JP2016100344A - High-frequency coil device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-frequency coil device that can suppress great increase of a conductor loss even when the wire width of a conductor pattern is reduced, and also suppress reduction of self-inductance and mutual-inductance caused by increasing the thickness of the overall conductor pattern.SOLUTION: A high-frequency coil device has a laminate 10 having plural laminated base material layers, a conductor pattern disposed along the base material layer, and an interlayer connection conductor that is formed on the base material layer and conducted to the conductor pattern. The conductor pattern contains linear conductor patterns 21 to 24, and a coil having a winding axis in the lamination direction of the plural base material layers is constructed by the linear conductor patterns and the interlayer connection conductors. The linear conductor patterns 21 to 24 are formed by conductive paste patterns printed on the base material layers. The thickness of the inner portion 20M of a coil opening of the coil based on the conductive paste pattern is larger than the thickness of an outer portion 20E of the coil opening of the coil based on the conductive paste pattern.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a high-frequency coil device such as an inductor, a transformer, and a high-frequency circuit including a high-frequency coil.

  Patent Document 1 discloses a power feeding element using a transformer. This element is a power supply element with a wide band and low loss, and is useful as a power supply element for a multiband main antenna.

  In the transformer structure element, a coil is formed in a laminated body in which a plurality of base material layers are laminated. The coil includes a conductor pattern disposed along the base material layer and an interlayer connection conductor formed on the base material layer and conducting to the conductor pattern. The conductor pattern includes a linear conductor pattern, and a coil having a winding axis (center axis) in the stacking direction of the plurality of base material layers is configured by the linear conductor pattern and the interlayer connection conductor.

International Publication No. 2011/090080

  With downsizing of electronic devices such as mobile phone terminals, there is an increasing demand for downsizing of high-frequency coil devices such as inductors, transformers, and high-frequency circuits provided with high-frequency coils. As shown in Patent Document 1 and the like, in a high-frequency coil device created by a sheet laminating method, it is necessary to reduce the line width of a coil conductor pattern as the size is reduced. However, by reducing the line width of the conductor pattern, the current density per unit volume at the edge in the line width direction increases, so the conductor loss increases.

  On the other hand, the inventors have found that the following problems become conspicuous by reducing the line width of the conductor pattern.

  FIG. 13A is a cross-sectional view taken along a plane orthogonal to the extending direction of the conductor pattern when the conductive paste pattern 21P is printed on the base material layer 15. FIG. FIG. 13B is a cross-sectional view in a state where the base material layer 15 on which the conductive paste pattern 21P is printed is laminated together with a plurality of base material layers. As shown in FIG. 13A, when the conductive paste pattern 21P is printed on the base material layer 15, a pattern with the conductive paste pattern 21P having a constant thickness is formed. Thereafter, when the base material layer 15 on which the conductive paste pattern 21P is printed is laminated together with a plurality of base material layers, as shown in FIG. spread. Thus, as the line width of the conductor pattern becomes thinner, the edge in the line width direction of the conductor pattern becomes rounder, and the cross-sectional shape in the plane orthogonal to the extending direction becomes closer to an ellipse. In particular, the portion closer to the end of the line width extends in the surface direction. As a result, the cross-sectional shape becomes close to an ellipse. That is, the conductor pattern has a shape in which no edge stands at the edge in the line width direction. In the high frequency region, the current concentrates on the surface of the conductor pattern due to the skin effect, so that the current density at the edge portion in the line width direction increases due to the cross-sectional shape, and a large conductor loss occurs in this portion.

  FIG. 14A is a conceptual diagram of the coil, and FIG. 14B is a cross-sectional view of the AA portion in FIG. As shown in FIGS. 14A and 14B, the current density in the inner portion of the coil opening of the conductor pattern is further increased due to the influence of the magnetic flux φ passing through the opening of the coil. Since this high current density portion has a tapered shape, the conductor loss becomes more prominent.

  Therefore, when the coil is used for a filter or the like, for example, the insertion loss is deteriorated.

  On the other hand, if the electrode thickness is increased by simply applying the conductive paste twice or increasing the printing thickness (emulsion thickness) in order to reduce the conductor loss, the dimensions in the stacking direction of the coil forming region will increase. Thus, the obtained inductance becomes small. Further, when a transformer is configured, the coupling coefficient between the primary coil and the secondary coil becomes small, and not only the self-inductance but also the mutual inductance becomes small. As a result, the Q value (= ωL / R) of the coil is deteriorated.

  An object of the present invention is to provide a high-frequency coil device that suppresses a significant increase in conductor loss even if the line width of the conductor pattern is reduced, and to increase the overall thickness of the conductor pattern, An object of the present invention is to provide a high-frequency coil device that suppresses a decrease in mutual inductance.

(1) The high-frequency coil device of the present invention is formed on a laminate in which a plurality of base material layers are laminated, a conductor pattern arranged along the base material layer, and the base material layer. A conductive interlayer connection conductor. The conductor pattern includes a linear conductor pattern, and the linear conductor pattern and the interlayer connection conductor constitute a coil having a winding axis (center axis) in the stacking direction of the plurality of base material layers. The linear conductor pattern is formed by a conductive paste pattern printed on the base material layer, and a thickness of an inner portion of the coil opening of the coil by the conductive paste pattern is determined by the conductive paste pattern. It is thicker than the thickness of the outer part of the coil opening of the coil.

  With the above configuration, the thickness of the conductor pattern in the portion where the current density tends to increase is secured, current concentration is relaxed, and the conductor loss is reduced. In addition, compared with the case where the entire thickness of the conductor pattern is increased, the range of the coil formation region in the stacking direction of the base material layer does not increase, so that the wire length and the number of turns required to obtain a predetermined inductance can be reduced. This increases the Q value (= ωL / R) of the coil.

(2) The linear conductive pattern includes a second conductive paste pattern having a line width corresponding to a line width of the linear conductive pattern, and a first conductive paste pattern narrower than a line width of the second conductive paste pattern. The first conductive paste pattern is printed on an inner portion of the coil opening on the base material layer, and the second conductive paste pattern is formed on the base material layer and the first conductive property. It is preferably printed on the paste pattern. With this configuration, the roundness of the edge in the line width direction of the conductor pattern is reduced, the thickness and volume of the conductor pattern in the portion with a high current density are ensured, and the conductor loss is more effectively reduced.

(3) It is preferable that the linear conductor patterns formed on the plurality of base material layers overlap in the stacking direction of the plurality of base material layers. With this configuration, the magnetic coupling between the layers of the conductor pattern is increased, and the line length and the number of turns required to obtain a predetermined inductance can be reduced, thereby increasing the Q value of the coil.

(4) Moreover, the high frequency coil apparatus of this invention is formed in the laminated body by which the several base material layer was laminated | stacked, the conductor pattern arrange | positioned along the said base material layer, and the said base material layer, The said conductor An interlayer connection conductor conducting to the pattern. The conductor pattern includes a linear conductor pattern, and each of the first coil and the first coil has a winding axis (center axis) in the stacking direction of the plurality of base material layers by the linear conductor pattern and the interlayer connection conductor. 2 coils are formed, and the linear conductor pattern is formed by a conductive paste pattern printed on the base material layer, and the thickness of the inner part of the coil opening of the coil by the conductive paste pattern It is thicker than the thickness of the outer part of the coil opening of the coil by the conductive paste pattern.

  With the above configuration, the thickness of the conductor pattern in the portion where the current density tends to increase is secured, current concentration is relaxed, and the conductor loss is reduced. In addition, since the range of the coil formation region in the direction of lamination of the base material layer does not become larger than when the overall thickness of the conductor pattern is increased, the line length and the number of turns required to obtain a predetermined inductance and mutual inductance The Q value of the first coil and the second coil is increased.

(5) In the above (4), for example, the first coil and the second coil are coupled via a magnetic field to constitute a transformer.

  According to the present invention, the thickness of the portion of the conductor pattern that tends to increase the current density is secured, the current concentration is relaxed, and the conductor loss is reduced. In addition, compared with the case where the entire thickness of the conductor pattern is increased, the range of the coil formation region in the stacking direction of the base material layer does not increase, so that the wire length and the number of turns required to obtain a predetermined inductance can be reduced. As a result, a high-frequency coil device having a high Q value can be obtained. Further, if the Q values are equal, a smaller high-frequency coil device can be configured.

FIG. 1 is an external perspective view of the impedance conversion circuit according to the first embodiment. FIG. 2 is an internal perspective view of the impedance conversion circuit 101. FIG. 3 is a diagram showing conductor patterns and current paths formed on each base material layer of the impedance conversion circuit 101. FIG. 4 is a cross-sectional view of the impedance conversion circuit 101 obtained by laminating and pressing each of the base material layers shown in FIG. FIG. 5A is a cross-sectional view in a plane orthogonal to the extending direction of the conductive paste pattern when the conductive paste patterns 21P1 and 21P2 are printed on the base material layer 15. FIG. FIG. 5B is a cross-sectional view in a state where the base material layer 15 on which the conductive paste patterns 21P1 and 21P2 are printed is laminated together with a plurality of base material layers, and these are pressure-bonded and fired. FIGS. 6A and 6B are comparative examples with respect to FIGS. FIG. 7A is a circuit diagram of the impedance conversion circuit 101 shown in FIGS. 2 and 3, and FIG. 7B is an equivalent circuit diagram of the impedance conversion circuit 101. FIGS. 8A and 8B are cross-sectional views taken along a plane orthogonal to the extending direction of the extending direction of the conductive paste pattern after the conductive paste is printed twice on the base material layer. FIG. 9 is a cross-sectional view of the impedance conversion circuit 102 according to the second embodiment. FIG. 10 is a cross-sectional view of another impedance conversion circuit 102A according to the second embodiment. FIG. 11A is a circuit diagram in which the circuit illustrated in FIG. 7A is simplified and includes a resistance component. FIG. 11B is a diagram showing the circuit of FIG. 11A as an equivalent circuit including an ideal transformer. FIG. 12 is an exploded perspective view of the impedance conversion circuit 103 as an example of the high-frequency coil device according to the third embodiment. FIG. 13A is a cross-sectional view taken along a plane orthogonal to the extending direction of the conductor pattern when the conductive paste pattern 21P is printed on the base material layer 15. FIG. FIG. 13B is a cross-sectional view in a state where the base material layer 15 on which the conductive paste pattern 21P is printed is laminated together with a plurality of base material layers. FIG. 14A is a conceptual diagram of the coil, and FIG. 14B is a cross-sectional view of the AA portion in FIG.

  Hereinafter, several specific examples will be given with reference to the drawings to show a plurality of modes for carrying out the present invention. In the drawings, the same reference numerals are given to the same portions. In the second and subsequent embodiments, description of matters common to the first embodiment is omitted, and different points will be described. In particular, the same operation effect by the same configuration will not be sequentially described for each embodiment.

<< First Embodiment >>
In the first embodiment, an impedance conversion circuit is shown as an example of a high-frequency coil device.

  FIG. 1 is an external perspective view of the impedance conversion circuit according to the first embodiment. The impedance conversion circuit 101 includes a stacked body 10 configured by stacking a plurality of insulator base layers. In this laminate 10, a plurality of coils constituted by a conductor pattern and an interlayer connection conductor are provided.

  FIG. 2 is an internal perspective view of the impedance conversion circuit 101. However, the dimensions in the stacking direction are exaggerated in consideration of the easy understanding of the stacked structure. The actual dimensions are, for example, 1.6 × 0.8 mm on the mounting surface and 0.6 mm in height.

  As shown in FIG. 2, four coil conductors LP 1, LP 2, LP 3, LP 4 are formed in the laminated body 10. The coil conductors LP1, LP2, LP3, LP4 are interlayer-connected by vias (interlayer connection conductors) V11, V12, V21, V22, etc. at predetermined positions.

  On the outer surface of the laminated body 10, external terminals, that is, a power feeding terminal P1, an antenna terminal P2, a ground terminal P3, and an empty terminal NC are formed. Specifically, the power supply terminal P1 is formed on the first side surface of the laminated body 10, and the antenna terminal P2 is formed on the second side surface facing the first side surface. A ground terminal P3 is formed on the third side surface, and an empty terminal NC is formed on the fourth side surface facing the third side surface. On the lower surface and the upper surface of the laminated body 10, a feeding terminal P1, an antenna terminal P2, a ground terminal P3, and an empty terminal NC connected to the external terminals on the side surfaces are formed, respectively.

  FIG. 3 is a diagram showing conductor patterns and current paths formed on each base material layer of the impedance conversion circuit 101. A first coil conductor LP1 is formed on the base material layer 15, a second coil conductor LP2 is formed on the base material layer 14, a third coil conductor LP3 is formed on the base material layer 13, and a fourth coil conductor LP4 is formed on the base material layer 12. . These base material layers 11 to 15 are dielectric (insulator) or magnetic layers. For example, the laminate 10 may be configured by using dielectric ceramic green sheets, stacked and pressure-bonded, and fired. Alternatively, the laminate 10 may be configured by pressing a resin sheet. Alternatively, the laminated body 10 may be formed by using green sheets of magnetic ceramics, laminating and pressing them, and firing them. Alternatively, the laminated body 10 may be formed by pressing a resin sheet in which a magnetic filler is dispersed. It may be configured. Furthermore, only the layer to be the magnetic core may be a magnetic material, and the other layers may be a dielectric material.

  The first coil conductor LP1 and the second coil conductor LP2 constitute a first coil element L1. The first coil conductor LP1 is composed of conductor patterns L1A and L1B1. The end of the conductor pattern L1A is electrically connected to the power supply terminal P1. The second coil conductor LP2 is composed of conductor patterns L1C and L1B2. The first coil conductor LP1 and the second coil conductor LP2 are partially connected in parallel via the vias V11 and V12 so as to form a partially cut-out loop shape, and the whole is connected in series.

  The third coil conductor LP3 and the fourth coil conductor LP4 constitute a second coil element L2. The third coil conductor LP3 is composed of conductor patterns L2B2 and L2C. The end of the conductor pattern L2C is electrically connected to the antenna terminal P2. The fourth coil conductor LP4 is composed of conductor patterns L2A and L2B1. The end of the conductor pattern L2A is electrically connected to the ground terminal P3. The third coil conductor LP3 and the fourth coil conductor LP4 are partially connected in parallel via the vias V22 and V23 and are connected in series so as to form a partially notched loop shape.

  FIG. 4 is a cross-sectional view of the impedance conversion circuit 101 obtained by laminating and pressing each of the base material layers shown in FIG. This cross-sectional position corresponds to the AA portion in FIG. The linear conductor patterns 21, 22, 23, and 24 in FIG. 4 correspond to the coil conductors LP1, LP2, LP3, and LP4 shown in FIG. In these linear conductor patterns 21, 22, 23, and 24, the average thickness of the coil inner portion (near the coil opening) 20M is larger than the average thickness of the coil outer portion (near the coil opening) 20E. Also thick. In this example, from the center of the line width of the linear conductor pattern, the inside of the coil opening is shown as an inward portion, and the outside is shown as an outward portion.

  The linear conductor patterns 21, 22, 23, and 24 include a thick portion 20H having a large thickness and a thin portion 20L having a small thickness. The thick part 20H is near the coil inner part 20M, and the thin part 20L is near the coil outer part 20E.

  Thus, the thickness of the linear conductor patterns 21 to 24 tends to be thicker inside than the outside of the coil. For example, the average thickness of the thick part 20H is 10 μm, and the average thickness of the thin part 20L is 3 μm. Although the boundary between the thick portion 20H and the thin portion 20L of the linear conductor pattern may not be clear (arbitrary), the thick portion 20H is usually inward from the center of the line width of the linear conductor pattern. .

  FIG. 5A is a cross-sectional view in a plane orthogonal to the extending direction of the conductive paste pattern when the conductive paste patterns 21P1 and 21P2 are printed on the base material layer 15. FIG. FIG. 5B is a cross-sectional view in a state where the base material layer 15 on which the conductive paste patterns 21P1 and 21P2 are printed is laminated together with a plurality of base material layers, and these are pressure-bonded and fired.

  First, the first conductive paste pattern 21P1 is printed on the base material layer 15. Thereafter, the second conductive paste pattern 21P2 having a line width corresponding to the line width 20W of the linear conductor pattern 21 is printed. The line width 20WP1 of the first conductive paste pattern 21P1 is narrower than the line width 20WP2 of the second conductive paste pattern 21P2.

  The first conductive paste pattern 21P1 is printed on the inner side of the coil opening on the base material layer 15, and the second conductive paste pattern 21P2 is printed on the base material layer 15 and the first conductive paste pattern 21P1. .

  With this configuration, as shown in FIG. 5B, the roundness of the edge E of the coil inner portion 20M of the linear conductor pattern 21 is reduced. Thus, the thickness and volume of the conductor pattern of the coil inner portion 20M having a high current density are ensured, and the conductor loss is more effectively reduced.

  FIGS. 6A and 6B are comparative examples with respect to FIGS. This comparative example is also included in the present invention. In the case of the comparative example, first, a second conductive paste pattern having a line width corresponding to the line width 20 W of the linear conductor pattern 21 is printed on the base material layer 15. Thereafter, the first conductive paste pattern 21P1 is printed. The line width 20WP1 of the first conductive paste pattern 21P1 is narrower than the line width 20WP2 of the second conductive paste pattern 21P2.

  Since the conductive paste pattern has a greater spread as the line width increases, as shown in FIG. 6A, the second conductive paste pattern 21P2 is printed by printing the second conductive paste pattern 21P2 (first printing). Oozes relatively greatly in the line width direction. On the other hand, in the printing of the first conductive paste pattern 21P1 (second printing), since the first conductive paste pattern 21P1 has a small line width, the first conductive paste pattern 21P1 has little bleeding. Therefore, as shown in FIG. 6B, the edge E of the coil inner portion 20M of the linear conductor pattern 21 is rounded (the cross-sectional shape becomes a tapered shape). For this reason, the effect of reducing the current density of the coil inner portion 20M is small. However, since the thickness of the coil inner portion 20M of the linear conductor pattern 21 is thicker than that of the coil outer portion 20E, current concentration is alleviated. That is, there is an effect of reducing the conductor loss.

  In FIG. 3, a current flows through the first coil conductor LP1 and the second coil conductor LP2 through a path of the power supply terminal P1, the conductor pattern L1A, the conductor pattern (L1B1 + L1B2), the conductor pattern L1C, and the antenna terminal P2. In addition, a current flows through the third coil conductor LP3 and the fourth coil conductor LP4 through a path of the antenna terminal P2, the conductor pattern L2C, the conductor pattern (L2B2 + L2B1), the conductor pattern L2A, and the ground terminal P3.

  FIG. 7A is a circuit diagram of the impedance conversion circuit 101 shown in FIGS. 2 and 3, and FIG. 7B is an equivalent circuit diagram of the impedance conversion circuit 101. The power feeding circuit 30 is connected to the power feeding terminal P1 of the impedance conversion circuit 101, and the antenna 40 is connected to the antenna terminal P2. The ground terminal P3 is connected to the ground.

  The impedance conversion circuit 101 includes a first coil element L1 connected to the power supply terminal P1 and a second coil element L2 coupled to the first coil element L1. More specifically, the first end of the first coil element L1 is connected to the feeding terminal P1, the second end is connected to the antenna terminal P2, and the first end of the second coil element L2 is connected to the antenna terminal P2. The second ends are connected to the ground terminal P3.

  The impedance conversion circuit 101 includes a transformer type circuit in which the first coil element L1 and the second coil element L2 are tightly coupled via mutual inductance. That is, it is a high-frequency transformer device in which the first coil element L1 and the second coil element L2 are coupled via a magnetic field. As shown in FIG. 7B, this transformer type circuit can be equivalently converted into a T type circuit including three inductance elements Z1, Z2, and Z3. That is, this T-type circuit has a power supply terminal P1 connected to the power supply circuit 30, an antenna terminal P2, a ground terminal P3, an inductance element Z1 connected between the power supply terminal P1 and the branch point A, and a branch with the antenna terminal P2. An inductance element Z2 connected between the point A and a third inductance element Z3 connected between the ground terminal P3 and the branch point A is configured.

<< Second Embodiment >>
In 2nd Embodiment, the magnitude relationship of the thickness of the linear conductor pattern in a coil inner part and a coil outer part shows the example which is not one way.

  FIGS. 8A and 8B are cross-sectional views taken along a plane orthogonal to the extending direction of the extending direction of the conductive paste pattern after the conductive paste is printed twice on the base material layer. FIG. 9 is a cross-sectional view of the impedance conversion circuit 102 according to the second embodiment.

  FIG. 8A shows an example in which the first conductive paste pattern 21P1 is printed on the outer portion of the coil, as shown in the first embodiment. In FIG. 8B, the first conductive paste pattern 22P1 is printed on the inner part of the coil, and then the second conductive paste pattern 22P2 having a line width corresponding to the line width 20W of the linear conductor pattern 22 is printed. It is an example.

  9, the linear conductor patterns 23 and 24 are formed by the conductive paste pattern shown in FIG. 8A, and the linear conductor patterns 21 and 22 are shown in FIG. 8B. It is formed by a conductive paste pattern.

  Thus, by including both the linear conductor patterns 21 and 22 where the coil inner part is thick and the linear conductor patterns 23 and 24 where the coil outer part is thick, the stress due to the lamination of the base material layers is relieved, and the lamination The flatness of the upper and lower surfaces of the body 10 is increased.

  FIG. 10 is a cross-sectional view of another impedance conversion circuit 102A according to the second embodiment. In FIG. 10, the linear conductor patterns 22 and 24 are formed by the conductive paste pattern shown in FIG. 8A, and the linear conductor patterns 21 and 23 are shown in FIG. 8B. It is formed by a conductive paste pattern.

  As described above, the linear conductor patterns 21 and 23 having thick inner portions of the coil and the linear conductor patterns 22 and 24 having thick outer portions of the coil are alternately laminated so that the interlayer distance t of the linear conductor patterns is constant. It becomes. Therefore, it becomes easy to narrow the distance between the layers of the linear conductor pattern as a whole, thereby increasing the coupling coefficient between the coils. Moreover, the stress by lamination | stacking of a base material layer is relieve | moderated more, and the flatness of the upper and lower surfaces of the laminated body 10 improves more.

  In both the example shown in FIG. 9 and the example shown in FIG. 10, the coil having a thick linear conductor pattern is contrary to the purpose of reducing the conductor loss. If there is a coil to further reduce the coil, a pattern that can reduce the conductor loss for that coil (pattern in which the outer part of the coil opening of the linear conductor pattern becomes thick) is used, and for the other coils, the linear conductor What is necessary is just to make it the pattern which the inner part of the coil opening of a pattern becomes thick.

  Here, the impedance conversion circuit having the circuit configuration shown in FIG. 7 in the first embodiment is taken as an example to illustrate a coil that preferentially reduces conductor loss.

  FIG. 11A is a circuit diagram in which the circuit illustrated in FIG. 7A is simplified and includes a resistance component. FIG. 11B is a diagram showing the circuit of FIG. 11A as an equivalent circuit including an ideal transformer. Here, the coupling coefficient between the first coil element L1 and the second coil element L2 is k, the mutual inductance due to the coupling is M, the Q value of the first coil element L1 is Q1, and the Q value of the second coil element L2 is Q2. The values of the circuit constants shown in FIG. 11B are as follows.

M = k√ (L1 ・ L2)
Rs = (R1 · L2 + R2 · L1) / (L1 + L2 + 2M)
= ΩL1 · L2 {(1 / Q1) + (1 / Q2)} / (L1 + L2 + 2M)
Rp = R1 + R2
= ΩL1 / Q1 + ωL2 / Q2
In other words, Rs is effective at a constant rate regardless of which Q value of the first coil element L1 or the second coil element L2 is improved. On the other hand, with regard to Rp, improving the Q value of the larger one of the first coil element L1 and the second coil element L2 reduces Rp, and the effect of improving the insertion loss is greater.

  Accordingly, in the arrangement of the coil conductors having the structure shown in FIG. 3 in the first embodiment, when the inductance value of the second coil element L2 is larger than the inductance value of the first coil element L1, it is shown in FIG. If the structure is adopted, an impedance conversion circuit in which the laminate 10 has high flatness and improved insertion loss can be obtained.

<< Third Embodiment >>
In the third embodiment, a high-frequency coil device including a laminate having a characteristic structure is shown.

  FIG. 12 is an exploded perspective view of the impedance conversion circuit 103 as an example of the high-frequency coil device according to the third embodiment.

  The impedance conversion circuit 103 includes base material layers 11 to 16 as in the impedance conversion circuit 101 shown in FIGS. 2 and 3 in the first embodiment. The conductor pattern formed on the base material layer is not shown. In the present embodiment, external terminals are formed only on the lower surface of the base material layer 11. In the impedance conversion circuit 103 of the present embodiment, a magnetic base material layer 17 is further provided between the base material layer 11 and the base material layer 12, and a magnetic base material is provided between the base material layer 15 and the base material layer 16. Each is provided with a material layer 18. A via V made of a plurality of magnetic materials is formed between the base material layer 17 and the base material layer 18. The plurality of coil conductors are surrounded by magnetic base layers 17 and 18 and vias made of a magnetic material.

  With this structure, the magnetic flux generated by the first coil element L1 and the second coil element L2 can be confined. Moreover, since the distance between the external ground conductor facing the side surface of the impedance conversion circuit 103 and the magnetic member can be separated compared to a structure in which the side surface of the laminate is coated with a magnetic material, for example, the vortex generated in the external ground conductor The current can be further reduced. Further, since the magnetic flux contributing to the characteristics is confined in the vicinity of the first coil element L1 and the second coil element L2, the spread of the magnetic flux is small and a high inductance is obtained. Further, the coupling coefficient between the first coil element L1 and the second coil element L2 is increased. Furthermore, eddy currents generated in the ground conductor formed on the printed wiring board can be reduced in a state where the impedance conversion circuit 103 is mounted on the printed wiring board, thereby improving the inductance value and the coupling coefficient.

  Further, by arranging the magnetic base material layer 17 in a layer close to the mounting surface (the lower surface of the base material layer 11), eddy currents generated in the mounting terminals and the like are suppressed. As a result, characteristic deterioration can be suppressed.

  In each of the embodiments described above, an example has been described in which each coil conductor has a substantially rectangular loop shape, but the loop shape of the coil conductor is not limited thereto. For example, it may be a circle, an ellipse, a quadrangle with rounded corners, a quadrangle with rounded corners, or the like. If it is a rectangle, a coil opening can be earned in a limited space. If it is a circle, an ellipse, or a quadrangle with rounded corners, the loss at the corners can be reduced.

  Finally, the description of the above embodiment is illustrative in all respects and not restrictive. Modifications and changes can be made as appropriate by those skilled in the art. For example, partial replacements or combinations of the configurations shown in the different embodiments are possible. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

E ... edge L1 ... first coil element L2 ... second coil element L1A, L1B1, L1B2, L1C ... conductor pattern L2A, L2B1, L2B2, L2C ... conductor pattern LP1 ... first coil conductor LP2 ... second coil conductor LP3 ... second 3 coil conductor LP4 ... 4th coil conductor P1 ... feeding terminal P2 ... antenna terminal P3 ... ground terminals V, V11, V12, V22, V23 ... vias Z1, Z2, Z3 ... inductance element 10 ... laminates 11-18 ... substrate Layer 20E ... outer part 20M of coil opening ... inner part 20H of coil opening ... thick part 20L ... thin part 21,22,23,24 ... linear conductor pattern 21P ... conductive paste pattern 21P1,22P1 ... first conductivity Conductive paste patterns 21P2, 22P2 ... second conductive paste patterns 21-24 ... linear conductor pattern 30 ... power feeding Road 40 ... antenna 101,102,102A, 103 ... impedance conversion circuit

Claims (5)

A laminate in which a plurality of base material layers are laminated;
A conductor pattern disposed along the base material layer;
An interlayer connection conductor formed on the base material layer and conducting to the conductor pattern;
With
The conductor pattern includes a linear conductor pattern,
A coil having a winding axis in the stacking direction of the plurality of base material layers is constituted by the linear conductor pattern and the interlayer connection conductor,
The linear conductor pattern is formed by a conductive paste pattern printed on the base material layer, and the thickness of the inner part of the coil opening of the coil by the conductive paste pattern is the coil by the conductive paste pattern. Thicker than the thickness of the outer part of the coil opening,
A high-frequency coil device characterized by that. The linear conductor pattern includes a second conductive paste pattern having a line width corresponding to the line width of the linear conductor pattern, and a first conductive paste pattern thinner than the line width of the second conductive paste pattern. Prepared,
The first conductive paste pattern is printed on an inner portion of the coil opening on the base material layer, and the second conductive paste pattern is printed on the base material layer and the first conductive paste pattern. The high frequency coil device according to claim 1, wherein   3. The high-frequency coil device according to claim 1, wherein the linear conductor patterns formed on the plurality of base material layers overlap each other when viewed in a stacking direction of the plurality of base material layers. A laminate in which a plurality of base material layers are laminated;
A conductor pattern disposed along the base material layer;
An interlayer connection conductor formed on the base material layer and conducting to the conductor pattern;
With
The conductor pattern includes a linear conductor pattern,
A first coil and a second coil each having a winding axis in the stacking direction of the plurality of base material layers are constituted by the linear conductor pattern and the interlayer connection conductor,
The linear conductor pattern is formed by a conductive paste pattern printed on the base material layer, and the thickness of the inner part of the coil opening of the coil by the conductive paste pattern is the coil by the conductive paste pattern. Thicker than the thickness of the outer part of the coil opening,
A high-frequency coil device characterized by that.   The high frequency coil device according to claim 4, wherein the first coil and the second coil are coupled via a magnetic field to constitute a transformer.

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