and integrally sintered,
The multilayer substrate 21 is obtained. Then, the strip line electrode S
T21 and the capacitor electrode Cp26, and the strip line electrode ST22 and the capacitor electrodes Cp23 to Cp25 are respectively formed inside the multilayer substrate 21 with the via hole electrode Vh.
2 is connected.

On the side surface and the front and back surfaces of the multilayer substrate 21, a capacitor electrode Cp24 is electrically connected.
The external port T1 (FIG. 6) and the capacitor electrode Cp23 are electrically connected to the second port P1.
2 (FIG. 6) and a capacitor electrode C
electrically connected to p21, a third port P3 (FIG. 6)
External terminal T23 and the ground electrodes Gp21, Gp
An external terminal T24 which is electrically connected to the terminal 22 and serves as a ground terminal is formed. Note that these terminals T21 to T2
4 is formed by a method such as a sputtering method, a vacuum evaporation method, and a coating and baking method.

In the diplexer 20 having the above configuration, the strip line electrodes ST21 and ST22 use the second
And first inductors L2 and L1 (FIG. 6). Further, the first capacitor C11 (FIG. 6) and the capacitor electrode Cp2 are connected by the capacitor electrodes Cp23 and Cp24.
5 and the ground electrodes Gp21 and Gp22 form a first capacitor C12 (FIG. 6), respectively.

Further, the capacitor electrodes Cp22, Cp2
3, the second capacitor C21 (FIG. 6), the capacitor electrodes Cp21 and Cp22, the second capacitor C22 (FIG. 6), the capacitor electrode Cp26 and the ground electrode Gp2.
1 and Gp22 form the second capacitor C23 (FIG. 6).

That is, the second capacitor C2 connected in series between the second port P2 and the third port P3
1, C22 forming capacitor electrodes Cp21-Cp2
3. A structure in which the first capacitor C11 connected between the first port P1 and the second port P2 is arranged on one capacitor electrode Cp24 forming the first capacitor C11 and is stacked in the height direction of the multilayer substrate 21 Has become.

The capacitor electrodes Cp23 to Cp25 forming the first capacitor C11 and the capacitor electrodes Cp21 to Cp forming the second capacitors C21 to C23 are formed.
In this structure, p23 and Cp26 are not disposed immediately above the strip line electrode ST21 forming the second inductor L2.

FIG. 4 is a diagram showing the passing characteristics between the second and third ports of the diplexer of FIG. In FIG. 4, the solid line is the diplexer 20 of the second embodiment (FIG. 3),
The broken line shows the case of the diplexer 10 (FIG. 1) of the first embodiment.

From this figure, it can be seen that in the high-pass filter between the second and third ports, the diplexer 20 of the second embodiment has a lower insertion loss in the pass band of 1.5 GHz or more than that of the first embodiment. It can be seen that the size is smaller than that of the diplexer 10.

According to the diplexer of the second embodiment, in addition to the structure of the first embodiment, the first and second capacitors are not arranged on the second inductor. The strip line electrode to be formed can be separated from the ground electrode.

Therefore, in addition to the effects of the first embodiment,
Since the impedance of the second inductor of the high-pass filter between the second and third ports can be increased,
The insertion loss can be reduced in the pass band of the high-pass filter.

FIG. 5 is a block diagram showing a part of the configuration of a general dual-band portable telephone which is one of the mobile communication devices, and shows 1.8 GHz band DCS and 900 MHz.
It shows an example in which GSM of a band is combined.
The dual-band mobile phone includes an antenna 1, a diplexer 2, and two signal paths GSM system 3 and DCS system 4.

The diplexer 2 combines transmission signals of the GSM system 3 or the DCS system 4 at the time of transmission and separates the received signal into the GSM system 3 or the DCS system 4 at the time of reception.

If the diplexers 10 and 20 (FIGS. 1 and 3) of the first and second embodiments are used as the diplexer 2, the pass band of the high-pass filter between the second and third ports of the diplexer can be obtained. And the insertion loss is reduced, so that it is possible to obtain a dual-band mobile phone having excellent transmission characteristics and reception characteristics.

In the above-described embodiment of the diplexer,
Although the case where the sheet layer is made of ceramics mainly containing barium oxide, aluminum oxide, and silica has been described,
Any material may be used as long as it has a relative dielectric constant (εr) of 1 or more. For example, similar effects can be obtained by using a ceramic containing magnesium oxide or silica as a main component, a fluororesin, or the like.

In the above-described dual-band portable telephone which is one of the mobile communication devices, the case where the combination is used for the combination of DCS and GSM has been described, but the use is limited to the combination of DCS and GSM. For example, PCS (Personal Communication Serv
ices) and AMPS (Advanced Mobile Phone Services), DECT (Digital European Cordless T)
elephone) and GSM, PHS (Personal H
andy-phone System) and PDC (Personal Digital Cellul
ar), and the like.

Although the case where there are two signal paths has been described, similar effects can be obtained when there are three or more signal paths.

[0046]

According to the diplexer of the first aspect, the second
A second capacitor connected in series between the first port and the third port is disposed on the first capacitor connected between the first port and the second port, and Since the capacitors are stacked in the height direction, one capacitor electrode forming the first capacitor is inserted between the capacitor electrode forming the second capacitor and the ground electrode, so that the capacitor forming the second capacitor is formed. The stray capacitance generated between the electrode and the ground electrode can be suppressed. Therefore, no useless capacitance is generated in the high-pass filter between the second and third ports, and the pass band of the high-pass filter can be expanded.

According to the diplexer of the present invention, since the first and second capacitors are not arranged on the second inductor, the strip line electrode forming the second inductor can be separated from the ground electrode. Therefore, the second high-pass filter between the second and third ports
Since the impedance of the inductor can be increased, the insertion loss can be reduced in the pass band of the high-pass filter.

According to the mobile communication device of the third aspect, the second
In addition, the use of a diplexer in which the high-pass filter between the third port and the high-pass filter has a wide pass band and a small insertion loss is used, so that it is possible to obtain a mobile communication device having excellent transmission characteristics and reception characteristics.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a first embodiment of a diplexer according to the present invention.

FIG. 2 is a diagram showing pass characteristics between second and third ports of the diplexer of FIG. 1;

FIG. 3 is an exploded perspective view of a second embodiment of the diplexer according to the present invention.

FIG. 4 is a diagram showing pass characteristics between second and third ports of the diplexer of FIG. 3;

FIG. 5 is a block diagram showing a part of the configuration of a general dual-band mobile phone (mobile communication device).

FIG. 6 is an equivalent circuit diagram of a general diplexer.

FIG. 7 is an exploded perspective view showing a conventional diplexer.

[Explanation of symbols]

10, 20 Diplexer 11, 21 Multilayer substrate 111 to 119, 211 to 219 Sheet layers C11, C12, C21 to C23 First and second capacitors Cp11 to Cp16, Cp21 to Cp26 Capacitor electrodes L1, L2 First and second Inductors P1 to P3 First to third ports ST11, ST12, ST21, ST22 Strip line electrodes

Continued on the front page (72) Inventor Takanori Ueshima 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Takahiro Watanabe 2-26-10 Tenjin, Nagaokakyo-shi Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Norio Nakajima 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Prefecture F-term in Murata Manufacturing Co., Ltd. (Reference) 5J006 HB05 HB13 HB21 HB22 HD08 JA03 JA04 JA11 KA01 KA11 KA13 LA02 LA05 LA13 NA04 NC03

Claims (3)

[Claims] A first inductor and a first capacitor that form a low-pass filter between the first and second ports; a second inductor and a first capacitor that form a low-pass filter between the first and second ports; A second inductor and a second capacitor that constitute a high-pass filter between the first and second inductors, and the first and second inductors are built in a multilayer substrate formed by laminating a plurality of ceramic sheet layers. Wherein the first and second capacitors are diplexers formed by capacitor electrodes built in the multilayer substrate, wherein the first and second capacitors are formed by a strip line electrode. The second capacitor connected in series to the first capacitor is disposed on the first capacitor connected between the first port and the second port, and is stacked in the height direction of the multilayer substrate. Diplexer, characterized in that the overlap. 2. The diplexer according to claim 1, wherein the first and second capacitors are not arranged on the second inductor. 3. A mobile communication device using the diplexer according to claim 1 or 2.