JP4378793B2 - Diplexer and mobile communication device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a diplexer and a mobile communication device using the diplexer, and more particularly to a diplexer that separates and synthesizes high frequency signals having different frequencies and a mobile communication device using the diplexer.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a diplexer that can separate and synthesize high-frequency signals with different frequencies in order to support high-frequency signals with different frequencies using a single antenna, such as GSM (Global System for Mobile communications) and DCS (Digital Cellular System). It is used.
[0003]
FIG. 6 is an equivalent circuit diagram of a general diplexer. The diplexer includes first to third ports P1 to P3, a low-pass filter LPF between the first and second ports, 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. From the first inductor L11 and the first capacitor C11 between the first port P1 and the second port P2. The 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 second capacitors C21 and C22 are connected in series between the second port P2 and the third port P3. A series circuit including the second inductor L2 and the second capacitor C23 is connected between the connection point of the second capacitors C21 and C22 and the ground.
[0004]
FIG. 7 is an exploded perspective view of a conventional diplexer. The diplexer 50 includes a multilayer substrate 51 including first to seventh sheet layers 511 to 517. Capacitor electrodes Cp51 and Cp52, capacitor electrodes Cp53 and Cp54, and capacitor electrodes Cp55 and Cp56 are formed on the upper surfaces of the second, third and sixth sheet layers 512, 513 and 516, respectively. Further, stripline electrodes ST51 and ST52 are formed on the upper surface of the fourth sheet layer 514. Further, a ground electrode Gp51 and a ground electrode Gp52 are formed on the upper surfaces of the fifth and seventh sheet layers 515 and 517, respectively. In addition, via hole electrodes Vh5 are formed in the second to fifth sheet layers 512 to 515 so as to penetrate the respective sheet layers 512 to 515.
[0005]
The first to seventh sheet layers 511 to 517 are stacked and integrally sintered to form the multilayer substrate 51. The stripline electrode ST51 and the capacitor electrodes Cp51, Cp53, and Cp55, and the stripline electrode ST52 and the capacitor electrodes Cp54 and Cp56 are connected to each other through the via hole electrode Vh5 inside the multilayer substrate 51. Further, the side and front and back surfaces of the multilayer substrate 51 are electrically connected to the capacitor electrode Cp51, and are connected to the external terminals T51 and T52 serving as the first and second ports P1 and P2 (FIG. 6) and the capacitor electrode Cp52. An external terminal T53 which is electrically connected and becomes the third port P3 (FIG. 6) and an external terminal T54 which is electrically connected to the ground electrodes Gp51 and Gp52 and becomes the ground terminal are formed.
[0006]
In the diplexer 50 having the above configuration, the first and second inductors L1 and L2 (FIG. 6) are formed by the stripline electrodes ST51 and ST52, respectively. The capacitor electrodes Cp51 and Cp53 form the first capacitor C11 (FIG. 6), and the capacitor electrode Cp55 and the ground electrodes Gp51 and Gp52 form the first capacitor C12 (FIG. 6). Furthermore, the capacitor electrode Cp51, Cp54 is the second capacitor C21 (FIG. 6), the capacitor electrode Cp52, Cp54 is the second capacitor C22 (FIG. 6), the capacitor electrode Cp56 and the ground electrode Gp51, Gp52 are the second capacitor C23. (FIG. 6) is formed.
[0007]
[Problems to be solved by the invention]
However, according to the above conventional diplexer, in the high-pass filter between the second and third ports, the second capacitor connected in series is formed between the second port and the third port. A stray capacitance is generated between the capacitor electrode and the ground electrode, and in the equivalent circuit, a capacitor as shown by a broken line in FIG. 6 is added. 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 has been a problem that the pass band of the high-pass filter between the second and third ports becomes narrow and the insertion loss increases.
[0008]
The present invention has been made to solve such problems, and a diplexer having a structure that widens the passband of a high-pass filter between the second and third ports and reduces insertion loss, and An object is to provide a mobile communication device using the same.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, a diplexer according to the present invention includes first to third ports, a first inductor and a first capacitor constituting a low-pass filter between the first and second ports, A second inductor and a second capacitor constituting a high-pass filter between the second and third ports, and the first and second inductors include a plurality of sheet layers made of ceramics. A diplexer formed by strip line electrodes built in a multilayer substrate formed by stacking, wherein the first and second capacitors are formed by capacitor electrodes built in the multilayer substrate, and the second port the first con plurality of said second capacitor, connected in series between said first port and a second port connected in series between said third port and Placed directly on the capacitors, and wherein the stacking height direction of the multilayer substrate.
[0010]
Further, a capacitor connected in series between said first and second and between the second port and the third port with the second port and the first port of the capacitor, the characterized in that in the laminating direction of the multilayer substrate is not disposed directly above the second inductor.
[0011]
The mobile communication device of the present invention is characterized by using the above diplexer.
[0012]
According to the diplexer of the present invention, the second capacitor connected in series between the second port and the third port is connected to the first capacitor connected between the first port and the second port. In order to arrange on the capacitor and to stack in the height direction of the multilayer substrate, the capacitor electrode forming the first capacitor is inserted between the capacitor electrode forming the second capacitor and the ground electrode, It is possible to suppress stray capacitance generated between the capacitor electrode forming the second capacitor and the ground electrode.
[0013]
According to the mobile communication device of the present invention, since the passband of the high-pass filter between the second and third ports is widened and the diplexer with a small insertion loss is used, the transmission characteristic and the reception characteristic are excellent. A mobile communication device can be obtained.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an exploded perspective view of a first embodiment of a diplexer according to the present invention. The diplexer 10 includes a multilayer substrate 11 composed of first to ninth sheet layers 111 to 119. Capacitor electrodes Cp11 to Cp14 are formed on the top surfaces of the second to fifth sheet layers 112 to 115, respectively. Further, stripline electrodes ST11 and ST12 are formed on the upper surface of the sixth sheet layer 116.
[0015]
Further, ground electrodes Gp11 and Gp12 are formed on the upper surfaces of the seventh and ninth sheet layers 117 and 119, respectively. Capacitor electrodes Cp15 and Cp16 are formed on the upper surface of the eighth sheet layer 118. Further, a via-hole electrode Vh1 is formed in the third to seventh sheet layers 113 to 117 so as to penetrate each of the sheet layers 113 to 117.
[0016]
The first to ninth sheet layers 111 to 119 are, for example, kneaded with dielectric ceramics mainly composed of barium oxide, aluminum oxide, and silica that can be fired at a temperature of 850 ° C. to 1000 ° C. together with a binder. Things are made into sheets.
[0017]
The strip line electrodes ST11 and ST12, the capacitor electrodes Cp11 to Cp16, and the ground electrodes Gp11 and Gp12 are made of Ag, Pd, Ag-Pd, Cu, etc., and are formed on the surfaces of the second to ninth sheet layers 112 to 119, respectively. It is formed by a known method such as printing, sputtering, or vacuum deposition.
[0018]
The first to ninth sheet layers 111 to 119 are stacked and integrally sintered to form the multilayer substrate 11. The strip line electrode ST11 and the capacitor electrodes Cp13 to Cp15, and the strip line electrode ST12 and the capacitor electrodes Cp12 and Cp16 are connected to each other via the via hole electrode Vh1 inside the multilayer substrate 11.
[0019]
Further, the side surface and the front and back surfaces of the multilayer substrate 11 are electrically connected to the capacitor electrode Cp14, and are electrically connected to the external terminal T11 serving as the first port P1 (FIG. 6) and the capacitor electrode Cp13. 2 is electrically connected to the external terminal T12 serving as the port P2 (FIG. 6) and the capacitor electrode Cp11, and is electrically coupled to the external terminal T13 serving as the third port P3 (FIG. 6) and the ground electrodes Gp11 and Gp12. An external terminal T14 that is connected and serves as a ground terminal is formed. In addition, these terminals T11-T14 are formed by methods, such as sputtering method, a vacuum evaporation method, and application | coating baking.
[0020]
In the diplexer 10 having the above configuration, the first and second inductors L1 and L2 (FIG. 6) are formed by the stripline electrodes ST11 and ST12, respectively. The capacitor electrodes Cp13 and Cp14 form the first capacitor C11 (FIG. 6), and the capacitor electrode Cp15 and the ground electrodes Gp11 and Gp12 form the first capacitor C12 (FIG. 6).
[0021]
Furthermore, the capacitor electrode Cp12, Cp13 is the second capacitor C21 (FIG. 6), the capacitor electrode Cp11, Cp12 is the second capacitor C22 (FIG. 6), the capacitor electrode Cp16 and the ground electrode Gp11, Gp12 are the second capacitor C23. (FIG. 6) is formed.
[0022]
That is, the second capacitors C21 and C22 connected in series between the second port P2 and the third port P3 are connected to the first capacitor connected between the first port P1 and the second port P2. It is arranged on the capacitor C11 and stacked in the height direction of the multilayer substrate 11.
[0023]
FIG. 2 is a diagram showing pass characteristics between the second and third ports of the diplexer of FIG. In FIG. 2, the solid line indicates the case of the diplexer 10 (FIG. 1) of the present embodiment, and the broken line indicates the case of the diplexer 50 (FIG. 7) of the conventional example.
[0024]
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 diplexer 50 of the conventional example.
[0025]
According to the diplexer of the first embodiment described above, the second capacitor connected in series between the second port and the third port is connected between the first port and the second port. One capacitor electrode that forms the first capacitor between the capacitor electrode that forms the second capacitor and the ground electrode is disposed on the first capacitor and stacked in the height direction of the multilayer substrate. Therefore, stray capacitance generated between the capacitor electrode forming the second capacitor and the ground electrode can be suppressed. Therefore, no unnecessary capacity is generated in the high-pass filter between the second and third ports, and the pass band of the high-pass filter can be widened.
[0026]
FIG. 3 is an exploded perspective view of a second embodiment of the diplexer of the present invention. The diplexer 20 includes a multilayer substrate 21 composed of first to ninth sheet layers 211 to 219. Capacitor electrodes Cp21 to Cp24 are formed on the top surfaces of the second to fifth sheet layers 212 to 215, respectively. Further, stripline electrodes ST21 and ST22 are formed on the upper surfaces of the second and sixth sheet layers 212 and 216, respectively.
[0027]
Further, ground electrodes Gp21 and Gp22 are formed on the upper surfaces of the seventh and ninth sheet layers 217 and 219, respectively. Capacitor electrodes Cp25 and Cp26 are formed on the upper surface of the eighth sheet layer 218. Further, via hole electrodes Vh <b> 2 are formed in the third to seventh sheet layers 213 to 217 so as to penetrate the sheet layers 213 to 217.
[0028]
The first to ninth sheet layers 211 to 219 are, for example, kneaded dielectric ceramics 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. Things are made into sheets.
[0029]
The strip line electrodes ST21 and ST22, the capacitor electrodes Cp21 to Cp26, and the ground electrodes Gp21 and Gp22 are made of Ag, Pd, Ag-Pd, Cu, or the like, and are formed on the surfaces of the second to ninth sheet layers 212 to 219. It is formed by a known method such as printing, sputtering, or vacuum deposition.
[0030]
The first to ninth sheet layers 211 to 219 are stacked and integrally sintered to form the multilayer substrate 21. The stripline electrode ST21 and the capacitor electrode Cp26, and the stripline electrode ST22 and the capacitor electrodes Cp23 to Cp25 are connected to each other through the via-hole electrode Vh2 inside the multilayer substrate 21.
[0031]
Further, the side surface and the front and back surfaces of the multilayer substrate 21 are electrically connected to the capacitor electrode Cp24, and are electrically connected to the external terminal T21 serving as the first port P1 (FIG. 6) and the capacitor electrode Cp23. 2 is electrically connected to the external terminal T22 serving as the port P2 (FIG. 6) and the capacitor electrode Cp21, and is electrically coupled to the external terminal T23 serving as the third port P3 (FIG. 6) and the ground electrodes Gp21 and Gp22. An external terminal T24 that is connected and serves as a ground terminal is formed. In addition, these terminals T21-T24 are formed by methods, such as sputtering method, a vacuum evaporation method, and application | coating baking.
[0032]
In the diplexer 20 having the above configuration, the second and first inductors L2 and L1 (FIG. 6) are formed by the stripline electrodes ST21 and ST22, respectively. The capacitor electrodes Cp23 and Cp24 form a first capacitor C11 (FIG. 6), and the capacitor electrode Cp25 and the ground electrodes Gp21 and Gp22 form a first capacitor C12 (FIG. 6).
[0033]
Further, the capacitor electrode Cp22, Cp23 is the second capacitor C21 (FIG. 6), the capacitor electrode Cp21, Cp22 is the second capacitor C22 (FIG. 6), the capacitor electrode Cp26 and the ground electrode Gp21, Gp22 are the second capacitor C23. (FIG. 6) is formed.
[0034]
That is, the capacitor electrodes Cp21 to Cp23 forming the second capacitors C21 and C22 connected in series between the second port P2 and the third port P3, and the first port P1 and the second port P2 It is arranged on one capacitor electrode Cp24 that forms the first capacitor C11 connected between them, and is stacked in the height direction of the multilayer substrate 21.
[0035]
The capacitor electrodes Cp23 to Cp25 forming the first capacitor C11 and the capacitor electrodes Cp21 to Cp23 and Cp26 forming the second capacitors C21 to C23 are directly above the stripline electrode ST21 forming the second inductor L2. The structure is not arranged.
[0036]
FIG. 4 is a diagram illustrating pass characteristics between the second and third ports of the diplexer of FIG. In FIG. 4, the solid line represents the diplexer 20 (FIG. 3) of the second embodiment, and the broken line represents the diplexer 10 (FIG. 1) of the first embodiment.
[0037]
From this figure, in the high-pass filter between the second and third ports, the insertion loss in the pass band of 1.5 GHz or more is higher in the diplexer 20 of the second embodiment than in the diplexer 20 of the second embodiment. It can be seen that it is smaller than.
[0038]
According to the above-described diplexer of the second embodiment, the first and second capacitors are not arranged on the second inductor in addition to the structure of the first embodiment, so that the strip forming the second inductor is formed. The line electrode can be separated from the ground electrode.
[0039]
Therefore, in addition to the effect 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, insertion loss is reduced in the pass band of the high-pass filter. It can be made smaller.
[0040]
FIG. 5 is a block diagram showing a part of a configuration of a general dual-band mobile phone which is one of mobile communication devices, and an example in which a 1.8 GHz band DCS and a 900 MHz band GSM are combined. It is shown. The dual-band portable telephone device includes an antenna 1, a diplexer 2, and two signal paths GSM system 3 and DCS system 4.
[0041]
The diplexer 2 combines the transmission signals of the GSM system 3 or the DCS system 4 at the time of transmission, and plays a role of separating the received signals into the GSM system 3 or the DCS system 4 at the time of reception.
[0042]
If the diplexers 10 and 20 (FIGS. 1 and 3) of the first and second embodiments are used for the diplexer 2, the pass band of the high-pass filter between the second and third ports of the diplexer is widened. At the same time, since the insertion loss is reduced, a dual-band mobile phone having excellent transmission characteristics and reception characteristics can be obtained.
[0043]
In the embodiment of the diplexer, the case where the sheet layer is a ceramic mainly composed of barium oxide, aluminum oxide, and silica has been described. However, any material may be used as long as the relative dielectric constant (εr) is 1 or more. For example, the same effect can be obtained with ceramics or fluorine-based resin mainly composed of magnesium oxide and silica.
[0044]
In the dual band mobile phone which is one of the mobile communication devices described above, the case where it is used for the combination of DCS and GSM has been described, but the use is not limited to the combination of DCS and GSM. For example, a combination of PCS (Personal Communication Services) and AMPS (Advanced Mobile Phone Services), a combination of DECT (Digital European Cordless Telephone) and GSM, PHS (Personal Handy-phone System) and PDC (Personal Digital Cellular) Can be used in combination with.
[0045]
Moreover, although the case where it has 2 signal paths was demonstrated, the same effect is acquired also when it has 3 or more signal paths.
[0046]
【The invention's effect】
According to the diplexer of claim 1, the second capacitor connected in series between the second port and the third port is connected to the first capacitor connected between the first port and the second port. One capacitor electrode that forms the first capacitor is inserted between the capacitor electrode that forms the second capacitor and the ground electrode so as to be disposed on the capacitor and stacked in the height direction of the multilayer substrate. In other words, stray capacitance generated between the capacitor electrode forming the second capacitor and the ground electrode can be suppressed. Therefore, no unnecessary capacity is generated in the high-pass filter between the second and third ports, and the pass band of the high-pass filter can be widened.
[0047]
According to the diplexer of the second aspect, since the first and second capacitors are not arranged on the second inductor, the stripline electrode forming the second inductor can be separated from the ground electrode. Accordingly, 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.
[0048]
According to the mobile communication device of claim 3, since the passband of the high-pass filter between the second and third ports is widened and the diplexer with small insertion loss is used, the transmission characteristic and the reception characteristic are excellent. A mobile communication device can be obtained.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a first embodiment according to a diplexer of the present invention.
FIG. 2 is a diagram illustrating pass characteristics between second and third ports of the diplexer of FIG. 1;
FIG. 3 is an exploded perspective view of a second embodiment according to the diplexer of the present invention.
4 is a diagram illustrating pass characteristics between the second and third ports of the diplexer of FIG. 3; FIG.
FIG. 5 is a block diagram showing a part of a 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 Diplexers 11, 21 Multilayer substrates 111-119, 211-219 Sheet layers C11, C12, C21-C23 First and second capacitors Cp11-Cp16, Cp21-Cp26 Capacitor electrodes L1, L2 First and second Inductors P1 to P3 First to third ports ST11, ST12, ST21, ST22 Stripline electrodes

Claims (2)

High pass between the first and third ports, a first inductor and a first capacitor constituting a low pass filter between the first and second ports, and the second and third ports A second inductor and a second capacitor constituting the filter;
The first and second inductors are formed by stripline electrodes built in a multilayer board formed by laminating a plurality of sheet layers made of ceramics, and the first and second capacitors are built in the multilayer board. A diplexer formed by a capacitor electrode,
A plurality of the second capacitors connected in series between the second port and the third port are connected to the first capacitor connected in series between the first port and the second port . diplexer, characterized in that arranged on the straight, and stacked in the height direction of the multilayer substrate. Among the first and second capacitors , a capacitor connected in series between the first port and the second port and between the second port and the third port is connected to the multilayer substrate. diplexer according to claim 1, characterized in that in the stacking direction is not arranged immediately above said second inductor.

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