JP4358195B2 - ANTENNA DEVICE AND ANTENNA DEVICE MANUFACTURING METHOD - Google Patents

Description

  The present invention relates to an antenna device and a method for manufacturing the antenna device.

  In recent years, with the rapid increase in communication information, electronic communication devices have been reduced in size and weight. In connection with this, size reduction and weight reduction of an electronic component are desired. Current mobile communication terminals perform most of information propagation by transmitting and receiving radio waves. The frequency band of the radio wave used is a high frequency region of 100 MHz or more. For this reason, attention is paid to electronic components and substrates useful in this high frequency region. In portable mobile communication and sanitary communication, radio waves in the high frequency band of the gigahertz band are used.

  In order to cope with radio waves in such a high frequency range, it is necessary for the electronic parts to have low energy loss and transmission loss. For example, in an antenna device indispensable for a mobile communication terminal, a radio wave generated from the antenna causes a transmission loss in the transmission process. This transmission loss is consumed as heat energy in the electronic component and the board, and causes heat generation in the electronic component. Transmission loss cancels out radio waves to be transmitted to the outside. For this reason, it is necessary to transmit a strong radio wave, which hinders effective use of power. Furthermore, communication with as low a radio wave as possible is desired.

  With the increasing demand for such miniaturization and weight reduction, each electronic component is miniaturized to save space. However, it is indispensable for the antenna device to secure a distance from the electronic component and the substrate in order to suppress transmission loss for the reasons described above. For this reason, it is forced to have an unnecessary space, and it becomes difficult to save space.

  For this reason, an antenna device in which an antenna is formed on an insulating substrate (antenna substrate) made of a dielectric ceramic has been developed. This antenna device is small and saves space. However, since dielectric ceramic has dielectric loss, transmission loss becomes large. As a result, transmission / reception sensitivity cannot be obtained, and it is currently used as an auxiliary antenna, and there is a limit to power saving.

  An antenna device having a high-permeability insulating substrate as an antenna substrate can transmit and receive radio waves without reaching the electronic components and printed circuit boards in communication equipment because radio waves from the antenna can be wound around the antenna substrate. Is possible, that is, power saving is possible. A normal high magnetic permeability member is a metal or alloy containing Fe or Co as a component, or an oxide thereof. A metal or alloy high permeability member becomes difficult to use as an antenna substrate because transmission loss due to eddy current becomes significant when the frequency of radio waves increases. On the other hand, when an oxide magnetic material typified by ferrite is used as an antenna substrate, transmission loss due to eddy current is suppressed because of its high resistance, but since resonance frequency is several hundred MHz, transmission due to resonance at high frequencies. Loss becomes noticeable and difficult to use. For this reason, an insulating high magnetic permeability member that suppresses transmission loss as much as possible, which can be used for high-frequency radio waves, is required as a material for the antenna substrate.

  As an attempt to produce such a high magnetic permeability member, a high magnetic permeability nano-granular material is produced using thin film technology such as sputtering. However, this method requires a large facility, which is not practical in terms of cost and yield.

  Patent Document 1 discloses a high-permeability member made of a powder or a polycrystalline sintered body comprising a hardly-reducible metal oxide and metal particles made of at least one of Fe, Co, or an alloy thereof. Has been.

  However, the high magnetic permeability member disclosed in the above publication has an isotropic structure, a small shape magnetic anisotropy, and a relatively low resonance frequency. Therefore, the magnetic permeability decreases in the several gigahertz band.

Patent Document 2 includes a substrate, a metal oxide adhesive layer provided on the surface of the substrate, and an electromagnetic wave absorption laminate provided on the adhesive layer. A magnetic layer comprising a plurality of magnetic particles separated from each other by an electrically insulating material and having an average particle diameter of 1 to 150 nm, and (b) an electrical insulation layer, wherein the magnetic layer and the electrical insulation layer are at least two layers A printed wiring board is disclosed which is laminated in a multilayer structure having the following.
Japanese Patent Application Laid-Open No. 2004-281846 Publication No .: US 2004/0058138

  An object of this invention is to provide the antenna device provided with the antenna substrate which can perform highly efficient transmission / reception more stably, and its manufacturing method.

According to the present invention, an antenna substrate comprising a plurality of bonded insulator layers and a plurality of magnetic particles arranged so as to be buried in both of the insulator layers forming the interface at the bonding interface of these insulator layers ; And an antenna arranged directly on the main surface of the antenna substrate or in the vicinity of the main surface;
Equipped with a,
The plurality of insulator layers are oxides of at least one metal selected from Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf, and rare earth elements (including Y). And a ceramic layer containing an oxide of a magnetic metal, the composition is different between adjacent layers, and
An antenna device is provided in which the ceramic layer is included in the form of a complex oxide in which the metal and the magnetic metal are dissolved .
Further, according to the present invention, an antenna substrate comprising a plurality of bonded insulator layers and a plurality of magnetic particles disposed so as to be buried in both of the insulator layers forming the interface at the bond interface of these insulator layers ;and
An antenna disposed directly on or near the principal surface of the antenna substrate;
With
The arbitrary layer of the plurality of insulator layers is at least selected from Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf, and rare earth elements (including Y). A ceramic layer containing one metal oxide, the remaining layers being selected from Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf, and rare earth elements (including Y) A ceramic layer comprising at least one metal oxide and a magnetic metal oxide, and the composition is different between adjacent layers,
Among the insulator layers forming a bonding interface in which a plurality of the magnetic particles are arranged, at least one layer is a ceramic layer containing the metal oxide and the magnetic metal oxide, and
An antenna device is provided, wherein the ceramic layer including the metal oxide and the magnetic metal oxide is included in the form of a composite oxide in which the metal and the magnetic metal are dissolved.

According to the present invention, (a) at least one metal selected from the group consisting of Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf and rare earth elements (including Y) Forming the first and second ceramic green sheets containing the compound, having different compositions from each other, and containing at least one of the compound of the magnetic metal;
(B) a step of alternately laminating a plurality of the first and second ceramic green sheets;
(C) firing the ceramic green sheet laminate to produce a fired laminate in which a plurality of first and second ceramic layers are alternately laminated and bonded; and (d) reducing the fired laminate. An antenna device comprising: a step of precipitating the magnetic metal from a ceramic layer containing an oxide of a magnetic metal out of the first and second ceramic layers to an interface between the first and second ceramic layers. A manufacturing method is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the antenna device provided with the antenna substrate which can perform highly efficient transmission / reception more stably, and its manufacturing method can be provided.

  Hereinafter, an antenna device according to an embodiment of the present invention will be described in detail.

  An antenna device according to an embodiment includes an antenna substrate having a laminated body in which a plurality of magnetic particles are embedded in both of the insulating layers forming the interface at the bonding interface of the plurality of bonded insulating layers. ing. The antenna is arranged directly on the main surface of the antenna substrate or in the vicinity of the main surface. Here, “disposing the antenna in the vicinity of the main surface of the antenna substrate” means that an intermediate member such as an exterior resin layer or a spacer is disposed on the main surface of the antenna substrate, and the antenna is inserted into the antenna substrate via the intermediate member. Means to be placed on the main surface.

  The antenna substrate of such an antenna device has high magnetic permeability while suppressing transmission loss with respect to radio waves of 100 MHz to several GHz and high frequency transmitted or received by the antenna. As a result, since the radio wave transmitted or received by the antenna formed on the antenna substrate can be wound around the highly permeable antenna substrate, when the electronic circuit substrate is disposed with the antenna device in the communication device, It is possible to suppress or prevent radio waves from being absorbed by the electronic circuit board, and to perform highly efficient transmission / reception.

The insulator layer is preferably made of an insulating material having an insulation resistance of 1 × 10 ² Ω · cm or more at room temperature. As such an insulating material, for example, a ceramic such as an oxide or a nitride, an organic resin such as polystyrene, polyethylene, polyethylene terephthalate (PET), or an epoxy resin, or glass can be used.

  In particular, at least one of the plurality of insulator layers is selected from Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf, and rare earth elements (including Y). A ceramic layer containing an oxide of at least one metal (M1) is preferred. Further, at least one of the plurality of insulator layers is selected from Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf, and rare earth elements (including Y). A ceramic layer containing at least one metal (M1) oxide and magnetic metal (M2) oxide is preferred. The latter ceramic layer is allowed to contain 0.01 to 0.25% by atomic weight ratio of at least one additive metal (M3) selected from Al, Cr, Sc, Mn, B and Si. Note that a metal different from the metal (M1) is selected as the additive metal (M3).

  At least one of the plurality of insulator layers is allowed to be an organic resin layer. Examples of the organic resin layer include a form in which inorganic material particles are dispersed and contained, or a porous form in which cavities (bubbles) are dispersed and contained.

  The magnetic particles are preferably made of at least one magnetic metal selected from Fe, Ni, and Co, or an alloy containing these magnetic metals.

  The antenna is made of, for example, stainless steel, Ag, Ni, Cu, Au or the like.

  Next, the antenna device according to the embodiment will be specifically described with reference to the drawings.

  FIG. 1 is a plan view showing an antenna device according to the embodiment, FIG. 2 is a front view of FIG. 1, and FIG. 3 is an enlarged cross-sectional view of a main part of FIG.

  The antenna device 1 has a structure in which an antenna 30 is formed on an antenna substrate 10 as shown in FIGS.

  As shown in FIG. 3, the antenna substrate 10 includes first insulator layers 11 and second insulator layers 12 having compositions different from those of the first insulator layers, which are alternately stacked and joined, and the first and second layers. A plurality of magnetic particles 13 are disposed at the bonding interface between the first and second insulator layers 11 and 12 so as to be buried in both the first and second insulator layers 11 and 12. The plurality of magnetic particles 13 are buried in both the first and second insulator layers 11 and 12 that form the bonding interface.

  The first and second insulator layers 11 and 12 are selected from Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf, and rare earth elements (including Y). The ceramic layers include at least one metal (M1) oxide and have different compositions. In the ceramic layers used as the first and second insulator layers 11 and 12, at least one layer is allowed to contain an oxide of magnetic metal (M2).

  The stacked combinations of the first and second insulator layers 11 and 12 are specifically listed below.

  (1) First insulator layer 11; ceramic layer containing oxide of metal (M1), second insulator layer 12; oxide of metal (M1) different from oxide of first insulator layer 11 Including ceramic layer.

  (2) First insulator layer 11; ceramic layer including oxide of metal (M1), second insulator layer 12; including oxide of metal (M1) and oxide of magnetic metal (M2) Ceramic layer. In this embodiment, the metal (M1) oxide contained in the second insulator layer 12 is preferably different from the metal (M1) oxide contained in the first insulator layer 11.

  (3) First insulator layer 11; ceramic layer including oxide of metal (M1) and oxide of magnetic metal (M2); second insulator layer 12; including oxide of metal (M1) Ceramic layer. In this embodiment, the metal (M1) oxide contained in the second insulator layer 12 is preferably different from the metal (M1) oxide contained in the first insulator layer 11.

  (4) First insulator layer 11; ceramic layer containing oxide of metal (M1) and oxide of magnetic metal (M2); second insulator layer 12; A ceramic layer comprising an oxide of the metal (M1) different from an oxide of the metal (M1) and an oxide of the magnetic metal (M2).

  In the combination of (1) to (4), when the thermal expansion coefficient of the first insulator layer 11 is α1 and the thermal expansion coefficient of the second insulator layer 12 is α2, the temperature range is 80 ° C. to 1500 ° C. It is preferable that the condition of 0.5 <α1 / α2 <2 is satisfied.

In the combination of (1) to (4), it is preferable that the dielectric constant is different between the first and second insulator layers 11 and 12, that is, the dielectric constant is inclined. Specifically, the first insulator layer 11 in contact with the antenna 30 of the antenna substrate 10 is formed of a ceramic layer containing magnesia (MgO), and the second insulator layer 12 underneath is made of alumina (Al ₂ O ₃ ). A dielectric layer can be formed by including a ceramic layer. As described above, by providing a slope to the dielectric constant between the first and second insulator layers 11 and 12, it is possible to realize an antenna device having higher transmission / reception efficiency with respect to high-frequency radio waves of 100 MHz to several GHz.

In the combination of (2) to (4), the ceramic layer containing the oxide of the magnetic metal (M2) in addition to the oxide of the metal (M1) fixes the metal (M1) and the magnetic metal (M2). A dissolved complex oxide is preferred. Specifically, when MgO is used as the metal (M1) oxide and FeO is used as the magnetic metal (M2) oxide, the ceramic layer is preferably a Fe—Mg—O based composite oxide. When Al ₂ O _{3 is} used as the oxide of the metal (M1) and Fe ₂ O ₃ is used as the oxide of the magnetic metal (M2), the ceramic layer is a Fe—Al—O based composite oxide. It is preferable.

  In the combination of (2) to (4), at least one of the first and second insulator layers 11 and 12 from the ceramic layer containing the oxide of the magnetic metal (M2) in addition to the oxide of the metal (M1). By constituting one layer, an oxide of magnetic metal (M2) can be present between the plurality of magnetic particles 13 arranged at the bonding interface between the first and second insulator layers 11 and 12. Further, the magnetic coupling property between the magnetic particles 13 can be further improved. For this reason, even if the interval between the magnetic particles 13 is widened, it is possible to realize the antenna device 1 including the antenna substrate 10 exhibiting higher magnetic permeability with respect to high-frequency radio waves of 100 MHz to several GHz. .

  In the ceramic layer including the oxide of the metal (M1) and the oxide of the magnetic metal that is the metal (M2) in the combination of (2) to (4), at least one selected from Al, Cr, Sc, and Si One additive metal (M3) is allowed to be contained in an atomic weight ratio of 0.01 to 0.25%. Note that a metal different from the metal (M1) is selected as the additive metal (M3).

  The magnetic particles 13 are preferably made of at least one magnetic metal selected from Fe, Ni, and Co or an alloy containing these magnetic metals. Examples of the magnetic particles 13 include Fe particles, Co particles, Ni particles, Fe—Co particles, Fe—Ni particles, Co—Ni particles, and Fe—Co—Ni particles. The magnetic particles 13 may be alloyed with other nonmagnetic metals. However, if too much nonmagnetic metal is present, the saturation magnetization is too low. Therefore, in consideration of high-frequency characteristics, alloying with other nonmagnetic metals is preferably 10 atomic% or less. Furthermore, the nonmagnetic metal may be dispersed alone in the structure, but the amount is preferably 20% or less by volume ratio. In particular, from the viewpoint of saturation magnetization, the magnetic particles are preferably Fe—Co based particles. The magnetic particles 3 allow Al or Si as a second component to be dissolved in a proportion of 50% atom or less.

  The magnetic particles 13 preferably have a particle size of 1 to 100 nm. If the particle size of the magnetic particles 13 is less than 1 nm, superparamagnetism may occur and the saturation magnetic flux density may be reduced. On the other hand, when the particle size of the magnetic particles 13 exceeds 100 nm, eddy current loss occurs, and it becomes difficult to ensure the characteristics as the antenna substrate 10. On the other hand, when the particle diameter exceeds 100 nm, a multi-domain structure tends to be obtained due to energy stability. The high frequency characteristics of the magnetic permeability of the multi-domain structure may be lower than the high frequency characteristics of the magnetic permeability of the single magnetic domain structure. In particular, the upper limit particle diameter of the magnetic particles 13 is more preferably 50 nm from the viewpoint of maintaining a single magnetic domain structure. The most preferable particle diameter of the magnetic particles 13 is 10 to 50 nm.

  In the embodiment in which a plurality of magnetic particles 13 having a particle size in the above range are arranged at the bonding interface between the first and second insulator layers 11 and 12, the thickness of the first and second insulator layers 11 and 12 is as follows. It is desirable that the thickness be 0.05 to 100 μm, more preferably 0.05 to 1 μm, on the assumption that the magnetic particle is thicker than twice the particle size. The antenna substrate 10 having such thin first and second insulator layers 11 and 12 has higher magnetic permeability with respect to high-frequency radio waves of 100 MHz to several GHz due to the particle size of the magnetic particles 13. Have. In addition, the first and second insulator layers 11 and 12 having such a thickness are desirably stacked in a total of 100 layers or more, more preferably 500 to 2000 layers.

  In the embodiment in which a plurality of magnetic particles 13 having a particle size in the above range are arranged at the bonding interface between the first and second insulator layers 11 and 12, the distance between the magnetic particles 13 is preferably 10 nm or less. By arranging the plurality of magnetic particles 13 at the junction interface between the first and second insulator layers 11 and 12 at a distance of 10 nm or less, the magnetic coupling property between the magnetic particles 13 is improved, and 100 MHz to several GHz. It is possible to realize the antenna device 1 including the antenna substrate 10 having higher magnetic permeability with respect to high frequency radio waves. A more preferable distance between the magnetic particles 13 is 5 nm or less. However, when at least one of the first and second insulator layers 11 and 12 includes the oxide of the magnetic metal (M2), even if the distance between the magnetic particles 13 is about 10 nm, the magnetic force between the magnetic particles 13 is increased. Coupling properties can be sufficiently improved.

  The plurality of magnetic particles 13 have crystallinity such as single crystal or polycrystal, and the crystal orientation is a crystal of at least one insulator layer constituting particle of the first and second insulator layers 11 and 12. It is preferable to have a crystal orientation aligned with at least two axes with respect to the orientation. Such orientation (lattice matching) can be easily realized by forming the first and second insulator layers 11 and 12 with a ceramic layer containing an oxide of the metal (M1). It becomes possible. As described above, by providing a predetermined lattice matching between the plurality of magnetic particles 13 and at least one of the first and second insulator layers 11 and 12, the magnetic particles 13 are thermally treated. Thus, it can be made to exist at the interface between the first and second insulator layers 11 and 12 in a more stable state. As a result, the antenna device 1 including the antenna substrate 10 that can withstand long-time use can be realized.

  In the magnetic particles having the orientation, the single particles constituting the insulator layer are oriented, or the insulator layer is a single crystal. In this case, not only the interface of the insulator layer but also the insulator layer To be inside. In such a form, it is possible to further align the crystal orientation of the oriented magnetic particle group in the same orientation.

  The insulator layer as a whole is preferably parallel to the insulator layer and oriented in the same direction. Thereby, the magnetic particles to be deposited can also have anisotropy in a plane parallel to the insulator layer. Therefore, it is preferable to orient the insulator layer so that the easy axis of magnetization of the precipitated magnetic particles is parallel to the layer.

  Specifically, when the magnetic particles are cubic Ni particles, it is preferable to orient the Ni particles in the [111] direction parallel to the insulator layer (because it is cubic, the [111] direction is all equivalent) In any direction). When the magnetic particles are hexagonal Co particles, the Co particles are preferably oriented in the [001] direction. When the magnetic particles are Fe, the Fe particles are preferably oriented in the [100] direction (because they are cubic, the [100] direction is relaxed in all equivalent directions).

  For example, when Ni particles, which are magnetic particles, are deposited on an MgO solid solution (insulator layer), the Ni particles can be oriented and precipitated in the same direction by orienting the MgO solid solution in the [111] direction. Further, when Co is precipitated in the MgO-based solid solution (insulator layer), the Co is also precipitated in the same direction by orienting the MgO solid solution in the [111] direction. At this time, by selecting a reduction temperature and a cooling rate, Co can precipitate face-centered cubic Co which is a high-temperature phase. In this case, the lattice matching of the Co particles to the MgO solid solution can be made better than that of hexagonal Co.

In order to orient the insulator layer, for example, a method of forming a sheet using insulator particles having uniform shape anisotropy and crystal anisotropy can be employed. Examples of the method for measuring anisotropy include an X-ray diffraction method, an electron diffraction method using a transmission electron microscope, and the like. In the case of the X-ray diffraction method, measurement can be performed from the perpendicular direction (stacking direction) and the parallel direction with respect to the insulator layer, and the intensity ratio between the orientation peak and other peaks can be evaluated. That is, taking the [111] direction of the Ni example, (111) plane intensity (I _[111]) between the ratio of the other intensity _{(I other) (I [111} ] / (I [111] + I other) ). The ratio should be high, and the strength ratio is preferably 80% or more.

  Furthermore, the use of a single crystal insulator layer facilitates orientational precipitation of magnetic particles. By using the single-crystal insulator layer as the lowermost layer of the stacked body, it is possible to use this as a seed crystal to single-crystal the insulator layer thereon.

  According to such a configuration, the density of magnetic particles in the antenna substrate can be increased, the magnetization per volume can be increased, and the antenna substrate can be made thin.

  The plurality of magnetic particles 13 are embedded in the interface between the first and second insulator layers 11 and 12 with the predetermined orientation. The magnetic particles are simply embedded in the depressions on the surface of the insulator layer. Unlike those described above, it can be determined as a difference in TEM, diffraction image, and the like.

  The antenna 30 is made of, for example, stainless steel, Ag, Ni, Cu, Au, etc., and has a thickness of, for example, 15 to 100 μm.

  1 to 3 described above, at least one metal selected from Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf, and rare earth elements (including Y) ( The antenna substrate having the first and second insulator layers 11 and 12 made of ceramic layers having different compositions and containing an oxide of M1) has the magnetic particles 13 in a thermally stable state. It becomes possible to exist at the interface between the second insulator layers 11 and 12. As a result, when an electronic circuit board is arranged with the antenna device in the communication device described above, radio wave absorption by the electronic circuit board can be suppressed or prevented over a long period of time, and highly efficient transmission / reception is more stable. It is possible to realize the antenna device 1 including the antenna substrate 10 that can be performed at the same time.

  FIG. 4 is an enlarged cross-sectional view of a main part showing another form of the antenna substrate of the antenna device. In FIG. 4, the same members as those in FIG.

  In the antenna substrate 10, an organic resin layer 15 is formed on the second insulator layer 12 on the surface of the laminate 14. The plurality of magnetic particles 13 are disposed so as to be buried in both the second insulator layer 12 and the organic resin layer 15 at the bonding interface between the second insulator layer 12 and the organic resin layer 15. An antenna (not shown) is formed on the organic resin layer 15 of the antenna substrate 10. The magnetic particles 13 arranged at the bonding interface between the second insulator layer 12 and the organic resin layer 15 are oxides of the metal (M1) as ceramic layers located on the outermost surface of the laminate 14 in the manufacturing method described later. In addition to the above, a composition containing an oxide of magnetic metal (M2) can be formed by depositing the magnetic metal also from the ceramic layer located on the outermost surface during the reduction treatment.

  Examples of the organic resin include polystyrene, polyethylene, polyethylene terephthalate (PET), and epoxy resin.

  The antenna substrate 10 having the configuration shown in FIG. 4 can incline the dielectric constant between the second insulator layer 12 made of a ceramic layer positioned at the uppermost layer of the laminate 14 and the organic resin layer 15. For this reason, the antenna device including the antenna substrate 10 has higher transmission / reception efficiency with respect to high-frequency radio waves of 100 MHz to several GHz. In addition, by using the organic resin layer 15 on the surface of the antenna substrate 10 on which the antenna is formed, the antenna device 1 with improved durability against physical loads such as vibration can be realized. Furthermore, by using the organic resin layer 15 as the insulator layer, it is possible to reduce the weight of the antenna substrate 10 as compared with the case where the insulator layer is formed of only a ceramic layer.

As shown in FIG. 5, the plurality of magnetic particles 13 disposed at the interface between the second insulator layer 12 and the organic resin layer 15 have a surface embedded in the organic resin layer 15 with Al ₂ O ₃ , AlN, SiO ₂ , It is preferable to cover with a film 16 made of at least one inorganic material of Si ₃ N ₄ and SiC. According to such a configuration, the adhesion between the magnetic particles 13 and the organic resin layer 15 can be improved. In this case, the material of the film 16 is Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf constituting the second insulator layer 12 adjacent to the organic resin layer 15, and It is selected so as to be different from an oxide of at least one metal (M1) selected from rare earth elements (including Y).

  The thickness of the film 16 is preferably 1 to 5 nm regardless of the particle size of the magnetic particles 13. The magnetic particles 13 having the film 16 having such a thickness can maintain the high resistance of the antenna substrate 10 in addition to the improvement of the adhesion with the organic resin layer 15.

  FIG. 6 is an enlarged cross-sectional view of a main part showing another form of the antenna substrate of the antenna device. In FIG. 6, the same members as those in FIG.

  In the antenna substrate 10, an organic resin layer 15 in which a large number of inorganic material particles 17 are dispersed is formed on the second insulator layer 12 on the surface of the laminate 14. The plurality of magnetic particles 13 are disposed so as to be buried in both the second insulator layer 12 and the organic resin layer 15 at the bonding interface between the second insulator layer 12 and the organic resin layer 15. An antenna (not shown) is formed on the organic resin layer 15 of the antenna substrate 10. The magnetic particles 13 disposed at the bonding interface between the second insulator layer 12 and the organic resin layer 15 are formed by the same method as described for the antenna substrate of FIG.

  Examples of the organic resin include polystyrene, polyethylene, polyethylene terephthalate (PET), and epoxy resin as described above.

Examples of the inorganic material include ceramics such as Al ₂ O ₃ , MgO, and ZnO. The inorganic material particles 17 preferably have an average particle diameter of 10 to 1000 nm when the thickness of the organic resin layer 15 is 0.05 to 1000 μm. The inorganic material particles 17 having such an average particle diameter are preferably dispersed in the organic resin layer 15 at 20 to 90% by volume.

  The antenna substrate 10 having the configuration shown in FIG. 6 can incline the dielectric constant between the second insulator layer 12 made of a ceramic layer positioned at the uppermost layer of the laminate 14 and the organic resin layer 15. Further, the dielectric constant of the organic resin layer 15 can be controlled by adjusting the dispersion amount of the inorganic material particles 17 dispersed in the organic resin layer 15. For this reason, the antenna device provided with the antenna substrate 10 has higher magnetic permeability with respect to high-frequency radio waves of 100 MHz to several GHz. In addition, by using the organic resin layer 15 on the surface of the antenna substrate 10 on which the antenna is formed, an antenna device with improved durability against physical loads such as vibration can be realized.

  FIG. 7 is an enlarged cross-sectional view of a main part showing another form of the antenna substrate of the antenna device. In FIG. 7, the same members as those in FIG.

  In the antenna substrate 10, an organic resin layer 15 in which a large number of bubbles 18 are dispersed is formed on the second insulator layer 12 on the surface of the laminate 14. The plurality of magnetic particles 13 are disposed so as to be buried in both the second insulator layer 12 and the organic resin layer 15 at the bonding interface between the second insulator layer 12 and the organic resin layer 15. An antenna (not shown) is formed on the organic resin layer 15 of the antenna substrate 10. The magnetic particles 13 disposed at the bonding interface between the second insulator layer 12 and the organic resin layer 15 are formed by the same method as described for the antenna substrate of FIG.

  Examples of the organic resin include polystyrene, polyethylene, polyethylene terephthalate (PET), and epoxy resin as described above.

  The bubbles 18 preferably have an average diameter of 10 to 1000 nm when the thickness of the organic resin layer 15 is 0.05 to 1000 μm. The bubbles 18 having such an average diameter are preferably dispersed in the organic resin layer 15 in an amount of 5 to 50% by volume.

  The antenna substrate 10 configured as shown in FIG. 7 can incline the dielectric constant between the second insulator layer 12 made of a ceramic layer located at the uppermost layer of the laminate 14 and the organic resin layer 15. Further, the dielectric constant of the organic resin layer 15 can be controlled by adjusting the dispersion amount of the bubbles 18 dispersed in the organic resin layer 15. For this reason, the antenna device including the antenna substrate 10 has higher transmission / reception efficiency with respect to high-frequency radio waves of 100 MHz to several GHz. In addition, by using the organic resin layer 15 on the surface of the antenna substrate 10 on which the antenna is formed, an antenna device with improved durability against physical loads such as vibration can be realized. Furthermore, by using the organic resin layer 15 in which the bubbles 18 are dispersed as the insulator layer, the antenna substrate 10 can be further reduced in weight compared to the case where the insulator layer is formed only from the ceramic layer.

  FIG. 8 is an enlarged cross-sectional view of a main part showing another form of the antenna substrate of the antenna device. In FIG. 8, the same members as those in FIG.

  This antenna substrate 10 is formed with an organic resin layer 15 interposed between two laminated bodies 14. The plurality of magnetic particles 13 are formed at the bonding interface between the second insulator layer 12 and the organic resin layer 15 of one laminate 14 and at the bond interface between the second insulator layer 12 and the organic resin layer 15 of the other laminate 14. The two insulator layers 12 and the organic resin layer 15 are disposed so as to be buried in both. An antenna (not shown) is formed on the surface of one laminate 14 of the antenna substrate 10. Note that the magnetic particles 13 respectively disposed at the bonding interface between the second insulator layer 12 and the organic resin layer 15 of the two laminates 14 are formed by the same method as described above for the antenna substrate of FIG. .

  Examples of the organic resin include polystyrene, polyethylene, polyethylene terephthalate (PET), and epoxy resin as described above.

  The antenna substrate 10 configured as shown in FIG. 8 is improved in strength by the organic resin layer 15 disposed in the middle, and the dielectric constant can be controlled.

  In the antenna substrate 10 shown in FIGS. 4 to 8 described above, the plurality of magnetic particles 13 arranged at the bonding interface between the second insulator layer 11 and the organic resin layer 15 are preferably 1 to 100 nm, as described above. Preferably has a particle diameter of 10 to 50 nm and the distance between the magnetic particles 13 is 10 nm or less. The plurality of magnetic particles 13 have crystallinity such as single crystal or polycrystal, and the crystal orientation is aligned with at least two axes with respect to the crystal orientation of the second insulator layer 12. It is preferable to have.

  In the organic resin layer 15 of the antenna substrate 10 shown in FIG. 8 described above, inorganic material particles or bubbles may be dispersed as shown in FIGS.

  Next, antenna devices according to other embodiments will be described with reference to FIGS.

  The antenna device 1 shown in FIG. 9 has a structure in which, for example, the antenna 30 is embedded in the antenna substrate 10 shown in FIG.

  According to such a configuration shown in FIG. 9, since the antenna 30 is embedded in the antenna substrate 10, the retainability of the antenna 30 with respect to the antenna substrate is improved.

  An antenna device 1 shown in FIG. 10 includes, for example, an antenna substrate 10 in which the outer peripheral surface of the laminate 14 shown in FIG. 3 is covered with an exterior resin layer 19 and an antenna 30 formed on the exterior resin layer 19 of the antenna substrate 10. It consists of and. The exterior resin layer 19 is made of, for example, polystyrene, polyethylene, polyethylene terephthalate (PET), epoxy resin, or the like.

  According to the configuration shown in FIG. 10, since the antenna substrate 10 having a structure in which the laminate 14 is covered with the exterior resin layer 10 having a buffering action against an impact, the metal (M1) that is relatively weak against impact is oxidized. Compared to the case where the antenna substrate is configured only by the laminate 14 in which the first and second insulator layers made of the ceramic layer including the object are laminated, the antenna substrate has excellent durability against impact and the like. In addition, since the antenna substrate 10 has a high barrier property against moisture and the like due to the exterior resin layer 19, the antenna device 1 with long-term reliability can be realized.

  An antenna device 1 shown in FIG. 11 is formed on, for example, the antenna substrate 10 shown in FIG. 3 described above, a box-shaped organic resin spacer 20 formed on the antenna substrate 10 and having an opening at the bottom, and the spacer 20. And an antenna 30. The organic resin spacer 20 is made of, for example, polystyrene, polyethylene, polyethylene terephthalate (PET), epoxy resin, or the like.

  According to such a configuration shown in FIG. 11, by adjusting the height of the spacer 20 on which the antenna 30 is formed, the degree of entrainment of the radio wave by the antenna substrate 10 is controlled according to the frequency of the radio wave from the antenna 30. It becomes possible to do. As a result, when the electronic circuit board is disposed together with the antenna device 1 in the communication device, radio waves can be appropriately prevented from being absorbed by the electronic circuit board, and highly efficient transmission / reception can be performed.

  Next, a method for manufacturing an antenna device according to the embodiment will be described in detail with reference to FIGS.

(First step)
First, including a compound of at least one metal (M1) selected from the group of Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf and rare earth elements (including Y), First and second ceramic green sheets having different compositions and at least one containing a compound of magnetic metal (M2) such as Fe, Co, and Ni are formed.

  Specifically, a binder such as polyvinyl alcohol (PVA) is added to the metal (M1) compound, and the raw material is prepared by uniformly mixing with a ball mill composed of a resin ball or pot such as nylon. To do. By forming the raw material into a sheet, a first ceramic green sheet 41 shown in FIG. 12A containing the metal (M1) compound is produced.

  Further, a raw material is prepared by adding a binder such as polyvinyl alcohol (PVA) to the compound of the metal (M1) and the compound of the magnetic metal (M2) and mixing them uniformly by a ball mill. By forming the raw material into a sheet, a second ceramic green sheet 42 shown in FIG. 12B containing the metal (M1) compound and the magnetic metal (M2) compound is produced.

(Second step)
A plurality of the first and second ceramic green sheets are alternately laminated to produce a ceramic green sheet laminate. Specifically, as shown in FIG. 12C, the first and second ceramics are arranged such that the first ceramic green sheet 41 not containing the compound of the magnetic metal (M2) is located in the uppermost layer and the lowermost layer. A plurality of green sheets 41 and 42 are alternately laminated to produce a ceramic green sheet laminate 43.

(Third step)
The ceramic green sheet laminate 43 is degreased and fired to obtain a fired laminate 46 in which a plurality of first and second ceramic layers 44 and 45 shown in FIG. Make it.

(4th process)
By reducing the fired laminate 46, magnetic metal is precipitated from the oxide of the magnetic metal (M2) contained in the second ceramic layer 45 at the interface between the first and second ceramic layers 44 and 45. . By such reduction treatment, as shown in FIG. 13, at least one selected from Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf, and rare earth elements (including Y). The first insulator layer 11 composed of the first ceramic layer containing two metal (M1) oxides and the first insulator layer 11 are different in composition, and the second insulator layers 12 are alternately laminated and bonded, And the laminated body 14 arrange | positioned so that the some magnetic particle 13 may be buried in both of these 1st, 2nd insulator layers 11 and 12 in the junction interface of these 1st, 2nd insulator layers 11 and 12. FIG. The antenna substrate 10 containing can be manufactured. The second insulator layer 12 has a reduced amount of oxide of the magnetic metal (M2) or not at all compared to the second ceramic layer 45 depending on the amount of precipitation of the magnetic metal (M2). Become a composition. Thereafter, the antenna 30 is formed on the first insulator layer 11 on the uppermost layer of the antenna substrate 10 to manufacture the antenna device 1.

  Examples of the metal (M1) compound and the magnetic metal (M2) compound contained in the ceramic green sheets 41 and 42 in the first step include oxides, hydroxides, and carbonates. . Of these, oxides are preferable.

The second ceramic green sheet is preferably included in the form of a composite oxide in which an oxide of a magnetic metal (M2) containing at least one of Fe, Co, and Ni is dissolved in an oxide of the metal (M1). . As the oxide of the magnetic metal (M2), iron oxide (FeO), cobalt oxide (CoO), nickel oxide (NiO), etc. are easily dissolved in the metal (M1) oxide to form a composite oxide. Is preferable. For example, as iron oxide, there are various forms such as FeO, Fe ₂ O ₃ , Fe ₃ O _4, and iron monoxide (FeO) is dissolved in a wide composition range with the oxide of the metal (M1). This is preferable because a complex oxide is easily generated. For example, when MgO is used as the metal (M1) oxide and FeO is used as the magnetic metal (M2) oxide, the MgO and FeO are reacted to form, for example, a full solid solution (Fe—Mg—O based solid solution). The complex oxide can be produced. On the other hand, when Al ₂ O _{3 is} used as the oxide of the metal (M1) and Fe ₂ O ₃ is used as the oxide of the magnetic metal (M2), these Al ₂ O ₃ and Fe ₂ O ₃ are reacted. A composite oxide of all solid solution (Fe—Al—O) can be generated. The second ceramic green sheet may contain iron oxide having another valence other than FeO or Fe ₂ O ₃ as iron oxide.

  As described above, by using the second ceramic green sheet 42 containing the composite oxide, the first and second ceramic layers 44 and 45 convert the magnetic metal in the composite oxide in the reduction process of the fourth step. It can be easily deposited on the interface. In addition, the magnetic particles 13 can be deposited on the interface between the first and second ceramic layers 44 and 45 in a fine state. Furthermore, the crystal orientation of the precipitated magnetic particles 13 can be formed so as to be aligned with at least two axes with respect to the crystal orientation of the second ceramic layer 45 (second insulator layer 12). Furthermore, it becomes possible to deposit the magnetic particles 13 having a particle diameter of 1 to 100 nm on the interface between the first and second insulator layers 11 and 12 with a distance of 50 nm or less between them.

  When the metal (M1) and the magnetic metal (M2) are included in the form of a composite oxide as the second ceramic green sheet 42, the metal (M1) oxide is a mole, and the magnetic metal (M2) oxide. Is b mole, a: b is preferably 10:90 to 90:10. In the composite oxide, when the ratio of the magnetic metal (M2) oxide is larger than that of a: b = 10: 90, the crystal grains of the magnetic particles deposited by the reduction process increase, and the high frequency as the antenna substrate is increased. There is a risk that the characteristics will deteriorate. On the other hand, when the ratio of the metal (M1) oxide is larger than that of a: b = 90: 10 in the composite oxide, that is, when the ratio of the magnetic metal (M2) oxide is small, it is precipitated by the reduction step. There is a possibility that the number of magnetic particles is reduced and the magnetic interaction between the magnetic particles is lowered. Further, the deposited particles are less than 1 nm, and superparamagnetism is generated in some cases, resulting in deterioration of characteristics. More preferable a: b is 20:80 to 50:50.

  In particular, when the second ceramic green sheet 42 is contained in the form of a composite oxide using MgO as the oxide of the metal (M1) and FeO as the oxide of the magnetic metal (M2), the molar ratio of MgO: FeO. It is possible to easily produce a Mg—Fe—O based solid oxide composite oxide by reacting so that the ratio is 2: 1. By using the second ceramic ceramic green sheet containing such a composite oxide, the amount of the magnetic particles 13 deposited on the interface between the first and second ceramic layers 44 and 45 in the reduction process in the fourth step. Can be appropriately controlled, and coalescence and grain growth between the magnetic particles 13 can be suppressed.

The oxide of the magnetic metal (M2) is not limited to a single oxide but may be blended into the second ceramic green sheet 42 in the form of a composite oxide such as CoFe ₂ O ₄ and NiFe ₂ O _4. Allow. In particular, when an oxide of Ni and at least one metal of Fe and Co is selected to form a composite oxide, the amount of Ni is preferably 50 mol% or less with respect to Co and / or Fe.

  In the first step, the second ceramic green sheet 42 containing a compound of the magnetic metal (M2), preferably the metal (M1) and a composite oxide of the magnetic metal (M2) is magnetic during the reduction treatment. For the purpose of promoting the precipitation of particles, it is desirable that at least one additional metal (M3) selected from Al, Cr, Sc, Si, Mn, and B is further blended. As the additive metal (M3), a metal different from the metal (M1) is selected. The additive metal (M3) is preferably contained in the insulating layer (oxide) after the baking treatment in an amount of 0.01 to 0.25 atomic%.

  In the first step, the second ceramic green sheet 42 containing the compound of the magnetic metal (M2) is allowed to further contain Cu or Mn.

  In the second step, it is preferable that the first and second ceramic green sheets 41 and 42 are approximately 100 layers or more, depending on their thicknesses.

  In the third step, when the first and second ceramic green sheets 41 and 42 are made of an oxide raw material, firing is performed in an oxidizing atmosphere, in a vacuum, or in an inert atmosphere such as argon. It is preferable to heat to a temperature of ℃ or higher. On the other hand, when the first and second ceramic green sheets 41 and 42 are made of a raw material other than oxide, firing is preferably performed at a temperature of 1000 ° C. or higher in an oxidizing atmosphere. Examples of the oxidizing atmosphere include air, an inert gas atmosphere containing oxygen, and the like. When the first and second ceramic green sheets 41 and 42 are made of an oxide raw material, firing is preferably performed in an inert atmosphere or a vacuum in order not to change the amount of oxygen. For example, when the second ceramic green sheet 42 containing the metal (M1) and the composite oxide of the magnetic metal (M2) is used, the firing step is preferably performed in a vacuum or in an Ar atmosphere.

  In the fourth step, the reduction treatment is performed using a reducing gas such as hydrogen, carbon monoxide or methane, and hydrogen is particularly preferable. The reduction treatment temperature with hydrogen is not particularly limited as long as it is a temperature at which a part of the oxide of the second ceramic layer 45 constituting the fired laminate 46 is reduced, but is 200 to 1500 ° C. It is preferable to do. If the reduction treatment temperature is less than 200 ° C., the progress of the reduction reaction is delayed, and the productivity may be reduced. On the other hand, when the reduction treatment temperature exceeds 1500 ° C., the growth of the precipitated magnetic particles proceeds so much that the magnetic particles may aggregate with each other. A more preferable reduction treatment temperature is 200 to 1000 ° C.

  When hydrogen is used as the reducing gas, it is preferable to reduce by placing the fired laminate 46 in a hydrogen stream. If reduction is performed in a hydrogen stream in this way, magnetic particles can be uniformly deposited on the entire surface of the second ceramic layer 45 of the fired laminate 46 (the entire interface with the first ceramic layer 44). The flow rate of hydrogen is not generally limited by the reduction temperature, but is preferably set to 10 cc / min or more, for example.

  In the fourth step, the first insulator layer 11 adjacent to the second insulator layer 12 is made porous as shown in FIG. It is possible to promote the precipitation of the magnetic particles 13 by promoting the supply of the reducing gas (for example, hydrogen) to the substrate. However, if the antenna substrate is manufactured with the first insulator layer 11 left in a porous structure, long-term reliability may be reduced due to intrusion of moisture or the like. In such a case, it is preferable to inject and fill the organic resin 47 into the porous first insulator layer 11 as shown in FIG. The filling of the organic resin 47 can increase the adhesion strength between the porous first insulator layer 11 and the second insulator layer 12, and the magnetic particles 13 can be removed from the surface of the second insulator layer 12. It is possible to prevent the dropout. Further, the dielectric constant can be controlled by selecting the material of the organic resin 47.

  In the fourth step, the reduction treatment may be performed so that the total amount of the magnetic metal in the second ceramic layer 45 of the fired laminate 46 is deposited, or a part of the oxide of the magnetic metal is present in the ceramic layer 45, for example. The reduction treatment may be performed so as to remain as a solid solution composite oxide with the metal (M1).

  In the fourth step, the antenna 30 is formed by attaching a stainless steel, Cu, Ag, Ni, or Au metal plate to the laminate 14, applying a paste containing the metal, and drying, or using the metal. A method of forming a film by sputtering and patterning can be employed.

  In the first to fourth steps, the uppermost layer of the laminate 14 having the magnetic particles 13 and the lowermost first insulator layer 11 are formed of the first ceramic green sheet 41 not containing the compound of the magnetic metal (M2). If formed by firing, the magnetic particles can be prevented from being deposited on the surface of the first insulator layer 11. However, the first ceramic green sheet 41 also has a composition containing the compound of the magnetic metal (M2), and when the magnetic particles are deposited from the first insulator layer located at the uppermost layer and the lowermost layer of the laminate, an antenna is formed. If the magnetic particles are removed before, there will be no problem.

  The antenna substrate shown in FIGS. 4 to 8 described above can be manufactured by the following method.

1) Manufacturing method of antenna substrate shown in FIG. 4 First, the first ceramic green sheet containing the metal (M1) compound and the metal (M1) having a different composition from the metal (M1) compound of the first ceramic green sheet A second ceramic green sheet containing the compound and the compound of the magnetic metal (M2) is formed. A plurality of these first and second ceramic green sheets are alternately laminated so that the second ceramic green sheet is positioned at least on the uppermost layer to produce a ceramic green sheet laminate, and firing and reduction treatment are performed. A first insulator layer 11 containing an oxide of metal (M1) and a second insulator layer 12 having a composition different from that of the first insulator layer are alternately laminated and bonded, and the first and second insulators are laminated. A plurality of magnetic particles 13 are arranged at the bonding interface of the layers 11 and 12 so as to be buried in both the first and second insulator layers 11 and 12, and a plurality of magnetic particles 13 are further formed on the surface of the uppermost second insulator layer 12. The laminated body 14 in which the magnetic particles 13 are arranged so as to be buried in a part of the second insulator layer 12 is produced. Subsequently, the organic resin layer 15 is formed so as to include the plurality of magnetic particles 13 of the second insulator layer 12 located at the uppermost layer of the laminate 14 to produce the antenna substrate shown in FIG.

2) Manufacturing method of antenna substrate shown in FIG. 5 A stacked body 14 is manufactured by the same method as in 1) above, and includes a plurality of magnetic particles 13 of the second insulator layer 12 positioned at the uppermost layer of the stacked body 14. For example, Al or Si is sputtered on the surface to form an Al thin film or a Si thin film (not shown). Subsequently, the first heat treatment is performed to dissolve the Al thin film or the Si thin film in the plurality of magnetic particles 13, and then the second heat treatment (oxidation treatment, nitridation treatment, carbonization treatment) is performed to thereby obtain the surface of the second insulator layer. A film 16 of any one of Al ₂ O ₃ , AlN, SiO ₂ , Si ₃ N ₄ , and SiC is formed on the surface of the magnetic particles 13 protruding from 12. The first heat treatment is not limited as long as the magnetic particles do not oxidize and can be dissolved in Al, Si, Al—Si, but in a range of 200 to 1000 ° C. in an inert gas atmosphere such as Ar. It is preferable to heat with. Further, the amount of the solid solution takes into consideration the thickness of any film of Al ₂ O ₃ , AlN, SiO ₂ , Si ₃ N ₄ , or SiC generated by the subsequent second heat treatment (oxidation treatment, nitridation treatment, carbonization treatment). And decide. For example, Al can be dissolved in a solid solution up to about 53% by atomic weight ratio with respect to Fe magnetic particles, but by dissolving 53% Al in Fe magnetic particles having a particle size of 10 nm, An Al ₂ O ₃ film of about 1 nm can be formed on the surface of the magnetic particles by the second heat treatment in an oxidizing atmosphere. Further, by dissolving 20% of Al in the magnetic particles of Fe having a particle size of 100 nm, an Al ₂ O ₃ film of about 5 nm is formed on the surface of the Fe magnetic particles by a second heat treatment in an oxidizing atmosphere thereafter. Can be formed.

  Next, the organic resin layer 15 is formed on the second insulator layer 12 from which the plurality of magnetic particles 13 covered with the various films 16 are projected, thereby producing the antenna substrate 10 shown in FIG.

3) Manufacturing method of antenna substrate shown in FIG. 6 A stacked body 14 is manufactured by the same method as in 1) above, and includes a plurality of magnetic particles 13 of the second insulator layer 12 positioned at the uppermost layer of the stacked body 14. By forming the organic resin layer 15 in which a large number of inorganic material particles 17 are dispersed on the surface, the antenna substrate 10 shown in FIG. 6 is manufactured.

4) Manufacturing method of antenna substrate shown in FIG. 7 A stacked body 14 is manufactured by the same method as in 1) above, and includes a plurality of magnetic particles 13 of the second insulator layer 12 positioned at the uppermost layer of the stacked body 14. By forming the organic resin layer 15 in which a large number of bubbles 18 are dispersed on the surface, the above-described antenna substrate 10 shown in FIG. 7 is manufactured.

4) Method for manufacturing antenna substrate shown in FIG. 8 Two stacked bodies 14 are manufactured by the same method as in 1) above, and the second insulator layers 12 in which a plurality of magnetic particles 13 are embedded are stacked on each other. The antenna substrate 10 shown in FIG. 8 is manufactured by arranging the organic resin layers 15 so as to face each other and sandwiching the organic resin layer 15 between them.

  Next, a typical application example of the antenna device according to the embodiment will be described with reference to the drawings.

  FIG. 16 is a front view showing a form in which the antenna device shown in FIGS. 1 to 3 is incorporated in an electronic circuit board. In this antenna device 1, the arrangement method of a plurality of magnetic particles located on the bonding interface of the first and second insulator layers constituting the antenna substrate 10 on the electronic circuit substrate 50 is substantially parallel to the surface of the electronic circuit substrate 50. It is preferable to arrange so that

  According to the configuration shown in FIG. 16, when the antenna 30 transmits or receives high-frequency radio waves of 100 MHz to several GHz, absorption of radio waves at the electronic circuit board 50 located on the back side of the antenna 30 is suppressed. Or it can prevent, and it becomes possible to perform highly efficient transmission / reception.

  That is, when the antenna is disposed in the vicinity of the electronic circuit board without the antenna board, high-frequency radio waves transmitted or received by the antenna are absorbed by the electronic circuit board. Further, an eddy current is generated by the absorption of radio waves by the electronic circuit board, and the magnetic field from the antenna is canceled by the magnetic field of the eddy current. That is, the radio wave is canceled. Therefore, the absorption of radio waves by the electronic circuit board doubles the radio waves transmitted or received by the antenna.

  A plurality of first and second insulator layers 11 and 12 shown in FIGS. 1 to 3 are stacked and bonded, and a plurality of magnetic particles 13 are attached to the interface between the first and second insulator layers 11 and 12. The antenna substrate 10 according to the embodiment composed of the laminated body 14 embedded and arranged has high magnetic permeability with respect to radio waves of 100 MHz to several GHz and high frequency transmitted or received by the antenna. For this reason, the high frequency radio wave transmitted or received by the antenna 30 is wound toward the antenna substrate 10 and the radio wave can be suppressed or prevented from reaching the electronic circuit board 50. That is, the radio wave can be suppressed or prevented from being absorbed by the electronic circuit board 50. Further, by suppressing or preventing radio wave absorption in the electronic circuit board 50, it is possible to suppress or prevent generation of eddy currents in the electronic circuit board 50 and generation of electric fields due to magnetic fields of the eddy currents. As a result, it is possible to suppress or prevent this electric field from canceling the electric field at the antenna 30. Therefore, the antenna device 1 according to the embodiment suppresses or prevents absorption of the radio wave transmitted or received by the antenna 30 in the electronic circuit board 50 and cancels the electric field of the antenna 30 accompanying the radio wave absorption in the electronic circuit board 50. Therefore, highly efficient transmission / reception can be performed.

  17 is a perspective view showing a mobile phone equipped with the antenna device according to the embodiment shown in FIGS. 1 to 3, FIG. 18 is a front view showing the mobile phone of FIG. 17, and FIG. 19 is a mobile phone of FIG. FIG.

  The mobile phone 60 has a housing 61. The liquid crystal display member 62 and the input member 63 are disposed on the surface side of the casing 61. The electronic circuit board 64 is disposed in the casing 61 so as to be positioned on the back side of the liquid crystal display member 62 and the input member 63. The antenna device 1 according to the embodiment is disposed in the casing 61 in contact with the back surface of the electronic circuit board 64.

  According to such a configuration, high-frequency radio waves of 100 MHz to several GHz transmitted or received by the antenna 30 of the antenna device 1 incorporated in the housing 61 when using the mobile phone 60 are shown in FIG. As described above, absorption by the electronic circuit board 64 can be suppressed or prevented, so that highly efficient transmission can be performed.

  FIG. 20 is a perspective view showing a personal computer equipped with the antenna device according to the embodiment shown in FIGS.

  In the personal computer 70, a display side casing 72 is attached to an input side casing 71 so as to be opened and closed by a hinge mechanism (not shown). The input member 73 is disposed in the input side casing 71. A display member 74 having an electronic circuit board (not shown) is disposed in the display-side casing 72. The antenna device 1 according to the embodiment is disposed inside the display-side casing 72 so as to be located on the back side of the display member 74. The antenna device 1 is arranged so that an antenna substrate (not shown) is positioned on the display member 74 side, and the antenna is positioned on the opposite side of the display member 74 with the antenna substrate sandwiched between the antenna substrate surface. Is formed.

  According to such a configuration, when the personal computer 70 is used, high-frequency radio waves of 100 MHz to several GHz transmitted or received by the antenna of the antenna device 1 mounted on the display-side casing 72 are the above-described FIG. As described above, the absorption by the electronic circuit board incorporated in the display member 74 can be suppressed or prevented. As a result, the influence of radio waves on the display member 74 (including the electronic circuit board) can be suppressed or prevented, so that the personal computer 70 capable of highly efficient transmission / reception can be realized.

  As described above, by applying the antenna device 1 according to the embodiment to an electronic device as shown in FIGS. 16 to 20, it is possible to suppress transmission loss of radio waves, and thus it is possible to save space of the antenna device itself. The electronic device to be incorporated can be reduced in size and thickness.

  Examples of the present invention will be described below.

(Example 1)
First, MgO powder and FeO powder are weighed and mixed with a coarse machine, then calcined in air at 800 ° C. for 2 hours to completely dissolve MgO and FeO (Fe _0.6 Mg _0.4 ) O composite oxide A powder was obtained. This composite oxide powder was mixed with an acetone, methyl ethyl ketone (MEK), glycerin, polyvinyl butyral (PVB), and dibutyl phthalate (DBP) by a ball mill (1 hour, rotation speed: 300 rpm) to form a slurry. The obtained slurry was formed on a polyethylene terephthalate (PET) film having a thickness of 50 μm with a micro gravure coater, and then dried through a drying zone set at 60 ° C. and 70 ° C. (Fe _0.6 Mg _0.4 ) O. A 1 μm-thick second ceramic green sheet containing 95% by weight of powder was obtained.

Further, Al ₂ O ₃ powder was formed into a sheet by the same method to obtain a first ceramic green sheet having a thickness of 1 μm and containing 90% by weight of Al ₂ O ₃ powder.

<Laminated body production>
Next, the first and second ceramic green sheets are laminated so that the first ceramic green sheets (ceramic green sheets containing Al ₂ O ₃ ) are alternately arranged on the outermost layer while peeling the PET green film from the PET film. Thus, a 603-layer ceramic green sheet laminate was produced.

The obtained ceramic green sheet laminate is hydrostatically laminated at 240 kg / cm ² , cut into a predetermined size, degreased at 500 ° C. for 1 hour in an Ar atmosphere, and further fired at 1300 ° C. for 1 hour. Thus, a multilayer ceramic plate was produced.

Next, the multilayer ceramic plate is placed in a hydrogen furnace, reduced at 800 ° C. for 10 minutes while flowing 9cc of hydrogen gas with a purity of 99.9% per minute, and then cooled in the furnace to form a plurality of Fe nanoparticles. An antenna substrate deposited on the interface between the first insulator layer made of Al ₂ O ₃ and the _second insulator layer made of Fe—Mg—O-based composite oxide was produced. The Fe particles deposited by peeling off the antenna substrate layer were observed with a scanning electron microscope (SEM). As a result, 50-100 nm Fe particles were buried in the ceramic surface and deposited innumerably. At this time, the interval between the Fe particles was 10 to 30 nm.

  Next, an antenna device was manufactured by forming an antenna by a printing method using silver paste on one surface of the antenna substrate.

(Example 2)
An antenna is produced in the same manner as in Example 1 except that the first ceramic green sheet containing 90% by weight of Al ₂ O ₃ powder and the second ceramic green sheet containing 95% by weight of (Fe _0.6 Co _0.2 Mg _0.2 ) O powder are used. A substrate was fabricated, an antenna was formed, and an antenna device was manufactured.

(Example 3)
The same method as in Example 1 except that the first ceramic green sheet containing 90% by weight of Al ₂ O ₃ powder and the second ceramic green sheet containing 95% by weight of (Fe _0.5 Co _0.15 Ni _0.05 Mg _0.2 ) O powder were used. Thus, an antenna substrate was manufactured, an antenna was formed, and an antenna device was manufactured.

(Example 4)
An antenna substrate was produced in the same manner as in Example 1 except that the first ceramic green sheet containing 85 wt% of SiO ₂ powder and the second ceramic green sheet containing 95 wt% of (Fe _0.6 Mg _0.4 ) O powder were used. An antenna device was manufactured by forming an antenna.

(Example 5)
Example 1 except that a first ceramic green sheet containing 95% by weight of (Co _0.3 Al _0.7 ) ₂ O ₃ powder and a _second ceramic green sheet containing 95% by weight of (Fe _0.6 Mg _0.4 ) O powder were used. An antenna substrate was manufactured by the method, an antenna was formed, and an antenna device was manufactured.

(Example 6)
The first ceramic green sheet containing 90% by weight of Al ₂ O ₃ powder and the second ceramic green sheet containing 95% by weight of mixed powder of (Fe _0.6 Mg _0.4 ) O + 0.01% by weight B ₂ O ₃ were used. An antenna substrate was manufactured by the same method as in Example 1, an antenna was formed, and an antenna device was manufactured.

(Example 7)
Two 200-layer stacks in which a plurality of Fe nanoparticles were buried at the interface between the first and second insulator layers similar to Example 1 were produced. In addition, a 201-layer laminate in which a plurality of Fe nanoparticles were embedded in the interface between the first and second insulator layers similar to Example 1 was produced. The 201-layer laminate was provided with a second insulator layer in which a plurality of Fe nanoparticles were deposited on the outermost layer. Subsequently, with the 201 layer stack as the center, the 200 layer stack is arranged above and below the second layer so that the second insulator layer on which the plurality of Fe nanoparticles are deposited faces the 201 layer stack. These laminates were bonded and laminated with an epoxy resin layer having a thickness of 10 μm to produce a 603-layer antenna substrate. Thereafter, an antenna was formed on the antenna substrate by the same method as in Example 1 to manufacture the antenna substrate.

(Example 8)
A 603-layer laminate in which a plurality of Fe nanoparticles are embedded at the interface between the first and second insulator layers similar to that in Example 1 is dip-coated on a urethane resin solution, and the outer peripheral surface is a urethane resin having a thickness of 100 μm. An antenna substrate covered with layers was produced. Thereafter, an antenna device was manufactured by attaching a copper foil (antenna) to the antenna substrate.

Example 9
An antenna device is manufactured by mounting a box-shaped epoxy resin spacer having a thickness of 0.3 mm and a height of 1 mm on the same antenna substrate as in Example 1 and placing a copper plate (antenna) on the spacer. did.

  In addition, the state of the precipitated particles (magnetic particles) in Examples 2-5 and 7-9 was not significantly different from that in Example 1. However, in the antenna substrate of Example 6, the particle size of the precipitated particles (magnetic particles) was 10-30 nm, and the particle interval was 10-30 nm.

(Example 10)
An acicular (Fe _0.7 Mg _0.3 ) solid solution powder having an average diameter of 100 nm and an average length of 1 μm, and a spherical (Fe _0.7 Mg _0.3 ) solid solution powder having an average particle size of 50 nm are mixed with acetone, methyl ethyl ketone. (MEK), glycerin, polyvinyl butyral (PVB), dibutyl phthalate (DBP) and a ball mill (10 minutes, 60 rpm) were mixed to form a slurry. The obtained slurry was subjected to sheet molding on a polyethylene terephthalate (PET) film having a thickness of 50 μm with a micro gravure coater, and then dried through a drying zone set at 60 ° C. and 70 ° C. (Fe _0.7 Mg _{0 .3} ) A second ceramic green sheet having a thickness of 1 μm containing 95% by weight of O powder was obtained.

Further, Al ₂ O ₃ powder was formed into a sheet by the same method to obtain a first ceramic green sheet having a thickness of 1 μm and containing 90% by weight of Al ₂ O ₃ powder.

<Laminated body production>
Next, the first and second ceramic green sheets are laminated so that the first ceramic green sheets (ceramic green sheets containing Al ₂ O ₃ ) are alternately arranged on the outermost layer while peeling the PET green film from the PET film. Thus, a 603-layer ceramic green sheet laminate was produced.

The obtained ceramic green sheet laminate is hydrostatically laminated at 240 kg / cm ² , cut into a predetermined size, degreased at 500 ° C. for 1 hour in an Ar atmosphere, and further fired at 1300 ° C. for 1 hour. Thus, a multilayer ceramic plate was produced.

  When the layer was peeled from the multilayer ceramic plate and observed with a scanning electron microscope (SEM), the second insulator layer made of the Fe—Mg—O-based composite oxide had the longitudinal direction of the acicular particles as a layer. It was found to have a texture oriented in one parallel direction. Moreover, as a result of the structural analysis by the X-ray diffraction method, it was found that the [001] direction was oriented in the longitudinal direction of the acicular particles. When the degree of orientation was evaluated from the peak intensity ratio between the (001) plane and other planes, it was found to be 90% or more.

Next, the multilayer ceramic plate is placed in a hydrogen furnace, reduced at 850 ° C. for 10 minutes while flowing 9cc of hydrogen gas with a purity of 99.9%, and then cooled in the furnace, whereby a plurality of Fe nanoparticles are obtained. An interface between the first insulator layer made of Al ₂ O ₃ and the second insulator layer made of Fe—Mg—O-based composite oxide, and a substrate deposited in the Fe—Mg—O-based composite oxide layer are prepared. did.

The Fe particles deposited by peeling off the substrate layer were observed with a scanning electron microscope (SEM). As a result, countless Fe particles of 10 to 20 nm were deposited on the ceramic surface and inside. The spacing between the Fe particles at this time was 5 to 10 nm including the inside of the grains.

  Further, the orientation of Fe particles in the direction parallel to and perpendicular to the layer was evaluated from the peeled sample by X-ray diffraction. As a result, the [100] orientation of the Fe particles and the Fe—Mg—O based composite oxide is oriented in the direction perpendicular to the layer, and the Fe particles and the Fe—Mg—O based composite oxide layer [ It was found that the [001] orientation was oriented and had uniaxial anisotropy. The degree of orientation of Fe particles in the direction parallel to and perpendicular to the layer was evaluated. As a result, the degree of orientation was 90% or more.

  Next, an antenna device was manufactured by arranging the antenna substrate so that the [100] direction was orthogonal to the magnetic field direction and forming an antenna.

(Comparative Example 1)
An antenna device was manufactured by the same method as in Example 1 except that an MgO ceramic plate was used instead of the antenna substrate in Example 1.

(Comparative Example 2)
An antenna device was manufactured in the same manner as in Example 1 except that a magnetic member in which iron fine particles were dispersed in an epoxy resin was used instead of the antenna substrate in Example 1.

(Comparative Example 3)
An antenna device was manufactured by the same method as in Example 1 except that a NiZn ferrite sintered body was used instead of the antenna substrate in Example 1.

  The antenna devices of Example 1-10 and Comparative Example 1-3 were mounted on a cellular phone as shown in FIGS. 16 to 18 described above, and the radiated electromagnetic field was measured by the following method.

<Measurement of radiated electromagnetic field>
The reception level of vertically polarized waves was measured with a receiving antenna disposed at a position 3 m from the mobile phone for radio waves transmitted in the anechoic chamber. At this time, a phantom is arranged on the side of the mobile phone facing the human body, coordinates are set so that the phantom side is 0 to 180 °, and the opposite side of the phantom is 180 to 360 °, and a 1.8 GHz radiated electromagnetic field wave is generated. Level (reception level) measurement was performed. Further, gain improvement at 270 ° with Comparative Example 1 as a reference value was obtained.

The results are shown in Table 1 below.

  As apparent from Table 1, the antenna device of Example 1-10 has a higher reception level at 180 ° to 360 ° (0 °) on the opposite side of the human body than the antenna device of Comparative Example 1-3. Recognize. As for the reception level (gain improvement) at 270 °, when the antenna device of Comparative Example 1 was used as a reference, it was confirmed that the antenna device of Example 1-9 had an improvement in reception level of 5 dB or more. In addition, the antenna device of Example 1-9 was confirmed to have an improvement in reception level of 1 dB or more as compared with the antenna devices of Comparative Examples 2 and 3.

The top view which shows the antenna device which concerns on embodiment of this invention. The front view which shows the antenna device of FIG. The expanded sectional view which shows the antenna board | substrate of FIG. The expanded sectional view which shows the antenna board | substrate of the antenna device which concerns on other embodiment of this invention. The expanded sectional view which shows the antenna board | substrate of the antenna device which concerns on other embodiment of this invention. The expanded sectional view which shows the antenna board | substrate of the antenna device which concerns on other embodiment of this invention. The expanded sectional view which shows the antenna board | substrate of the antenna device which concerns on other embodiment of this invention. The expanded sectional view which shows the antenna board | substrate of the antenna device which concerns on other embodiment of this invention. Sectional drawing which shows the antenna device which concerns on other embodiment of this invention. Sectional drawing which shows the antenna device which concerns on other embodiment of this invention. Sectional drawing which shows the antenna device which concerns on other embodiment of this invention. Sectional drawing which shows the manufacturing process of the antenna device which concerns on embodiment of this invention. Sectional drawing which shows the manufacturing process of the antenna device which concerns on embodiment of this invention. The principal part expanded sectional view which shows the state in which a magnetic particle precipitates on the insulator layer which has a porous structure. The principal part expanded sectional view which shows the state which injected the organic resin into the insulator layer which has a porous structure after magnetic particle precipitation. The front view which shows the electronic circuit board in which the antenna device which concerns on embodiment was integrated. The perspective view which shows the mobile telephone by which the antenna device which concerns on embodiment is mounted. The front view of FIG. The side view of FIG. The perspective view of the personal computer by which the antenna device which concerns on embodiment is mounted.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Antenna device, 10 ... Antenna board | substrate, 11 ... 1st insulator layer, 12 ... 2nd insulator layer, 13 ... Magnetic particle, 14 ... Laminated body, 15 ... Organic resin layer, 17 ... Inorganic material particle, 18 ... Air bubbles, 19 ... exterior resin layer, 20 ... organic resin spacer, 30 ... antenna, 41 ... first ceramic green sheet, 42 ... second ceramic green sheet, 43 ... ceramic green sheet laminate, 44 ... first ceramic layer, 45 ... second ceramic layer.

Claims (18)

An antenna substrate comprising: a plurality of bonded insulator layers; and a plurality of magnetic particles disposed so as to be buried in both of the insulator layers forming the interface at a bonded interface between these insulator layers ; and An antenna placed directly on the main surface or close to the main surface;
Equipped with a,
The plurality of insulator layers are oxides of at least one metal selected from Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf, and rare earth elements (including Y). And a ceramic layer containing an oxide of a magnetic metal, the composition is different between adjacent layers, and
The antenna device according to claim 1, wherein the ceramic layer is included in the form of a complex oxide in which the metal and the magnetic metal are dissolved . An antenna substrate including a plurality of bonded insulator layers and a plurality of magnetic particles disposed so as to be buried in both of the insulator layers forming the interface at the bonding interface of these insulator layers; and
An antenna disposed directly on or near the principal surface of the antenna substrate;
With
The arbitrary layer of the plurality of insulator layers is at least selected from Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf, and rare earth elements (including Y). A ceramic layer containing one metal oxide, the remaining layers being selected from Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf, and rare earth elements (including Y) A ceramic layer comprising at least one metal oxide and a magnetic metal oxide, and the composition is different between adjacent layers,
Among the insulator layers forming a bonding interface in which a plurality of the magnetic particles are arranged, at least one layer is a ceramic layer containing the metal oxide and the magnetic metal oxide, and
The antenna device, wherein the ceramic layer including the metal oxide and the magnetic metal oxide is included in the form of a composite oxide in which the metal and the magnetic metal are solid-dissolved. The antenna device according to claim 1 or 2, wherein the insulator layer located on the front surface side among the plurality of insulator layers is an organic resin layer. The antenna device according to claim 1 or 2, wherein an insulator layer located in the middle among the plurality of insulator layers is an organic resin layer. The antenna device according to claim 3 or 4, wherein the organic resin layer contains dispersed inorganic material particles or bubbles. The plurality of magnetic particles embedded in the organic resin layer are made of Al. ₂ O _Three , AlN, SiO ₂ , Si _Three N _Four 4. The antenna device according to claim 3, wherein the antenna device is coated with a film made of at least one inorganic material of SiC and SiC. The plurality of magnetic particles have crystallinity, and the crystal orientation thereof is aligned with at least two axes with respect to the crystal orientation of the particles constituting at least one of the insulator layers in which the magnetic particles are buried. The antenna device according to claim 1 or 2, characterized in that: The antenna device according to claim 7, wherein the insulator layer is composed of a polycrystalline orientation layer or a single crystal layer. The antenna device according to claim 7, wherein an interface between the particles constituting the insulator layer and the magnetic particles is lattice-matched. 3. The antenna device according to claim 1, wherein the plurality of magnetic particles have a particle diameter of 1 to 100 nm and are arranged at a bonding interface of each insulator layer with an interval of 50 nm or less. A plurality of the arbitrary insulator layers and the remaining insulator layers are alternately laminated and bonded, and a plurality of the magnetic particles having a particle diameter of 1 to 100 nm are spaced at an interval of 50 nm or less at the bonding interface of these insulator layers. 3. The antenna according to claim 2, wherein a metal that is embedded and arranged and is included in the form of an oxide in the remaining insulator layer is different from a metal that is included as an oxide in the arbitrary insulator layer. device. The antenna device according to claim 1, wherein the antenna substrate includes an exterior resin layer further formed on an outer peripheral surface of the plurality of insulator layers. 3. The antenna device according to claim 1, wherein an organic resin spacer having a lower opening is further disposed on the antenna substrate, and the antenna is formed on the spacer. (A ) a compound of at least one metal selected from the group consisting of Mg, Al, Si, Ca, Cr, Ti, Zr, Ba, Sr, Zn, Mn, Hf and rare earth elements (including Y), and a composition of each other Forming first and second ceramic green sheets that are different from each other and at least one of them contains a magnetic metal compound;
(B) a step of alternately laminating a plurality of the first and second ceramic green sheets;
( C) firing the ceramic green sheet laminate to produce a fired laminate in which a plurality of first and second ceramic layers are alternately laminated and bonded; and ( d) reducing the fired laminate. The step of precipitating the magnetic metal from the ceramic layer containing the oxide of the magnetic metal out of the first and second ceramic layers at the interface between the first and second ceramic layers
A method for manufacturing an antenna device, comprising: The ceramic green sheet containing the compound of the magnetic metal among the first and second ceramic green sheets includes the metal and the magnetic metal in the form of a complex oxide. Manufacturing method of antenna device. 16. The composite oxide of the metal and the magnetic metal, wherein the metal oxide and the magnetic metal oxide are mixed in a molar ratio of 1: 9 to 9: 1. The manufacturing method of the antenna device of description. Of the first and second ceramic green sheets, the ceramic green sheet containing the compound of the magnetic metal further has at least one additional metal element selected from Al, Cr, Sc, Si, Mn, and B as the metal. The method for manufacturing an antenna device according to claim 14, wherein the metal is selected as a different metal and contained in an amount of 0.01 to 0.25 atomic%. The method for manufacturing an antenna device according to claim 14, wherein the reduction treatment is performed under a temperature condition of 200 to 1500 ° C in a hydrogen atmosphere.

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