JP6224484B2 - Directional coupler and high frequency module - Google Patents

Description

  The present invention relates to a directional coupler including a laminate formed by laminating a plurality of insulating layers, and a main line and a sub-line provided in the insulating layer so as to face each other with the insulating layer interposed therebetween, and The present invention relates to a high-frequency module including a directional coupler.

  In recent years, mobile phones have increasingly adopted a so-called multi-band system in which two or more transmission / reception systems are installed. A multiband mobile phone needs to be equipped with a circuit necessary for the configuration of each transmission / reception system, but the circuit becomes complicated. Further, if a circuit is configured using individual dedicated parts, the size of the device (cell phone, etc.) and the cost increase will be caused. For this reason, high frequency modules that integrate circuit components such as transmission / reception filter elements are also being developed. In this high frequency module, a directional coupler is used as a substrate or a single component for electrically connecting a plurality of circuit components.

  As described above, directional couplers are frequently used as components connected to elements that transmit high-frequency signals such as filter elements. The directional coupler includes a main line through which a high-frequency signal is transmitted, and a sub line that is electromagnetically coupled to the main line. The main line and the sub line are provided in a laminated body in which a plurality of insulating layers are laminated. For example, the main line and the sub line are electromagnetically coupled to each other by vertically opposing the main line and the sub line with an insulating layer interposed therebetween.

  In such a directional coupler, the main line and the sub line are adjusted to a general impedance value (usually 50Ω) in the high frequency line. For example, a signal for sending back (feeding back) electrical information to an element to which the main line is connected is transmitted to the sub line.

JP-A-10-126117

  In the directional coupler described above, in recent years, there are cases in which the directional coupler is electrically connected to a circuit (circuit component) different from the impedance value. For example, the sub line is connected to a semiconductor element having a relatively low impedance value (about 20Ω). In this case, a separate impedance conversion circuit is provided between the directional coupler and the semiconductor element.

  However, when such an impedance conversion circuit is provided, there is a problem that it is difficult to reduce the size as a high-frequency module including a directional coupler and circuit components.

A directional coupler according to an aspect of the present invention includes a plurality of insulating layers stacked on each other, a stacked body having a first main surface and a second main surface facing each other, and the above-described stacked body A pair of ground conductor layers provided on the first main surface and the second main surface and facing each other across the multilayer body; and the first main surface and the second main surface between the pair of ground conductor layers inside the multilayer body. A circuit including a main line and a sub line which are provided in order from one main surface side and face each other with a part of the plurality of insulating layers interposed therebetween, and the main line has a first impedance value And a line portion electrically connected to each other. The sub-line includes a low-impedance connection portion that is electrically connected to a low-impedance circuit having a second impedance value lower than the first impedance value. the distance between the connection part to your Keru said ground conductor layer provided on the second major surface and said sub-line, between said first major surface to the ground conductor layer provided the main line Less than distance.

  The high-frequency module according to one aspect of the present invention includes the directional coupler having the above-described configuration and a circuit to which the coupler is electrically connected.

  According to the directional coupler of one aspect of the present invention, the distance between the sub line and the ground conductor layer is smaller than the distance between the main line and the ground conductor layer. Therefore, a larger capacitance is generated between the sub-line and the ground conductor layer, particularly in the low impedance connection portion. As a result, the impedance value of the sub line at the connection portion can be made lower than the impedance value of the signal line including the main line, and the impedance value between the directional coupler and the element having a low impedance circuit such as a semiconductor element. Are aligned. Therefore, it is possible to provide a directional coupler that does not require an impedance matching circuit or the like and can be easily downsized, such as a high-frequency module.

  Since the high-frequency module according to one aspect of the present invention includes the directional coupler configured as described above, it is advantageous in downsizing.

It is sectional drawing which shows the principal part in the directional coupler of embodiment of this invention. It is a circuit diagram which shows typically the principal part in the high frequency module containing the directional coupler shown in FIG. It is a disassembled perspective view which shows the modification of the directional coupler shown in FIG.

  The directional coupler and high-frequency module of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a main part of a directional coupler according to an embodiment of the present invention. FIG. 2 is a circuit diagram schematically showing a main part of the high-frequency module including the directional coupler shown in FIG. The impedance in the following description is a characteristic impedance.

  In the directional coupler 9 shown in FIG. 1, a plurality of insulating layers 2 are stacked to form a stacked body 1. The laminated body 1 has, for example, a rectangular plate shape, and has a first main surface and a second main surface that face each other. In the example of FIG. 1, the upper surface of the laminate 1 is a first main surface, and the lower surface is a second main surface. A pair of ground conductor layers 3 are provided on both the first and second main surfaces of the multilayer body 1 so as to face each other with the multilayer body 1 interposed therebetween. Moreover, the main line 4 and the subline 5 are provided in the laminated body 1 in order from the first main surface side. The main line 4 and the sub line 5 face each other with a part of the insulating layer 2 interposed therebetween, and are electromagnetically coupled to each other. The main line 4 and the sub line 5 are electrically connected to an external circuit (electric circuit) to form a line portion 6 through which signals are transmitted.

  The laminated body 1 functions as an insulating base for providing the main line 4 and the sub line 5 in a state of being electrically insulated from each other. In addition to the laminate 1, this insulating substrate may include additional portions (not shown) such as other insulating layers or coating layers.

Examples of the other insulating layer as the additional portion include those having different characteristics from the insulating layer 2 such as electrical characteristics such as relative permittivity or relative permeability, or thermal characteristics such as thermal conductivity. Further, the insulating layer or the like as an additional portion may be an insulating coating layer (not shown) for protecting the ground conductor layer 3 from the outside air and suppressing oxidation or the like. That is, the directional coupler according to the embodiment may be one in which the ground conductor layer 3, the main line 4, and the sub line 5 are provided on an insulating substrate (not shown) including the multilayer body 1 and the additional portion. Good.

  The insulating layer 2 is made of, for example, a ceramic sintered body such as an aluminum oxide sintered body, a glass ceramic sintered body, an aluminum nitride sintered body, a mullite sintered body, a silicon nitride sintered body, or a silicon carbide sintered body. It is made of a binder.

  For example, when each insulating layer 1 is made of a glass ceramic sintered body, the laminate 1 is manufactured as follows. First, a slurry is prepared by adding and mixing an appropriate organic binder, a solvent, and the like to a raw material powder made of glass powder such as borosilicate glass and ceramic powder such as aluminum oxide. Next, a plurality of ceramic green sheets are produced by forming the slurry into a sheet by a forming method such as a doctor blade method. Thereafter, the ceramic green sheets are formed into an appropriate shape by cutting or punching and are laminated. Finally, the laminated body 1 can be manufactured by firing the laminated ceramic green sheets at a temperature of about 900 to 1000 ° C. in a reducing atmosphere.

  The pair of ground conductor layers 3 provided on both the first and second main surfaces of the multilayer body 1 has a function of reducing electromagnetic noise transmission and reception between the line portion 6 and the outside. These ground conductor layers 3 have a function of adjusting the impedance of the line portion 6 to a predetermined value. Capacitance is generated between each of the main line 4 and the sub line 5 and the ground conductor layer 3, and the impedance value of the main line 4 and the sub line 5 is adjusted to a predetermined value according to the magnitude of the electrostatic capacity. Has been.

  The ground conductor layer 3 is formed of, for example, a metal material such as copper, silver, palladium, platinum, tungsten, molybdenum, or manganese, or an alloy metal material containing these metal materials. These metal materials are provided on both main surfaces of the laminate 1 in the form of a metallized layer or a plating layer.

  If the ground conductor layer 3 is made of, for example, a copper metallized layer, a metal paste 1 prepared by kneading copper powder together with an organic solvent and a binder is used as a predetermined ceramic green sheet for the laminate 1. It can be made to adhere to both the 1st and 2nd main surfaces of the laminated body 1 by printing on a site | part by methods, such as screen printing, and baking.

  In the present embodiment, the ground conductor layer 3 is provided so as to cover substantially the entire area of the first and second main surfaces of the multilayer body 1 (so-called solid shape). Thereby, the functions for electromagnetic shielding or impedance value adjustment as described above are effectively realized.

  However, the ground conductor layer 3 does not necessarily have to be provided so as to cover almost the entire area of the first and second main surfaces of the multilayer body 1, and the position of other conductors such as connection terminals described later. In accordance with reduction of deformation such as warpage during firing of the laminate 1 or other design convenience, or productivity, economy, etc., a non-formed portion (so-called pattern-extracted portion) is appropriately provided. It does not matter.

  For example, as shown in FIG. 2, the directional coupler 9 has both ends of the line portion 6 electrically connected to the connection terminal 7, and the switch (SW), filter element, antenna ( AN) or a circuit included in a circuit component such as a semiconductor integrated circuit element (IC). The directional coupler 9 and the circuit included in the circuit component form the high frequency module 10 according to the embodiment of the present invention. The connection circuit for electrically connecting the circuit component and the directional coupler is normally set to 50Ω.

  In the high-frequency module, the directional coupler 9 and the circuit components are mounted on a substrate such as a printed circuit board. Further, the circuit such as the switch, the filter element, and the antenna may be constituted by an electric circuit directly provided on the substrate. That is, the board on which the directional coupler 9 is mounted may have a circuit that functions as a switch or a filter and a circuit that connects circuit components mounted on the board. The electrical connection between the directional coupler 9 and the circuit components and the substrate is performed, for example, by connecting the respective connecting portions with a conductive connecting material such as solder.

  The high-frequency module is a part that integrally configures a multiband circuit in a mobile phone, for example. By using such a high-frequency module as a component, it becomes easier to reduce the size and increase the functionality of a device such as a mobile phone.

  In the directional coupler 9 and the high-frequency module 10 of the embodiment, the sub line 5 is electrically connected to a low impedance circuit having a second impedance value lower than 50Ω that is the first impedance value. The low impedance circuit in the present embodiment is an IC circuit to which the sub line 5 is electrically connected, for example, a circuit of about 20Ω. That is, the sub line 5 includes a low impedance connection part (hereinafter also simply referred to as a connection part) connected to the low impedance circuit.

  In the connection portion of the sub line 5, the distance between the ground conductor layer 3 provided on the second main surface and the sub line 5 is such that the ground conductor layer 3 provided on the first main surface and the main line 4 are Less than the distance between. In other words, when the plurality of insulating layers 2 have the same thickness, the number of insulating layers 2 between the ground conductor layer 3 and the sub line 5 provided on the second main surface is the first main layer. The number is smaller than the number of insulating layers 2 between the ground conductor layer 3 and the main line 4 provided on the surface. In the following description, the distance between the ground conductor layer 3 provided on the first (2) main surface and the main (secondary) line 4 (5) is simply referred to as the ground conductor layer 3 and the main (secondary) line. It is called the distance between the track 4 (5).

  According to the directional coupler 9 as described above, the distance between the sub line 5 and the ground conductor layer 3 is smaller than the distance between the main line 4 and the ground conductor layer 3. Of these, a larger capacitance is generated between the ground conductor layer 3 and the connection portion. Thereby, the impedance value of the sub line 5 in the connection part can be made lower than the impedance value of the line part 6 including the main line 4. Therefore, the impedance value is matched between the directional coupler 9 and an element having a low impedance circuit such as an IC. Therefore, it is possible to provide a directional coupler that does not require an impedance matching circuit or the like and that facilitates downsizing of the high-frequency module 10.

  In addition, since it is easy to enhance functions such as a filter function of the high-frequency module, it is advantageous in enhancing the function.

  Moreover, since the high frequency module 10 of the embodiment includes the directional coupler 9 that is advantageous for downsizing as described above, it is advantageous for downsizing and the like.

  In addition, the more specific function of the line part 6 in said directional coupler 9 and the high frequency module 10 is as follows, for example.

  The main line 4 is a signal line for inputting, for example, a high-frequency signal amplified by a power amplifier and outputting it to a switch for switching transmission / reception or a communication band, a filter for removing harmonics, etc. of the high-frequency signal. The signal output from the directional coupler is filtered to a predetermined frequency band by a filter, for example, and then transmitted to the antenna and transmitted to the outside from the antenna. The antenna is an antenna of a mobile phone, for example.

  The sub line 5 is electromagnetically connected to the main line 4. A part of a signal transmitted through the main line is transmitted to the sub line by using an electromagnetic connection between the main line 4 and the sub line 5. The signal transmitted to the sub line 5 is transmitted to an IC or the like electrically connected to the sub line 5 for processing, and the signal level transmitted through the main line 4 is monitored. That is, the signal level transmitted through the main line 4 is sent to the IC for comparing the signal level via the sub line 5. In this IC, for example, when the input signal level is lower than the set signal level, feedback is performed to increase the output level to the power amplifier, and vice versa when the signal level is high. In this case, the circuit included in the IC is relatively low at about 20Ω as described above. Therefore, the connection part with the low impedance circuit among the sublines 5 is set to a relatively low impedance.

  The main line 4 and the sub line 5 are formed of, for example, a metal material such as copper, silver, palladium, platinum, tungsten, molybdenum, or manganese, or an alloy metal material containing these metal materials, like the ground conductor layer 3. ing. These metal materials are provided in the predetermined part of the laminated body 1 in the form of a metallized layer or a plating layer.

  If the main line 4 and the sub line 5 are made of, for example, a copper metallized layer, a metal paste prepared by kneading copper powder together with an organic solvent and a binder is used as a predetermined ceramic green sheet for the laminate 1. It can be formed by printing on a site by a method such as screen printing and baking.

  In the high frequency module 10 of the embodiment, the end of the sub line 5 opposite to the end connected to the IC is connected to the termination resistor. Termination processing is performed on the signal transmitted through the sub line 5 by the termination resistor. For example, the resistance value of the termination resistor is set to the same resistance value as that of the IC.

  The termination resistor may be an independent circuit component such as a ceramic chip resistor component, or may be a resistor circuit (printed circuit or the like) formed on the substrate on which the directional coupler 9 is mounted. Good.

  The distance between the main line 4 and the ground conductor layer 3 of the directional coupler 9 and the distance between the sub line 5 and the ground conductor layer 3 are the impedance value of the circuit to which the sub line 5 is connected, the insulating layer In accordance with conditions such as the material 2 (relative dielectric constant), the material forming the sub-line 5 and the width of the sub-line, the impedance is appropriately set to have a predetermined impedance value.

For example, the main line 4 and the sub line 5 are made of a copper metallized layer, the insulating layer 2 is made of a glass ceramic sintered body (relative permittivity: 8.0) mainly composed of borosilicate glass and aluminum oxide, and the main line 4 If the line width of the sub line 5 is 75 μm, the distance between the main line 4 and the ground conductor layer 3 is set to about 340 to 360 μm. The distance between the sub line 5 and the ground conductor layer 3 is set to about 40 to 60 μm. As a result, the impedance of the main line 4 becomes about 50Ω, and the impedance of the sub line becomes about 20Ω.

  FIG. 3 is an exploded perspective view showing a modification of the directional coupler shown in FIG. In the example of FIG. 3, the distance between the sub line 5 and the ground conductor layer 3 is smaller than the distance between the main line 4 and the ground conductor layer 3 over the entire length of the sub line 5. Further, both ends of the main line 4 and the sub line 5 are electrically led to the first main surface and the second main surface of the multilayer body 1 through via conductors, respectively.

  Since the impedance of the sub-line 5 is kept relatively low over the entire length of the sub-line 5, it is more advantageous in matching impedance between the sub-line 5 and a low-impedance circuit such as an IC.

  The via conductor is a through conductor that penetrates one or a plurality of insulating layers 2 in the thickness direction. In FIG. 3, via conductors are schematically shown using broken lines. For example, the via conductor is provided with a through hole in a ceramic green sheet to be the insulating layer 2 and is filled with the same metal paste as that for forming the ground conductor layer 3 in the through hole, and simultaneously fired with the ceramic green sheet. Can be provided. The through hole can be formed by a punching process such as a mechanical punching process using a metal pin or a process using a laser beam. When filling the through hole with the metal paste, means such as vacuum suction are used together to facilitate filling of the metal paste.

  Portions of the via conductor that are electrically led to the first main surface and the second main surface constitute the connection terminal 7 of the directional coupler 9. The connection terminal 7 may be composed of, for example, only the end portion of the via conductor, or may be composed of this end portion and a cover conductor (not shown) such as a metallized layer covering the end portion. Further, the exposed surface may be coated with a plating layer such as nickel and gold.

  The ground conductor layer 3 provided on substantially the entire surface of each of the first and second main surfaces of the multilayer body 1 is not formed in the portion where the end portion of the via conductor is located. Thereby, the possibility that the via conductor and the ground conductor layer 3 are electrically short-circuited with each other is reduced.

  Further, the connection terminal 7 is connected to a predetermined portion of a connection circuit included in a substrate on which the directional coupler 9 is mounted via a conductive connection material such as solder. Electrically connected to circuit components (resistor components, ICs, etc.) mounted on the board through the circuit for connecting the board such as the printed circuit board to which the connection terminal 7 of the directional coupler 9 is connected. Is done.

  The electrical connection between the main line 4 and the sub line 5 and the circuit for connecting the substrate does not necessarily have to be made via the connection terminal 7, and the end of the main line 4 or the sub line is laminated. It may be exposed to the outer surface of the body 1 and the circuit component may be directly connected to the exposed portion.

  About the directional coupler 9 of the said embodiment and its modification, it is located between the ground conductor layer 3 provided in the 2nd main surface among the some insulating layers 2, and the subline 5 in the low impedance connection part. However, the dielectric constant may be larger than the dielectric constant of the one located between the ground conductor layer 3 provided on the first main surface and the main line 4. In this case, the electrostatic capacitance generated between the sub line 5 and the ground conductor layer 3 is effectively increased by the interposition of the insulating layer 2 having a relatively high dielectric constant. Therefore, the directional coupler 9 that makes it easier to keep the impedance of the sub line 5 relatively low can be obtained.

  When the dielectric constant of the insulating layer 3 between the sub line 5 and the ground conductor layer 3 is larger than the dielectric constant of the insulating layer 3 between the main line 4 and the ground conductor layer 3, the sub line 5 and the ground conductor The insulating layer 3 between the layers 3 is formed of an insulating material having a relatively large dielectric constant. For example, if all of the plurality of insulating layers 2 are made of a glass ceramic sintered body, a glass component (ratio) such as borosilicate glass included in the insulating layer 2 between the sub line 5 and the ground conductor layer 3. What is necessary is just to make the content rate of a dielectric constant about 4-6 smaller than the content rate of the glass component contained in the insulating layer 2 between the main line 4 and the insulating layer 3. FIG. In other words, for example, the insulating layer 2 for which the dielectric constant is desired to be increased is set so as to include more components such as aluminum oxide having a relatively high dielectric constant (relative dielectric constant is about 8).

  Even in this case, it is not necessary that the dielectric constant of all the insulating layers 2 between the sub-line 5 and the ground conductor layer 3 is relatively large, depending on a desired capacitance value (impedance value). The dielectric constant of only some of the insulating layers 2 may be increased.

  Note that the directional coupler and the high-frequency module of the present invention are not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention. For example, the directional coupler 9 may be one (not shown) in which a plurality of main lines and sub-lines are paired with each other (upward and downward facing each other) and provided as a single laminate.

  Moreover, about the main line 4 and a subline, either one width | variety may be wider than the other width | variety. In this case, the possibility of a shift between the main line 4 and the sub line 5 due to a stacking shift of the insulating layer 2 or the like is reduced.

  Moreover, the thickness of the some insulating layer 2 does not need to be the same mutually, and the thing from which thickness differs may be contained. In this case, the distance between each of the main line 4 and the sub line 5 and the ground conductor layer 3 can be adjusted not only by the number of layers of the insulating layer 2 but also by the thickness of the insulating layer 2. it can.

DESCRIPTION OF SYMBOLS 1 ... Laminated body 2 ... Insulating layer 3 ... Grounding conductor layer 4 ... Main line 5 ... Sub line 6 ... Line part 7 ... Connection terminal 9. Directional coupler
10 ... High frequency module

Claims (3)

A stacked body including a plurality of insulating layers stacked on each other and having a first main surface and a second main surface facing each other;
A pair of ground conductor layers provided on the first main surface and the second main surface of the multilayer body and facing each other across the multilayer body;
A main line and a sub-line that are provided in order from the first main surface side in the multilayer body between the pair of ground conductor layers and face each other with a part of the plurality of insulating layers interposed therebetween The main line is electrically connected to a circuit having a first impedance value, and
The sub-line includes a low-impedance connection portion that is electrically connected to a low-impedance circuit having a second impedance value lower than the first impedance value. the distance between the contact Keru said second main surface to the ground conductor layer provided between the sub-line, than the distance between the first major surface to the ground conductor layer provided between the main line Is a small directional coupler. In the low impedance connection portion, a dielectric constant of the plurality of insulating layers located between the ground conductor layer provided on the second main surface and the sub line is in the first main surface. The directional coupler according to claim 1, wherein the directional coupler is larger than a dielectric constant of what is located between the ground conductor layer provided and the main line. The directional coupler according to claim 1 or 2,
A high-frequency module comprising: a circuit in which the coupler is electrically connected.

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