JP2003124710A - Irreversible circuit module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a irreversible circuit module, which is miniaturized and improves electric performance, especially, directivity. SOLUTION: This module has a permanent magnet for applying a DC magnetic field to a magnetic material, assembly, in which a plurality of central conductors with one terminal as a common terminal and the other terminal as an input/output terminal for high frequency signals is arranged on the magnetic material, a plurality of load capacitors laminated and formed on a laminate, in which a plurality of dielectric layers and conductor layers are laminated, irreversible circuit provided with a first resistor parallel connected with one of load capacitors, first transmission line connected to any one of central conductors, second transmission line electromagnetically coupled with the first transmission line, and directional coupling circuit provided with a second resistor serially connected to one terminal of the relevant second transmission line. Then, the first resistor is connected to a first ground electrode comprising one part of the ground side electrode of each of load capacitors, the second resistor is connected to a second ground electrode comprising another part of the ground side electrode of each of load capacitors, and the first ground electrode and the second ground electrode are arranged on the different layers of the laminate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonreciprocal circuit module in which a circulator and an isolator used in a microwave communication device such as a mobile phone are integrated with a directional coupler.

[0002]

2. Description of the Related Art The spread of wireless communication devices such as mobile phones is remarkable, and the functions and services of mobile phones are being improved. An example of such a mobile phone system is EGSM (Ex
tended Global System for Mobile Communications
) Method, DCS1800 (Digital Cellular Sys
tem 1800) system, PCS (Perso
There are various systems such as the nal Communications Service) system, the PDC (Personal Digital Cellular) system adopted in Japan, and the W-CDMA (Wide-band CDMA) system. It is stipulated that a transmission output control signal that regulates the transmission output should be sent to the telephone to control the transmission output power of the mobile station.

In addition, W-CDMA (Wide-band)
CDMA transmission frequency 1.92 GHz to 1.98 G
Hz, reception frequency 2.11 to 2.17 GHz, that is, code division multiple access (CDM) using spread spectrum.
In A) technology, in order to maximize the system capacity and improve the effective frequency utilization, the transmission power of the mobile station is set so that the radio waves of each mobile station arriving at the base station are always constant and at the same level. Wide variable range, eg 70-80d
It is necessary to finely and adaptively control in a wide range of B, and there is a great need for high efficiency and low power consumption not only at the maximum power but also when the transmission power is controlled to be low.

As such a wireless communication device, an example of a circuit block of a mobile phone, a car phone, etc. is shown in FIG.
In this example, the transmitting unit and the receiving unit are configured to be shared via the branching unit of one antenna. In this transmission unit, it is necessary to control the transmission output as described above, and a part of the transmission output power is reflected due to impedance variation of the antenna 6 or the like, and the power amplifier 1 may be damaged by this reflected power. , A signal of an adjacent channel may enter from the antenna 6 to cause intermodulation,
Measures are needed. Therefore, the modulation circuit unit (not shown)
The high-frequency signal transmitted from the power amplifier 1 and passed through the power amplifier 1 is passed through the directional coupler 2 to obtain an output proportional to the high-frequency signal, and the automatic gain control circuit 7
0 to control the output power of the power amplifier 1 and to arrange the isolator 3 on the rear side of the directional coupler 2 so that the low-pass filter 4 arranged on the rear side of the directional coupler 2 and the antenna are shared. The reflected wave generated by the mismatch of the line impedance and the characteristic impedance of each component such as the container 5 and the antenna 6 is prevented from entering the power amplifier 1.

There is a demand for miniaturization of a wireless communication device having such a circuit block, and especially in a mobile phone,
Directional coupler 2, low-pass filter 4, power amplifier 1
There is an increasing demand to reduce the area occupied by the product, reduce the price per function to reduce the price, and reduce the number of parts. In response to such requirements, the directional coupler 2, the nonreciprocal circuit device 3, the low-pass filter 4, and the power amplifier 1
Although it is possible to reduce the occupied area by reducing the size of each, there is a limit as a matter of course.

FIG. 9 is an exploded perspective view of a conventional non-reciprocal circuit device. This non-reciprocal circuit element is a central conductor (a conductor for applying signal power to and taking out signal power from ferrite, which is a magnetic material, and is used for signal input, signal output, and reflected wave absorption.
I have a book. ) Is a stripline center conductor 1 that radially extends in three directions from a ground electrode made of a thin copper plate.
A garnet-type ferrite magnetic body 13 is wrapped with 4a, 14b, and 14c, and these striplines are woven so that they are insulated from each other and intersect at the center 120 degrees to form an assembly 10, which is a dielectric that forms a load capacitance C1. It is placed in the hole 15 at the substantially central portion of the body substrate 11, and the input / output electrodes are soldered to the external electrodes on the upper surface of the dielectric substrate. Further, a metallic case 7 also serving as a yoke and a permanent magnet 9 for giving a DC magnetic field is arranged on the ferrite central conductor, and a magnetic circuit is constructed between the metallic case 8 on the lower side and a non-conductive case. It is a reversible circuit element.

In order to reduce the size of the non-reciprocal circuit device 3, the assembly 10 and the dielectric substrate 11 may simply be constructed in a small size. However, the miniaturization of the assembly 10 is optimal as a non-reciprocal circuit device. When the dielectric material with a high dielectric constant is used to obtain the required load capacity to deviate from the operating magnetic material size and to miniaturize the dielectric substrate, the dielectric material loss is relatively decreased. However, there is a problem that the electrical characteristics of the non-reciprocal circuit device are deteriorated.

As a small-sized directional coupler, there is a laminated directional coupler using the LTCC technology disclosed in Japanese Patent Laid-Open No. 9-214213. As such a laminated directional coupler, one having a size of 2.0 mm × 1.2 mm × 1.0 mm has already been developed. However, further miniaturization causes deterioration of isolation characteristics. As a result, the directivity, which is an important characteristic of the directional coupler, cannot be obtained. As a result, a part or all of the reflected wave opposite to the traveling direction of the transmission signal flows into the coupling output terminal, and the desired coupling degree is obtained. There was also a problem that I could not get it.

[0009]

Although miniaturization of the circuit element alone has various problems as described above, the present inventors have conventionally used the laminated dielectric substrate 11 which constitutes the load capacitance of the nonreciprocal circuit element. , LTCC technology was used to conceive the laminated directional coupler 2. FIG. 2 shows an example of an equivalent circuit when the non-reciprocal circuit device and the directional coupler are integrated into a non-reciprocal circuit module 20. Non-reciprocal circuit module 2
0 is between the port P4 of the non-reciprocal circuit 3 and the ground,
A first configuration in which the load capacitance C2 and the first resistor Ri are connected in parallel to configure the directional coupling circuit 2 at the port P3 of the nonreciprocal circuit 3.
Of the transmission line 200, and the second transmission line 201 is arranged so as to be electromagnetically coupled to the first transmission line 200, and one end of the second transmission line 201 is connected to the ground via the second resistor Rc. Consists of However, when the dielectric substrate 11 is simply laminated to form a laminated body, and the directional coupling circuit 2 is built into the nonreciprocal circuit module 20, sufficient isolation characteristics may not be obtained. Therefore, it is an object of the present invention to provide a non-reciprocal circuit module which is small in size and excellent in electrical performance, particularly in directionality, by integrally combining a non-reciprocal circuit and a directional coupling circuit.

[0010]

According to the present invention, a permanent magnet for applying a DC magnetic field to a magnetic body and a plurality of center conductors having one end as a common end and the other end as a high frequency signal input / output end are provided. An irreversible device having a plurality of load capacitors stacked in a stacked body in which a plurality of dielectric layers and conductor layers are stacked, and a first resistor connected in parallel with one of the load capacitors. A circuit, a first transmission line connected to any of the central conductors, a second transmission line electromagnetically coupled to the first transmission line, and a series connection to one end of the second transmission line. Second
And a directional coupling circuit having a resistor, the first resistor is connected to a first ground electrode forming a part of a ground side electrode of the load capacitance, and the second resistor is the load. A nonreciprocal circuit that is connected to a second ground electrode that forms another part of the ground side electrode of the capacitor, and the first ground electrode and the second ground electrode are arranged in different layers of the laminate. It is a module. In the present invention, the first ground electrode and the second ground electrode are electrically connected to each other by a via hole or a side surface electrode formed in the laminated body.

The isolation indicates the amount of a high frequency signal that appears at the port P5 of the directional coupling circuit when an unnecessary reflected wave is input to the port P3 from the antenna side as shown in FIG. The inventors of the present invention have diligently studied the influence of two paths, that is, a path 1 and a path 2 as such a reflected wave path. As a result, when the ground is unstable due to the structure of the laminated body, the directionality in the path 2 is increased. It has been found that the high frequency signal appearing at the port P5 of the coupling circuit increases.

The ground formed on the laminated body is formed by an electrode layer having a spread. In order to stabilize the ground, it is preferable to make the distribution of the high frequency current uniform in this electrode layer. As a means for this, it is preferable to connect to the ground of the circuit board on which the non-reciprocal circuit module is mounted by using a large number of via holes and external electrodes.However, using a large number of via holes induces deformation, cracks, or cracks of the laminated body. Cheap. Further, it is difficult to form a large number of external electrodes in a limited area, and it is difficult to obtain a stable ground. Therefore, in the present invention, a first ground electrode connected to the first resistor of the non-reciprocal circuit and a second ground electrode connected to the second resistor of the directional coupling circuit.
And the ground electrode of No. 1 were arranged in different layers of the laminate to stabilize the grounds of the nonreciprocal circuit and the directional coupling circuit.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment) An embodiment of the present invention will be described in detail below with reference to FIGS. FIG. 3 is an exploded perspective view of a non-reciprocal circuit module according to an embodiment of the present invention, and FIG. 4 is a development view of each layer of a laminated body 11 used in the non-reciprocal circuit module according to an embodiment of the present invention. This non-reciprocal circuit module has the functions of a non-reciprocal circuit and a directional coupler, and is an assembly 1 that is a part of the non-reciprocal circuit.
0 is, for example, a magnetic disk 13 such as a garnet arranged on a conductor having a structure in which three central conductors 14a, 14b, and 14c radially project from a disk-shaped grounding conductor, and the side surface of the disk. The center conductors are bent along with the center conductors 14a, 14b, and 14c so as to be sandwiched with an insulating film or the like between them, and the conductors are stacked at 120 degrees in an insulated state. As another example, the assembly 10 is formed by forming a magnetic material into a sheet by using a sheeting technique such as a doctor blade method, forming an electrode pattern serving as a central conductor on the magnetic material, stacking and integrating the magnetic material, and sintering. , A sintered magnetic body is formed by using a thin film technique to form a central conductor. The shape of the magnetic body is not particularly limited to a circular shape such as a rectangle or a polygon.

The assembly 10 is inserted into a recess 15 provided in the center of the laminate 11. Center conductors 14a-14
One end of c is a load capacitance C formed on the upper surface of the laminated body 11.
1 to C3 are connected to the electrode patterns 50a to 50c, and the other end of each central conductor is connected to the ground electrode (conductor plate) 18 of the resin base 12 via the ground electrode located on the lower surface of the garnet magnetic body 13. It Further assembly 10
The nonreciprocal circuit module of the present invention is constructed by arranging the permanent magnets 9 for applying a DC magnetic field to and surrounding them by the metal cases 7 and 8 which also function as magnetic yokes from above and below them.

The laminated body 11 is a ceramic dielectric material which can be fired at a low temperature, for example, a dielectric constant εr of about 8 and 900
A dielectric material that can be fired at ℃ is used. This as a binder,
A green sheet having a thickness of 30 μm to 100 μm is prepared by a doctor blade method as a slurry together with a solvent. A conductive paste mainly composed of a conductor such as Ag or Cu is printed on each green sheet to form the first and second transmission lines of the directional coupling circuit and the electrode pattern constituting the load capacitance of the nonreciprocal circuit. The green sheet can be manufactured by stacking these green sheets, integrating them, and sintering.

An example of the internal structure of the laminate 11 will be described in the order of lamination with reference to FIG. This laminated body 11 is a W-CD
MA (Wide-band CDMA transmission frequency =
It is used for a non-reciprocal circuit module of 1.92 GHz to 1.98 GHz). Note that, here, for simplification of description, a W-CDMA system is used as a system of a wireless communication device.
Taking the example as an example, the effect of the present invention does not change even with other systems.

First, on the uppermost green sheet a, electrode patterns 50a to 50c for load capacitors C1 to C3, electrode patterns 50d to 50g for connection, and through-hole electrodes (indicated by black circles in the figure) are formed. . And stack 1
Resistors Ri and Rc are formed on the upper surface of 1 by printing and baking. The resistor Ri is a nonreciprocal circuit resistor (first resistor), and the resistor Rc is a directional coupling circuit resistor (second resistor). A chip resistor may be used instead of the printing resistor, and each resistor may be formed by co-firing with the laminated body. On the lower layer of the green sheet a, the green sheet b having the line electrodes and the through-hole electrodes that form the first transmission line 200 is laminated, and then the electrode patterns 51a to 51 for the load capacitors.
c, the green sheet c on which the through-hole electrode is formed, the green sheet d on which the ground electrode 62 and the through-hole electrode are formed, the green sheet d on which the ground electrode 62 and the through-hole electrode are formed, and the second transmission line 20.
The green sheets e on which the line electrodes made of the conductor layers that form 1 are formed are sequentially laminated. On the back surface side f of the lowermost green sheet e, the ground electrode 63 is formed on almost the entire surface, and the electrode patterns 80a to 80c are connected to the connection electrodes 30a to 30c formed on the resin base 12.
Is provided. The electrode patterns 50a, 51a,
Electrode patterns 50b and 51b, electrode patterns 50c and 5
1c constitutes load capacitors C1 to C3 with the ground electrodes 61 and 62, respectively. The first resistor Ri is connected to the ground electrode 61 formed on the green sheet b via the through hole, and the second resistor Rc is connected to the ground electrode 62 formed on the green sheet d via the through hole.
Connected with. By thus configuring and arranging the second resistor Rc, which serves as an absorption resistance of the directional coupling circuit, on the lower surface side near the mounting surface in the stacked body, the grounds of the nonreciprocal circuit and the directional coupling circuit are stabilized. ing.

In this embodiment, the first and second
The line electrodes constituting the transmission lines 200 and 201 are coil-type coils each wound approximately one turn, and are vertically arranged 100 μm apart and face each other with a dielectric layer interposed therebetween, and the coupling degree is 20 dB. There is. Such a coil coupling type structure is preferable because the degree of coupling can be easily controlled by both the interlayer distance between the main line and the sub line and the line length of the overlapping portion. Of course, the line electrode may be wound one or more turns depending on the shape of the laminated body 11.

The impedance of the directional coupling circuit 2 is determined by the line width of the transmission line, the distance from the ground plane, and the like. Further, the impedance of the non-reciprocal circuit 3 is determined by the magnetic body 13 and the central conductor 14a that constitute the assembly 10.
.About.14c, which are determined by the magnetic characteristics of the permanent magnet 9, and are configured so as to have a desired characteristic impedance by appropriately selecting and adjusting them. The characteristic impedance of the directional coupling circuit 2 and the non-reciprocal circuit 3 is generally set at 50Ω, but when the directional coupler 2 and the non-reciprocal circuit element 3 are separately configured as in the conventional case. Then,
Manufacturing variations, such as variations in the thickness of the dielectric layer,
The characteristic impedance actually varies due to variations in the line width of the transmission line, variations in the magnetic material, and the like. Therefore, the directional coupler 2 and the non-reciprocal circuit device 3
When the above are combined individually as in the prior art, impedance mismatch occurs at the input / output terminal P2 and the insertion loss characteristic deteriorates. However, as in the present invention, the directional coupling circuit 2 is formed in the laminated body. Two transmission lines 20
0, 201 and load capacitors C1 to C that form the nonreciprocal circuit 3
If the three are integrated, the characteristic impedance of the non-reciprocal circuit 3 can be adjusted to the characteristic impedance of the directional coupling circuit 3 by adjusting the DC magnetic field of the permanent magnet 9, and substantially at the port P2. Impedance mismatch can be made extremely small. In addition, the load capacitances C1 to C3 are added to a laminated body in which a plurality of dielectric layers and conductor layers are laminated.
Since the first and second transmission lines 200 and 201 are laminated, the small nonreciprocal circuit module 20 can be realized.

A through hole 15 is formed in a substantially central portion of the laminated body 11 thus constructed, and the assembly 10 is accommodated therein. One end of the center conductor 14a is connected to an electrode pattern 50a which is a conductor layer forming a load capacitance formed on the upper surface of the laminated body 11, and the center conductor 14b is connected to the electrode pattern 5a.
0b and 50d, and one end of the center electrode 14c is connected to the electrode pattern 50c on the upper surface of the stack. The other end is connected to the ground electrode 18 (conductor plate) of the resin base 12 via the ground electrode located on the lower surface of the garnet 13. The external port 17 is provided on the side surface of the resin base 12.
a, 17b, 17c, 17d, 17e, 17f are formed, and the nonreciprocal circuit module is connected to the mounting substrate by this external port. With this structure, an ultra-small non-reciprocal circuit module having outer dimensions of 4 mm × 4 mm × 1.7 mm was manufactured.

As a comparative example, a nonreciprocal circuit module was prepared using the laminated body 11 shown in FIG. In this non-reciprocal circuit module, in the laminated body 11, the first resistor R
i, the second resistor Rc is connected to the ground electrode 61 formed on the green sheet b. Since the other structure is almost the same as that of the embodiment, its explanation is omitted.

FIG. 7 and FIG. 8 show coupling characteristics of an embodiment of the nonreciprocal circuit module of the present invention and its comparative example.
The isolation characteristic between the port P3 and the port P5 is shown. The non-reciprocal circuit module of the present invention can obtain an isolation characteristic of about 31 dB, while the non-reciprocal circuit module of the comparative example has about 22 dB, and by configuring as in the present invention, the output port P3 leaks to the coupling port P5. It can be seen that the high frequency signal can be extremely reduced. In addition, the directivity is 1.2 dB in the comparative example.
Although only about a certain degree can be obtained, the directionality of about 12.7 dB was obtained in the example, and the insertion loss was 0.5 dB, which was a low loss compared with 0.65 dB of the comparative example.

[0023]

According to the present invention, it is possible to provide a nonreciprocal circuit module which is small in size and excellent in electrical performance, particularly in directionality, by integrally combining a nonreciprocal circuit and a directional coupling circuit.

[Brief description of drawings]

FIG. 1 is a circuit block showing an example of a transmission unit of a wireless communication device.

FIG. 2 is an equivalent circuit according to an embodiment of a non-reciprocal circuit module of the present invention.

FIG. 3 is an exploded perspective view of an embodiment of the nonreciprocal circuit module of the present invention.

FIG. 4 is a development view of a laminate used in an example of the nonreciprocal circuit module of the present invention.

FIG. 5 is a development view of a laminated body of a non-reciprocal circuit module of a comparative example.

FIG. 6 is an equivalent circuit for explaining isolation characteristics.

FIG. 7 is a characteristic diagram according to an embodiment of the non-reciprocal circuit module of the present invention.

FIG. 8 is a characteristic diagram of a non-reciprocal circuit module of a comparative example.

FIG. 9 is an exploded perspective view of a conventional non-reciprocal circuit device.

[Explanation of symbols]

1 power amplifier Bidirectional coupler, directional coupling circuit 3 Non-reciprocal circuit element, non-reciprocal circuit 4 low pass filter 5 antenna duplexer 6 antenna 7 metal case 8 metal cases 9 Permanent magnet 10 assembly 11 laminate 12 Resin base 13 Magnetic material 14a to 14c Central conductor 15 recess 20 Non-reciprocal circuit module 50a-50c electrode pattern 51a to 51c electrode pattern 52a to 52c electrode pattern 60,61 ground electrode 100-105 green sheets 200 First transmission line 201 Second transmission line

Claims (2)

[Claims] 1. An assembly in which a permanent magnet for applying a DC magnetic field to a magnetic body and a plurality of center conductors having one end as a common end and the other end as a high-frequency signal input / output end are arranged on the magnetic body, Any of the nonreciprocal circuit having a plurality of load capacitors laminated in a laminated body in which the dielectric layer and the conductor layer are laminated, a first resistor connected in parallel with one of the load capacitors, and the central conductor. Direction including a first transmission line connected to the second transmission line, a second transmission line electromagnetically coupled to the first transmission line, and a second resistor connected in series to one end of the second transmission line. A capacitive coupling circuit, the first resistor is connected to a first ground electrode forming a part of a ground side electrode of the load capacitance, and the second resistor is connected to a ground side electrode of the load capacitance. Is connected to a second ground electrode forming another part, and is connected to the first ground The nonreciprocal circuit module, wherein the electrode and the second ground electrode are arranged in different layers of the laminate. 2. The first ground electrode and the second ground electrode are electrically connected to each other by a via hole or a side surface electrode formed in the laminated body. Non-reciprocal circuit module.