JP6315347B2 - Directional coupler and module using the same - Google Patents

Description

  The present invention relates to a directional coupler formed by laminating a plurality of insulator layers on which a conductor pattern is formed and configured using a transmission line formed by the conductor pattern, and a module using the directional coupler.

  In recent years, wireless communication devices such as mobile phones have rapidly spread, and directional couplers are required to be miniaturized with excellent electrical characteristics, reflecting the trend of miniaturization, thinning, and weight reduction. In a laminated directional coupler, which will be described later, for 800 MHz band, downsizing is progressing to an outer dimension of about 1.0 mm × 0.5 mm × 0.4 mm.

  FIG. 11 shows an example of an equivalent circuit of a directional coupler. FIG. 11A shows an equivalent circuit represented as a distributed constant circuit. The directional coupler is used to distribute a signal flowing in one transmission line (main line) to the other transmission line (sub line). Both ends of each transmission line SL1, SL2 are terminated with a predetermined characteristic impedance Zo. The operating frequency is usually determined by the length of the transmission lines SL1 and SL2, and is determined according to the shortening of the wavelength according to the dielectric constant and permeability of the medium (insulator) that supports the transmission lines SL1 and SL2. Therefore, the effective length is set to a length of ¼λ (λ; wavelength).

  The equivalent circuit of such a directional coupler can also be expressed as a lumped constant circuit. The inductances of the transmission line SL1 and the transmission line SL2 shown in FIG. 11A are coils L1 and L2, respectively, and the capacitance between the transmission line SL1 and the transmission line SL2 is a capacitor Cs. If the electrostatic capacity between the ground and the ground is replaced with a capacitor Cg1, and the electrostatic capacity between the transmission line SL2 and the ground is replaced with a capacitor Cg2, the equivalent circuit of FIG. 11B is obtained.

  12A is a plan view showing a configuration example of a general directional coupler, and FIG. 12B is an A-A ′ sectional view thereof. In the directional coupler shown in FIG. 12, the transmission path is configured with a microstrip structure. This is a symmetrical four-terminal circuit including terminals P1 to P4, which is configured by two transmission lines 101 and 102, which are arranged in parallel with each other on the insulator 110 and in parallel with the ground plane 103.

  When the transmission line 101 is a main line SL1 through which a high-frequency signal passes and the transmission line 102 is a sub-line SL2 that distributes a part of the high-frequency signal, the electric field coupling and magnetic field coupling between the main line SL1 and the sub-line SL2 The high frequency signal input to the main line SL1 is propagated to the sub line SL2. When the terminal P1 of the transmission line 101 is an input terminal for a high frequency signal, the terminal P2 is an output terminal. The terminal P3 of the transmission line 102 becomes a coupling terminal that outputs a high-frequency signal corresponding to the coupling between the main line SL1 and the sub-line SL2, and the high-frequency signal appears with a phase shift of 90 ° from the terminal P2. The terminal P4 is an isolation terminal, and the phase of the high frequency signal appearing at the terminal P4 is further shifted by 90 °. If the transmission line is viewed as an ideal differential transmission line, the phase appearing at the terminal P4 becomes a high-frequency signal whose phase is shifted by 180 °, and cancels out with the high-frequency signal appearing at the terminal P2. Therefore, ideally, the high-frequency signal appears at P4. Absent.

The characteristics of such a directional coupler are explained by an even-mode characteristic impedance Z1e and an odd-mode characteristic impedance Z1o. If the transmission lines 101 and 102 are provided on a homogeneous medium, the characteristic impedance of each mode is expressed by the following equation.
Z1e = (ε × μ) ^1/2 / Cg (1)
Z1o = (ε × μ) ^1/2 / (Cg + Cs) (2)
ε: dielectric constant of medium μ: magnetic permeability Cg of medium: capacitance between transmission paths 101 and 102 and ground plane 103 Cs: capacitance between transmission path 101 and transmission path 102

If the transmission lines 101 and 102 are provided in the homogeneous medium 110, the electrical length in the even mode and the electrical length in the odd mode are equal, and the termination impedance Zo is Zo = (Z1e × Z1o) ^1/2 From the impedance matching condition at each terminal, the degree of coupling K between the transmission path 101 and the transmission path 102 is expressed by the following equation.
K = −20 × log ₁₀ {(Z1e−Z1o) / (Z1e + Z1o)} (dB) (3)

From Equations (1) to (3), the degree of bonding K is expressed by the following equation using Cg and Cs.
K = −20 × log ₁₀ {Cs / (Cg + Cs)} (dB) (4)

  From Equation (4), if a large degree of coupling K is to be obtained, the electrostatic capacitance Cg between the transmission lines 101 and 102 and the ground plane 103 is reduced, and the electrostatic capacitance between the transmission line 101 and the transmission line 102 is reduced. It can be seen that the capacitance Cs should be increased.

Further, the reflection coefficient S11, the attenuation coefficient S21, the coupling coefficient S31, and the isolation coefficient S41, which are scattering matrix parameters (S parameters) representing the high-frequency characteristics of the directional coupler, are the even-mode reflection coefficient S11e, attenuation The coefficient S21e, the odd-mode reflection coefficient S11o, and the attenuation coefficient S21o are expressed by the following equations.
S11 = (S11e + S11o) / 2 (5)
S21 = (S21e + S21o) / 2 (6)
S31 = (S11e−S11o) / 2 (7)
S41 = (S21e−S21o) / 2 (8)

The directionality D of the directional coupler is expressed by the following equation using S parameters from equations (7) and (8).
D = 20 × log ₁₀ (| S31 |) −20 × log ₁₀ (| S41 |) (dB) (9)

  It can be seen from Equation (9) that a large directivity D can be obtained by increasing the coupling coefficient S31 and decreasing the isolation coefficient S41.

  The directional coupler shown in FIG. 12 has a configuration in which transmission lines are arranged on one side and face each other, and is called an edge coupling type. In addition, a directional coupler having a broadside coupling structure configured by overlapping transmission lines is also widely used. Similar to the edge-coupled directional coupler, the above description can be applied to the directional coupler having the broadside-coupled structure in terms of the matching conditions and the degree of coupling.

  FIG. 13 is an external perspective view of a directional coupler having a broadside coupling structure disclosed in Patent Document 1. FIG. FIG. 14 is an exploded perspective view showing the internal structure. The directional coupler 400 has a transmission path configured in a laminated body. A transmission line conductor 432 and a transmission line conductor 431 formed of a conductor pattern are arranged in the laminated body with an interval in the lamination direction. A terminal electrode 450 connected to each transmission line conductor is provided on the side surface. Such stacked directional couplers have less electrical field leakage and better electrical characteristics than edge-coupled directional couplers, and are advantageous for miniaturization. Has been widely used.

  This directional coupler 400 is produced by laminating and firing ceramic green sheets provided with a conductor pattern. The plurality of laminated ceramic green sheets are integrated after firing. In FIG. 14, the directional coupler 400 that is an integral structure is shown in an exploded manner for the sake of convenience into insulator layers 411 to 415 corresponding to ceramic green sheets provided with a conductor pattern.

  The insulator layer 412 is formed with a U-shaped transmission line conductor 431 that constitutes the transmission line (sub line) SL2, and a lead conductor 433 that connects both ends to the terminal electrode 450 on the side surface. The insulator layer 413 is formed with a U-shaped transmission line conductor 432 that constitutes the transmission line (main line) SL1 with a conductor pattern, and an extraction conductor 434 that connects both ends to the terminal electrode 450 on the side surface. The transmission line conductor 431 and the transmission line conductor 432 overlap and are electromagnetically coupled via the insulator layer 413. Furthermore, the insulator layers 411 and 414 on which the ground conductors 421 and 422 made of a conductor pattern are formed are laminated at a predetermined interval with the transmission path conductor 431 and the transmission path conductor 432 interposed therebetween. With such a configuration, the transmission path is shielded so that noise from the outside enters the directional coupler and is superimposed on a high-frequency signal, or noise is not leaked from the directional coupler 400 to the outside. Further, an insulator layer 415 covering the ground conductor 422 is overlaid on the insulator layer 414.

  Further downsizing is also required for the directional coupler having a broadside coupling structure. In considering the reduction in size and height of a directional coupler, the problem is how to form a conductor pattern while obtaining desired electrical characteristics in a limited space. If the distance between the transmission line and the ground conductor is simply narrowed in an attempt to reduce the height of the directional coupler, the capacitance increases, the characteristic impedance decreases, and the difference from the termination impedance increases. Inconsistency will be invited.

  The characteristic impedance can be adjusted by selecting the dielectric constant and permeability of the medium (insulator) that supports the transmission line conductor constituting the transmission line, the distance between the transmission line conductor constituting the transmission line and the ground plane, or This is done by adjusting the width of the transmission line conductors that make up the transmission line. However, there are only a limited number of industrially available media, and it is difficult to simply increase the distance between the transmission line conductor and the ground plane in a limited space. In general, a decrease in characteristic impedance is suppressed by narrowing the width of the transmission line conductor.

  However, several problems become apparent due to the narrowing of the transmission line conductor. First, the narrower the width of the transmission line conductor, the more difficult it is to form. Further, the transmission loss tends to increase as the wire becomes thinner, and depending on the power of the high-frequency signal passing therethrough, there is a concern that the transmission line conductor may be broken, and there is a problem in terms of power resistance. For this reason, there is a limit to the thinning of the transmission line conductor from the viewpoint of manufacturing, quality, and electrical characteristics, and in a small directional coupler, the characteristic impedance must be configured to be lower than the termination impedance. There was a case.

  Such mismatching of impedance causes an increase in reflection coefficient S11 and attenuation coefficient S21, resulting in a problem that the loss of high-frequency signals increases, and isolation is increased if the characteristic impedance of the transmission line is lower than the termination impedance. Thus, there is a problem that the directionality D deteriorates.

  It is known that the increase in isolation is caused by phase imbalance caused by the phase in the even mode operation being advanced earlier than the phase in the odd mode operation. In the even mode operation, the electric field concentration on the medium is smaller than in the odd mode, the apparent dielectric constant in the even mode appears to be smaller than the apparent dielectric constant in the odd mode, and the even mode phase is odd. In some cases, the phase difference may occur ahead of the phase of the mode. Such a phase difference causes a difference between the even-mode attenuation coefficient S21e and the odd-mode attenuation coefficient S21o, and the isolation coefficient S41 increases and the directionality D deteriorates.

  In addition, a similar problem that the directionality D deteriorates may occur due to a reactance component parasitic on the transmission path.

  In contrast to such degradation of directionality D due to impedance mismatch, the directional coupler of Patent Document 2 reduces the difference from the phase during odd mode operation by delaying the phase during even mode operation. Propose to improve the direction.

  FIG. 15 is an exploded perspective view showing the internal structure of the directional coupler disclosed in Patent Document 2. As shown in FIG. This directional coupler is also composed of a laminated body including insulator layers 551, 552, 553, 554, 555 and conductor patterns 501, 502, 511, 512. The transmission line conductors 501 and 502 are configured by a conductor pattern facing in the stacking direction via the insulator layer 553, and the ground conductor 511 is formed by a conductor pattern arranged with the transmission path conductors 501 and 502 sandwiched in the stacking direction. 512 is configured. Each of the ground conductors 511 and 512 is provided with deletion portions 521 and 522 from which the conductor is removed.

  The deleted portions 521 and 522 of the ground conductors 521 and 522 are openings arranged immediately below the coupling portions of the transmission line conductors 501 and 502, and the dimensions thereof are sufficiently large for ¼λ of the operating frequency. For example, it is 1 / 10λ or less. During even mode operation, the current that flows in the ground conductors 521 and 522 flows so as to bypass the opening, and the phase is delayed compared to the case where there is no opening to bring the even mode phase and the odd mode phase closer to improve isolation. It is said that the deterioration of directionality can be suppressed.

JP-A-5-152814 JP 2014-192690 A

  In the directional coupler of Patent Document 2, the distance between the transmission line conductor and an electric wall described later is determined to be closer than the distance between the transmission line conductor and the ground conductor, so that transmission is performed in odd mode operation. It is described that the lines of electric force generated from the path conductor exist only between the transmission path conductor and the electric wall, and the phase of the odd mode is not affected by the opening. Here, it is assumed that a plane parallel to the transmission path conductors 501 and 502, which is in the middle of the overlapping direction of the transmission path conductors 501 and 502, is an electrical wall that is a complete conductor.

  However, as described above, in the directional coupler having a small size and a low profile, the transmission line conductor must be disposed close to the ground conductor in a limited space. FIG. 16 is a diagram for explaining the electric field distribution in the directional coupler having the deletion portion in the ground conductor. The smaller the directional coupler is, the more difficult it is to have a configuration in which an electric field distribution does not occur between the transmission line conductor and the ground conductor during the odd mode operation. For this reason, the phase changes even during the odd mode operation, and both the even mode phase and the odd mode phase change. Therefore, trial and error are required to reduce the phase difference.

  In addition, since the electric field is distributed to the outside of the ground conductor from the deletion portions 521 and 522 of the ground conductors 511 and 512, it may be difficult to confine in the medium. May leak outside or enter inside.

  In addition, the coupling portion of the transmission line conductors 501 and 502 includes a region overlapping the ground conductors 511 and 512 and a region overlapping the deletion units 521 and 522, and the characteristic impedance in each region is discontinuously different. It is a step impedance line. The characteristic impedance of the transmission line conductors 501 and 502 is greatly affected by the area overlapping with the deletion units 521 and 522. That is, adjusting the deletion units 521 and 522 so as to suppress the phase difference between the even mode and the odd mode leads to fluctuations in characteristic impedance, while considering the characteristic impedance of the transmission line conductors 501 and 502. It is considerably difficult to improve the isolation by suppressing the phase difference.

As described above, a small and low-profile directional coupler is required to improve the reduction in characteristic impedance. It is also desired that the directionality can be improved by suppressing an increase in isolation due to mismatch with the termination impedance.
Therefore, in the present invention, the matching with the termination impedance is improved, the size of the microstrip line can be suppressed while preventing the increase in transmission loss by reducing the size of the microstrip line, and the directionality can be suppressed by improving the isolation. An object is to provide a sex coupler and a module using the same.

  The present invention has a laminated structure in which a plurality of insulator layers are laminated, and transmission lines composed of transmission line conductors extending in a plane perpendicular to the lamination direction are arranged in the lamination direction via the insulator layers. A directional coupler comprising opposing transmission line forming parts and a ground conductor extending in a plane orthogonal to the stacking direction and sandwiching the transmission line forming part, wherein the ground conductors are insulator layers Are connected via via holes provided in the first conductor, and at least one of them is a first conductor having a small distance from the transmission line conductor in the stacking direction and the same side as the first conductor, and the distance is large. A second conductor, wherein the first conductor and the second conductor are connected via a via hole provided in an insulator layer, and the first conductor overlaps with the transmission line in a stacking direction. No conductor is provided, and the second conductor is A directional coupler, characterized in that the ground conductor structure overlapping the first conductor to cover the region of the part.

  In the directional coupler according to the present invention, it is preferable that the second conductor is provided on a surface on one side in the stacking direction of the multilayer body. Furthermore, it is preferable that the surface includes a ground terminal connected to the first conductor together with the second conductor, and a signal terminal connected to the transmission path.

  In the directional coupler according to the present invention, it is preferable that the transmission line on the surface side is a main line and the other transmission line is a sub line. Further, it is preferable that one transmission line has a longer overall length than the other transmission line and is configured in a coil shape. Further, the transmission line formed in the coil shape is used as a main line, and the transmission line constitutes one end side thereof. It is more preferable that the path conductor and the transmission path conductor constituting the transmission path serving as the sub line are opposed to each other.

  In the directional coupler according to the present invention, it is preferable that both of the ground conductors are constituted by the ground conductor structure including a first conductor and a second conductor.

  The module using the directional coupler according to the present invention includes at least two transmission paths opposed to each other in the stacking direction via an insulating layer, and at least the first of the ground conductors facing the two transmission paths. It is preferable to use a common conductor.

  According to the present invention, the matching with the termination impedance is improved, the microstrip line is thinned to prevent the transmission loss from being increased while the size is small, the coupling degree and the isolation are improved, and the deterioration of the directivity is suppressed. A directional coupler that can be provided can be provided. In addition, by providing a plurality of directional couplers of the present invention in a laminate, a module can be further reduced in size.

It is an external appearance perspective view of the directional coupler which concerns on one Example of this invention. It is a disassembled perspective view which shows the example of an internal structure of the directional coupler shown in FIG. It is XZ sectional drawing which cut | disconnected the directional coupler shown in FIG. 1 in the center part of the Y direction. It is a figure for demonstrating the electric field distribution of the directional coupler which concerns on one Example of this invention. It is a figure for demonstrating the example of a shape of the opening part formed in the 1st conductor of the ground conductor of a directional coupler. It is a disassembled perspective view which shows the internal structure of the directional coupler which concerns on the other Example of this invention. It is a figure which shows the equivalent circuit of the directional coupler shown in FIG. (A) It is an external appearance perspective view of the modularized directional coupler, (b) It is a figure for demonstrating the circuit arrangement | positioning inside. It is a disassembled perspective view which shows the internal structure of the directional coupler shown in FIG. It is a figure for demonstrating the structure of the front end part of the mobile telephone comprised using the directional coupler shown in FIG. (A) It is a figure which shows the equivalent circuit of a general directional coupler with a distributed constant circuit, (b) It is a figure which shows the equivalent circuit of a general directional coupler with a lumped constant circuit. (A) It is a top view which shows the structure of the conventional directional coupler, (b) It is a figure which shows the A-A 'cross section. It is an external appearance perspective view of another conventional directional coupler. It is a disassembled perspective view for demonstrating the internal structure of the directional coupler shown in FIG. It is a disassembled perspective view for demonstrating the internal structure of another conventional directional coupler. It is a figure for demonstrating the electric field distribution state at the time of the even mode operation | movement of the directional coupler shown in FIG.

Hereinafter, embodiments will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is an external perspective view of a directional coupler according to an embodiment of the present invention, FIG. 2 is a perspective view for explaining the internal structure, and FIG. 3 is an XZ sectional view thereof. The directional coupler 10 is configured by laminating a plurality of conductor patterns (transmission path conductors, ground conductors) 11, 12, 21, 22, 25, 26 and insulator layers S1 to S6. One of the main surfaces of the directional coupler 10 facing the stacking direction is provided with a conductor pattern 22 that is a part of a ground conductor and terminal electrodes (ground terminal 50, signal terminals 31 to 34). Yes. In the drawings, the configuration of the invention is appropriately omitted and emphasized for easy understanding. The equivalent circuit of the directional coupler has the same configuration as the general equivalent circuit shown in FIG.

  The transmission line conductor 11 constituting the main line SL1 and the transmission line conductor 12 constituting the sub line SL2 are opposed to each other in the stacking direction (Z direction in the figure) so as to be coupled via the insulator layer S3. Be placed. Each of the transmission line conductors 11 and 12 has a strip line structure sandwiched between ground conductors 21 and 22 disposed on the lower side and ground conductors 25 and 26 disposed on the upper side. The ground conductors 21, 22, 25, and 26 are connected through a plurality of via holes GH provided in the insulator layer. Note that “upper and lower” represents a relative position in the Z direction, and is used to facilitate explanation of the structure. It goes without saying that the essence of the invention does not change even if the words are upside down.

  The ground conductor structure used in the directional coupler of the present invention will be described in more detail using the ground conductor located below the transmission line conductor 11. The ground conductor is composed of two conductors provided at different positions in the stacking direction. The two conductors are relatively large in distance between the first conductor 21 having a small distance from the transmission line conductor 11 in the stacking direction and the transmission line conductor 11 on the same side as the first conductor 21. This is the second conductor 22. Although not shown in FIG. 3, as can be seen from FIG. 2, the first conductor 21 and the second conductor 22 are connected via via holes GH provided at both ends in the Y direction of the insulator layer S1. Yes.

  The first conductor 21 is provided with an opening 17 (no conductor is formed) in a region overlapping the transmission line conductor 11 in the stacking direction. The second conductor 22 overlaps with the opening 17 in the stacking direction to cover the region, and is disposed so as to overlap the first conductor 21. Further, the first conductor 21 is connected to the ground terminal 50 among the terminal electrodes provided on the same main surface as the second conductor 22 via the via hole GH. According to such a configuration, since the gap between the ground conductor and the transmission line conductor can be widened, it is possible to suppress a decrease in the characteristic impedance of the transmission line.

  Further, by forming the second conductor 22 of the ground conductor together with the terminal electrode on one surface of the directional coupler, an increase in the insulating layer necessary for providing the second conductor 22 can be suppressed. Then, the bonding strength of the directional coupler can be improved by using the second conductor 22 together with the terminal electrode by soldering to the circuit board.

  Similarly, the ground conductor located above the transmission line conductor 12 is also composed of two conductors (first conductor 25 and second conductor 26) provided at different positions in the stacking direction. An opening 17 similar to the first conductor 21 is provided in the first conductor 25 having a small distance from the transmission line conductor 12 in the stacking direction. The second conductor 26, which is relatively larger than the first conductor 25 with respect to the transmission line conductor 12, is formed to be slightly larger than the second conductor 22, and has four via holes GH provided in the insulator layer S5. Is connected to the first conductor 25. Similarly, via holes GH are provided in the insulator layers S2 to S4, and the via holes GH are connected to each other so that the ground conductors positioned above and below are connected to the transmission line conductors 11 and 12, respectively. Since the transmission line conductors 11 and 12 are shielded from the ground conductors 21, 22, 25, and 26, the directional coupler does not impair noise resistance.

  The transmission line conductor 11 provided in the insulator layer S2 and the transmission line conductor 12 provided in the insulator layer S3 are located at the center in the X direction and extend linearly in the Y direction, respectively. Both end sides extend in the X direction and are formed in an alphabetic U shape. In the transmission line conductors 11 and 12, portions extending linearly in the Y direction are opposed to each other via the insulator layer S3 to form a coupling portion.

  Both ends of the transmission line conductor 11 and via terminals HL provided in the insulator layers S1 and S2 are connected to signal terminals 33 and 34 among terminal electrodes formed on the lower main surface. Both ends of the transmission line conductor 12 are connected to signal terminals 31 and 32 of the terminal electrodes formed on the lower main surface via via holes HL provided in the insulator layers S1 to S3. The outer periphery of the first conductor 21 is formed to be recessed so as not to interfere with the via hole HL. In place of the via holes GH and HL, the signal electrodes 31 to 34 may be connected by side electrodes like the conventional directional coupler shown in FIG.

  In the ground conductor structure used in the directional coupler of the present invention, at least a part of the transmission line conductor 11 is opposed to the second conductor 22 through the opening 17 provided in the first conductor 21 of the ground conductor. Let Similarly, at least a part of the transmission line conductor 12 is opposed to the second conductor 26 through the opening 17 provided in the first conductor 25 of the ground conductor.

  FIG. 4 shows the electric field distribution during the even mode operation and the odd mode operation of the directional coupler configured with such a ground conductor structure. In the figure, electric lines of force are schematically indicated by arrows, but their positions, numbers, etc. do not quantitatively indicate the distribution.

  Electric fields are generated between the transmission path conductor 11 and the second conductor 22 and between the transmission path conductor 12 and the second conductor 26 through the opening 17 that overlaps the coupling portion of the transmission path conductors 11 and 12. According to such a configuration, the characteristic impedance of the region overlapping with the opening 17 can be made higher than that of other portions, and a decrease in the characteristic impedance of the transmission line can be suppressed.

  An increase in transmission loss can be suppressed by reducing the characteristic impedance of the transmission line to the termination impedance Zo without reducing the width of the transmission line conductors 11 and 12. Further, by improving the impedance matching, the phase difference between the even mode and the odd mode is reduced, so that the isolation can be improved and the deterioration of the directivity can be suppressed. Furthermore, since the capacitance Cg between the transmission line and the ground conductor can be reduced without reducing the capacitance Cs between the transmission lines, the degree of coupling K is improved, and the deterioration of directionality is further suppressed. I can do it.

  In addition, the grounding conductor facing one transmission line is composed of two conductors provided at different positions in the laminating direction, and these are electrically connected via via holes and further opposed to the other transmission line. The ground electrode to be connected is also connected with a via hole. With such a ground conductor structure, current flows through the via hole between the connected ground conductors, so even a small, low-profile directional coupler can affect the phase of odd-mode operation. While suppressing the phase of the even mode operation, the phase difference between the even mode and the odd mode can be reduced to improve the isolation, and the deterioration of the directionality can be suppressed.

  In the present invention, only the ground conductor facing one transmission line may be composed of two conductors.

  In the example illustrated above, the opening 17 provided in the first conductors 21 and 25 is rectangular, but other shapes may be used. Another configuration example of the opening provided in the first conductor is shown in FIG. FIG. 5A shows an example in which the opening 17 is configured as a slit in which the conductor is removed in the longitudinal direction (Y direction) of the directional coupler. In this case, the characteristic impedance and the phase difference of the transmission line can be adjusted by changing the width of the opening 17.

  In FIG. 5B, the widths of the openings 17 are formed discontinuously, and the wide regions W1 and the narrow regions W2 are alternately provided. FIG. 5C shows a plurality of openings 17. FIG. 5D shows a configuration in which the end of the opening 17 in the longitudinal direction is gradually narrowed. In FIGS. 5B to 5D, by forming the openings 17 discontinuously, in addition to the width of the openings 17, the characteristic impedance and the phase difference can be adjusted according to the length, number, and the like. I can do it.

  For the insulator layer that supports the conductor for the transmission line, dielectric ceramics, resin, a composite material of resin and ceramic, or the like can be used. The directional coupler of the present invention can be manufactured using known materials and construction methods, and is not limited with respect to the material of the conductor pattern and the insulator layer and the manufacturing method.

  For example, when using dielectric ceramics, LTCC (low-temperature co-fired ceramic) technology or HTCC (high-temperature co-fired ceramic) technology may be used, and it can also be produced by a build-up technology using a resin material or the like. .

  In the case of LTCC technology, a ceramic dielectric that can be sintered at a low temperature of 1000 ° C. or lower is used as the insulator layer. As a plurality of ceramic green sheets having a thickness of 10 to 200 μm, a conductive paste such as Ag or Cu is printed on the sheet to form a predetermined conductor pattern, which is laminated and integrally sintered. I can do it. As the ceramic dielectric, for example, ceramics containing Al, Si and Sr as main components and Ti, Bi, Cu, Mn, Na, K etc. as subcomponents, ceramics containing Al, Mg, Si and Gd, Al, Si , Zr, and Mg-containing ceramics.

(Embodiment 2)
FIG. 6 is an exploded perspective view for explaining another configuration of the directional coupler. FIG. 7A is an equivalent circuit in which the directional coupler of FIG. 6 is shown by a distributed constant circuit, and FIG. 7B is an equivalent circuit shown by a lumped constant circuit. The configuration of this directional coupler will be described below with a focus on different parts while omitting the description of the same parts as those of the directional coupler shown in the first embodiment.

  The first conductor 21 of the ground conductor provided on one surface of the insulator layer S1 is provided with an opening 17 having a shape that matches the transmission path described later. The second conductor 22 is formed on the other surface of the insulating layer S1 together with the terminal electrodes 31 to 34, and the first conductor 21 and the second conductor 22 are connected via the via hole GH.

  Insulator layers S2 to S4 are formed with transmission line conductors 11-1 to 11-3 of less than one turn, and coil-shaped transmission lines wound around three turns by connecting the end portions thereof via via holes HL. Is the main track. FIG. 6 is an example, and the number of windings is appropriately set to obtain a desired characteristic as a directional coupler, and is not limited to the illustrated number.

  In the insulator layer S5, the transmission line conductor 12 having less than one turn is formed, and is disposed to face the transmission line conductor 11-3 provided in the insulator layer S4 via the insulator layer S5. A transmission line constituted by the transmission line conductors 12 is a sub line. A ground conductor 26 is disposed on the insulator layer S6 disposed above the insulator layer S5. There is an insulator layer (not shown) between the insulator layer S5 and the insulator layer S6, and the distance between the ground conductor 26 and the transmission line conductor 12 is determined. An insulator layer (not shown) includes a via hole GH, but does not have a transmission line conductor or a ground conductor. Since the ground conductor 26 has the same form as the second conductor having no opening, the reference numeral assigned to the second conductor shown in FIG. 2 is given. The upper and lower ground conductors are electrically connected via a via hole GH. An insulator layer S7 that covers the ground conductor 26 is disposed on the insulator layer S6. Since the sub-line handles less power than the main line, it is easier than the main line to reduce the characteristic impedance by narrowing the width of the transmission line conductor, and as illustrated, it has an opening. In some cases, it may be possible to use a ground conductor that is not used.

  In a structure close to an ideal directional coupler using a linear transmission line as shown in FIG. 2, the opposing transmission line conductors are in the middle of the lamination direction between the ground conductors, Although there is an advantage that it is arranged symmetrically and is easy to design, on the other hand, since the transmission line is linear, it is also difficult to reduce the size. Therefore, in the directional coupler shown in FIG. 6, the transmission path is coiled. Since the self-inductance of the coiled transmission line is larger than that of the linear transmission line, the transmission line can be shortened and the directional coupler can be downsized. Each of the transmission paths may be coiled.

  In addition, when the functions of other circuits such as a matching circuit and a filter circuit are combined in a directional coupler, it is effective to use a coil as a means for increasing the self-inductance of the transmission line.

  In the structure shown in FIG. 6, the transmission line of the main line is formed in a coil shape so as to have a function different from that of the auxiliary line so that the directional coupler has a function of a matching circuit. A capacitor Cp shown in the equivalent circuit of FIG. 7B is formed by the parasitic capacitance distributed between the transmission line conductors 11-1 to 11-3 constituting the transmission line of the main line. Simply increasing the self-inductance of the transmission line of either the main line or the sub-line relatively tends to degrade the isolation characteristics, but in addition to adopting a ground conductor structure with an opening. By adjusting the capacitors Cs, Cg1, Cg2, and Cp according to the width and winding diameter of each transmission line conductor between the ground conductors or the arrangement in the stacking direction, the decrease in characteristic impedance is suppressed and the isolation is improved. Deterioration of directionality can be suppressed.

  In the illustrated example, the opening 17 of the first conductor 21 is configured by the first conductors 11-1 to 11-3, and the transmission line is viewed in the stacking direction, and substantially the entire conductor in the overlapping region is removed. . With such a configuration, the self-inductance of the transmission line can be further increased, and the quality factor Q can be increased.

(Embodiment 3)
FIG. 8A is an external perspective view of a modularized directional coupler, and FIG. 8B is a diagram for explaining an internal circuit arrangement. FIG. 9 is an exploded perspective view for explaining the internal structure. In this module, two low-pass filters are combined with two directional couplers inside the laminate.

  In the region divided into four when viewed in the stacking direction, directional couplers are provided in the regions A1 and A2, and low-pass filters are provided in the regions B1 and B2. A high-frequency switch, a reactance element that is not mounted on the stack, a resistance element, and the like are mounted on the top surface of the stack. The mounting component on the upper surface is protected by sealing with a resin or covering with a metal case.

  The equivalent circuit of the directional coupler formed in the module is the same as the circuit shown in FIG. The basic configuration is almost the same as the embodiment already described, but the ground conductor formed in the insulator layer S1 and the insulator layer S10 is common to the two directional couplers and the two low-pass filters. Is different. Of the ground conductors facing the two sets of transmission lines constituting the directional coupler, the first conductor is common.

  The ground conductors formed in the insulator layer S1 and the insulator layer S10 are connected by a plurality of via holes. The directional coupler and the low-pass filter are partitioned by the via hole groups arranged in parallel, and further, the directional coupler is partitioned. The via hole is filled with a metal conductor and shields between circuits to reduce electromagnetic interference. The metal conductor of the via hole is preferably in a tightly packed state, but may have a hollow portion as long as the electrical connection and the shielding function are not hindered.

  The layer configuration will be described in order from the lower side in the stacking direction. The first conductor 21 of the ground conductor provided on one surface of the insulator layer S1 is provided with openings 17a and 17b having a shape corresponding to the transmission path located in the upper layer. Four second conductors 22a and 22b are provided on the other surface of the insulator layer S1 corresponding to the lower surface of the multilayer body and cover the lower portions of the openings 17a and 17b. The second conductor is electrically connected through a via hole (indicated by a black circle in the figure). A transmission line conductor constituting a coil of a low-pass filter described later is formed above the opening 17b.

  Insulator layers S2 to S4 are formed with transmission line conductors 11-1 to 11-3 constituting main lines of the directional coupler, and insulator layers S3 to S5 are transmissions constituting inductors of low-pass filters. A road conductor is formed. The insulator layer S6 is formed with a transmission line conductor 12 constituting a sub line of the directional coupler, and the insulator layers S6 to S9 are formed with conductors constituting a low-pass filter capacitor.

  The ground conductor 26 provided in the insulator layer S10 surrounds a via hole provided for connecting a directional coupler or a low-pass filter located under the ground conductor 26 to a component mounted on the upper surface of the multilayer body. Has a region where the conductor is removed. Connection lines are formed in the dielectric layers S11 and S12. In the uppermost dielectric layer S13, pads for mounting components are formed.

  FIG. 10 is a diagram for explaining a configuration example of the front end unit of the wireless communication apparatus. The module 2 including the directional coupler is disposed between the high frequency circuit including the amplifier and the antenna. One of the directional couplers CL1 and CL2 in the stack is connected to the low-pass filters F1 and F2, and the other is connected to the double-headed n-pole high-frequency switch ANT S / W mounted on the stack. One of the low-pass filters F1 and F2 is connected to the directional couplers CL1 and CL2, and the other is connected to the antennas ANT1 and ANT2. The high frequency switch ANT S / W is connected to a high frequency circuit including an amplifier, but may be connected via another circuit.

  A terminal electrode 60 is formed on the lower surface of the multilayer body so as to surround the second conductors 22a and 22b. The terminal electrode 60 includes a high-frequency signal terminal connected to the low-pass filters F1, F2, and the like, a ground terminal, a power signal terminal for operating the high-frequency switch ANT S / W, and the like. In this embodiment, the terminal electrode on the lower surface is LGA (Land Grid Array), but BGA (Ball Grid Array) or the like can also be adopted, and the terminal structure has a terminal electrode provided on the side surface of the laminate. Also good.

  With such a configuration, the directional coupler can suppress a decrease in characteristic impedance, improve isolation, and suppress deterioration in directivity. In addition, by using a module, a plurality of circuits can be integrated into a small size, and the high-frequency circuit in the front end portion of the wireless communication apparatus can be downsized. Moreover, the connection between circuits can be shortened and signal loss can be reduced.

2 Module 10 Directional coupler 11, 11-1, 11-2, 11-3 Transmission path conductor 12 Transmission path conductor 17 Openings 21, 21a, 21b, 22, 22a, 22b, 25, 26 Ground conductors HL, GH via holes S1 to S12 Insulator layers 31, 32, 33, 3450, 60 Terminal electrodes

Claims (9)

It has a laminate structure in which a plurality of insulator layers are laminated,
A main line which extend in a plane perpendicular to the stacking direction Ru consists of a transmission line conductor extends in a plane orthogonal to the stacking direction through an insulating layer provided on the main line composed of a transmission line conductor A transmission line forming section having a sub line ,
And the main line and the ground conductor via an insulator layer disposed on the sub-line extend in a plane perpendicular to the stacking direction is provided so as to sandwich the transmission path forming part of the transmission path forming section A directional coupler comprising:
The ground conductor to each other are connected via a via hole provided in the insulating layer,
Wherein said ground conductor provided on the main line side of the transmission line forming portion, opposite the first conductor spacing is small and the main line for the stacking direction, a surface of the main line side of the first conductor and A second conductor that is provided through an insulator layer disposed on the surface on the side to be connected and has a large distance from the main line ;
The first conductor and the second conductor are connected via a via hole provided in an insulator layer,
The first conductor is not provided with a conductor in a part of the region where the main line and the sub line overlap in the stacking direction, and the second conductor covers the part of the region and overlaps the first conductor. A directional coupler characterized by having a conductor structure. The directional coupler according to claim 1,
The directional coupler according to claim 1, wherein the second conductor is provided on a surface of the multilayer structure . A directional coupler according to claim 2,
On said surface, together with the second conductor, a directional coupler, characterized in that it comprises a ground terminal connected to the first conductor, the connection signal terminal and the transmission line conductor. The directional coupler according to any one of claims 1 to 3 ,
The directional coupler characterized in that the main line is longer in length than the sub line , and is configured in a coil shape. The directional coupler according to claim 4 , wherein
And the transmission path conductor constituting one end of the main line formed in a coil shape, a directional coupler, characterized in that said and said transmission line conductors that constitute the transmission line serving as a sub-line to face . A directional coupler according to any one of claims 1 to 5,
The directional coupler, wherein the second conductor on the main line side is provided at a position where an electric field is generated between the main line and the second conductor on the main line side. A directional coupler according to any one of claims 1 to 6, wherein said ground conductor of the sub-line side, a first conductor spacing is small between the sub-line to the stacking direction, the first It is provided through an insulator layer disposed on the surface on the side opposite to the surface on the sub-line side of one conductor, and is configured by the ground conductor structure including the second conductor having a large distance from the sub-line. A directional coupler characterized by that. A directional coupler according to claim 7,
The directional coupler, wherein the second conductor on the sub-line side is provided at a position where an electric field is generated between the sub-line and the second conductor on the sub-line side. A module using the directional coupler according to any one of claims 1 to 8 ,
The transmission path forming part of at least 2 Kumisonae, of opposing the ground conductor into two sets of the transmission path forming portion, the module being characterized in that a common at least a first conductor.

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