JP6239176B1 - Antenna module - Google Patents

Abstract

A chip antenna and an antenna module in which the volume of a magnetic material is increased to the maximum with respect to the installation area while saving space are obtained. A magnetic core having a recess only on the bottom surface is prepared, and an antenna pattern is directly provided on the surface to obtain a chip antenna. Both the start and end of the antenna pattern are provided on the bottom surface, and the start of the antenna pattern bypasses the plane in a plane. An antenna module is formed by placing the chip antenna on a substrate on which an electronic component is placed on the upper surface so as to cover the electronic component and placing the chip antenna on the upper surface of the substrate via the bottom surface of the chip antenna. Get. [Selection] Figure 6

Description

  The present invention relates to an antenna module that transmits and receives radio waves.

  With the spread of products with IC functions such as IC tags, many NFC chip antennas and antenna modules have been developed.

In particular, in the fields of cellular phones, personal computers, etc., it is desired to reduce the size and thickness of NFC antennas and antenna modules as products become smaller and thinner.

In response to such a demand, the present inventors prepare a core 42 having an opening 41 as shown in FIG. 10 that can enclose an electronic component as shown in Patent Document 1, and winding a lead wire 43 as shown in FIG. We have invented and filed an attached chip antenna 44 and an antenna module 47 which is mounted on a substrate 45 and contains an electronic component 46.

JP-A-2006-59035

However, in Patent Document 1, since the conducting wire is wound around the core, the area of the core in the horizontal section corresponding to the thickness of the conducting wire (hereinafter referred to as “horizontal sectional area”) with respect to the installation area where the antenna can be installed. ) Is reduced, and a high-performance antenna cannot be obtained. Also, if the lead wire is exposed in the lateral direction, there is no picking part when mounting, especially when using a mounting machine, so a case made of a material that does not interfere with radio waves such as non-magnetic materials and non-conductors ( It was necessary to protect the lead wire and secure the portion to be picked. Therefore, the horizontal cross-sectional area of the core is further reduced by the amount of the case. Also, when an antenna is used as the receiving side, it is often used without an external power supply. Therefore, it is necessary to pick up radio waves and convert them to electrical signals without any waste. Floats, slight gaps between the outer conductor and core when wound horizontally or double, triple when stacked vertically or vertically in addition to double or triple in the horizontal direction There was a desire to eliminate even a loss caused by a gap between the upper outer conductor and the core, winding disturbance of the conductor (wire conductor), and the like. In particular, the turbulence of the wire conductor also causes a variation in performance without fixing the position of the wire conductor.

Therefore, the present invention improves the antenna performance by increasing the horizontal cross-sectional area of the magnetic body relative to the installation area and increasing the volume of the magnetic body (first object), and makes the conductor and the magnetic body as close as possible. Thus, it is an object to further improve the antenna performance (second purpose) by eliminating the loss due to the conducting wire.

As a result of intensive development by the present inventors in order to achieve the above two objects, it has been found that the above structure can be achieved.

That is, the electronic component includes a columnar magnetic core placed on a substrate on which a top surface is mounted via a bottom surface, and an antenna pattern directly provided on the surface of the core. The chip antenna is characterized in that a concave portion opened only on the bottom surface side is provided to accommodate components, thereby increasing the horizontal sectional area of the magnetic body relative to the installation area and increasing the volume of the magnetic body. Antenna performance can be improved.

Furthermore, when the antenna pattern is a chip antenna provided from the top surface of the core through the side surface to the bottom surface, the antenna installation area can be used to the maximum extent possible.

Furthermore, the antenna pattern can be directly fixed to the substrate by using a chip antenna having both a start end and a termination end on the bottom surface of the core. In the present invention, “starting end” means an end on the inner peripheral side of the antenna pattern, and “termination” means an end on the outer peripheral side of the antenna pattern.

Further, the antenna pattern is wound one or more times, and has a detour that detours inward from the start end on the bottom surface of the core, so that the antenna patterns can be crossed in three dimensions to draw out the start end. No insulator is required.

  By making the bypass route directly provided on the bottom surface of the core and making the start end planarly bypass the bottom surface in the inner direction of the core on the bottom surface, the complexity of manufacturing the chip antenna is eliminated. .

Further, in the antenna pattern, a portion provided on the upper surface of the core is a chip antenna provided only in a portion excluding the central portion among nine equal parts obtained by dividing the upper surface into three equal parts vertically and horizontally. As a result, the performance of the antenna can be improved efficiently.

Furthermore, when the thickness of the antenna pattern is 0.3 to 0.7 mm, the number of turns and the L value can be easily adjusted.

Furthermore, when the interval between adjacent patterns of the antenna pattern is 0.1 to 0.4 mm, the antenna pattern can be prevented from approaching the vicinity of the center.

The present inventors also include a substrate, an electronic component placed on the top surface of the substrate, a magnetic core placed on the top surface of the substrate via a bottom surface, and directly on the surface of the core. By providing an antenna module, wherein the core is provided with a recess opened only on the bottom surface side, and the electronic component is housed in the recess. It was found that an antenna module resistant to noise can be obtained.

Since the antenna pattern is an antenna module provided from the upper surface of the core to the side surface through the side surface, the antenna installation area can be used most effectively.

  Furthermore, the antenna pattern can be directly fixed to the substrate by using an antenna module in which the start and end of the antenna pattern are provided on the bottom surface of the core.

Furthermore, the antenna patterns are wound one or more times, and the antenna patterns are not short-circuited by using an antenna module having a detour that detours inward from the start end on the bottom surface of the core.

Further, the bypass circuit is provided directly on the bottom surface of the core, and the antenna module is configured such that the start end and the end are planarly bypassed in the inner direction of the core on the bottom surface. In order to pull out, it is not necessary to insulate the antenna pattern and cross it three-dimensionally.

Furthermore, when the detour is an antenna module provided on the substrate, the detour can be created even if the number of rounds of the antenna pattern on the upper surface of the core is increased.

Further, in the antenna pattern, a portion provided on the upper surface of the core is an antenna module provided only in a portion excluding the central portion among nine equal parts obtained by dividing the upper surface into three equal parts. As a result, the performance of the antenna can be improved efficiently.

Furthermore, when the thickness of the antenna pattern is 0.3 to 0.7 mm, the number of turns and the L value can be easily adjusted.

Furthermore, when the interval between adjacent patterns of the antenna pattern is 0.1 to 0.4 mm, the antenna pattern can be prevented from approaching the vicinity of the center.

Furthermore, when the substrate has an antenna module having a slit having a predetermined length from the side end face, the antenna module is hardly broken even if a product to be attached is deformed by heat or external force.

Furthermore, by forming an antenna module having a gap between the substrate and the core, when the substrate and the core are soldered and when the antenna module is soldered to a product, deformation due to thermal expansion of air inside the core And can prevent damage.

  According to the present invention, it is possible to increase the performance of an antenna and an antenna module using the same by increasing the volume of the magnetic body without changing the installation area and further bringing the conductor and the magnetic body into close contact as much as possible. There is.

The perspective view from the bottom face side which shows the core made from a magnetic body used for this invention. The perspective view from the upper surface side which shows the chip antenna which concerns on this invention. The perspective view from the bottom face side which shows the chip antenna concerning the present invention. The perspective view which shows the board | substrate used for this invention. The perspective view which shows another embodiment of the board | substrate used for this invention. The assembly perspective view of the antenna module which concerns on this invention. The perspective view which shows the antenna module which concerns on this invention. The perspective view from the bottom face side which shows another embodiment of the chip antenna used for this invention. The perspective view which shows another embodiment of the board | substrate used for this invention. The bottom side perspective view which shows the core for conventional antenna modules. The assembly perspective view which shows the conventional antenna module.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, the shape of each figure referred in the following description is a conceptual diagram or a schematic diagram for explaining an official shape dimension, and a dimension ratio etc. do not necessarily correspond with an actual dimension ratio. That is, the present invention is not limited to the dimensional ratio in the drawings.

The manufacturing process of the chip antenna / antenna module according to the present invention includes a “core manufacturing process” for manufacturing a core, a “pattern manufacturing process” for obtaining a chip antenna by providing an antenna pattern on the core, and a “board for mounting a chip antenna” It is divided into a “preparation step” and a “module assembly step” in which the chip antenna and the substrate are combined to form an antenna module.

"Core manufacturing process"
First, magnetic powder such as ferrite (Ni—Zn, Mn—Zn), iron powder, green compact, Ni—Zn, and Mn—Zn is press-molded and fired to obtain the core 1 shown in FIG. The core 1 has a recess 3 on the bottom surface 2. The concave portion 3 is preferably molded and fired because it saves labor, but after the magnetic body is fired into a substantially rectangular parallelepiped, the concave portion 3 may be cut out or a plurality of parts may be manufactured and integrated. Since the concave portion 3 is released only on the bottom surface, the magnetic fields on the top surface and the side surface of the core are equalized, and signals can be transmitted and received evenly in all directions. It is preferable that the recessed part 3 is a required and sufficient size for accommodating the electronic component mentioned later. If the concave portion 3 is too wide in the plane direction, the antenna pattern on the bottom surface cannot be formed, and the area of the substrate connecting portion described later becomes small and the adhesive strength to the substrate decreases. If the recess 3 is made too deep, the amount of the magnetic material is reduced and the performance of the antenna is lowered. Note that the “substantially rectangular parallelepiped” includes minor shape changes such as chamfering with a C surface at corners and sides from a rectangular parallelepiped, and rounding with R.

"Pattern manufacturing process"
Next, as shown in FIGS. 2 and 3, the antenna pattern 4 and the substrate connecting portion 5 are provided directly on the surface of the obtained core 1. A conductive metal, particularly preferably a metal paste such as Ag, Ag + Pd, Ag + Pt, Au, or Cu is printed on the shape of the antenna pattern 4a on the upper surface 6 of the core 1 and dried. The antenna pattern 4 a is provided with its end portions 7 a, 7 b, 7 c, and 7 d on the side 9 that is a boundary with the side surface 8. The antenna pattern 4a printed on the upper surface 6 is a part of the loop antenna, and the number of laps is determined according to the required antenna performance, but is preferably set to one or more. Considering the provision on the bottom surface 2 of the core 1, it is preferably 2 to 5 turns.

It is preferable that the antenna pattern 4a does not enter the central portion when the upper surface is divided into nine equal parts in the vertical and horizontal directions. When the antenna pattern 4a enters the center portion, when manufacturing a substrate or product (final product) on which the chip antenna or antenna module of the present invention is mounted, the antenna pattern is obtained when the component is adsorbed by an adsorption type assembly machine (mounter). 4a may be damaged and the characteristics may be changed or the wire may be disconnected and become unusable. Further, even if the antenna pattern 4a is printed up to the center portion, it is too close to the central axis and therefore hardly contributes to the improvement of the L value. Therefore, it is preferable to avoid the central portion. Further, it is preferable to set the thickness of the antenna pattern 4a to 0.3 to 0.7 mm and the distance between the patterns to 0.1 to 0.4 mm because the L value can be improved without printing on the central portion.

Thereafter, the side surface antenna pattern 4b is printed from the end portions 7a, 7b, 7c, and 7d to the end portions 7e, 7f, 7g, and 7h on the side 10 that is the boundary with the bottom surface 2 and dried. Thereafter, the board connecting portion 5 and the antenna pattern 4c on the bottom surface are printed on the bottom surface 2 and dried. Substrate connecting portions are provided at the four corners of the bottom surface 2. The antenna pattern 4c extends from the end portions 7e, 7f, 7g, and 7h. The end portion 7e is connected to the terminal end 11 of the antenna pattern 4, and the end portion 7g is connected to the pattern of the starting end 12, and the end portion f and the end portion are connected. The part h is connected by bypassing the starting end 12 on the bottom surface 2 in a planar manner to form a bypass 13. By using the planar detour 13, the antenna pattern starting end 12, the loop including the detour 13, and the terminal end 11 are all provided directly on the surface of the magnetic material. After printing and drying on all three surfaces, the chip antenna 14 is obtained by firing and fixing to the surface of the core 1. In the present invention, the antenna pattern is interpreted with the end on the outer peripheral side as the end and the end on the inner peripheral side as the start.

"Board preparation process"
Next, a substrate 21 shown in FIG. 4 for mounting the chip antenna 14 is prepared. The substrate 21 (21a) is larger than the core in plan view. The substrate 21 is connected to the component electrode (not shown) for mounting the electronic component 22 on the upper surface thereof, the core connection part for fixing the chip antenna, and the antenna pattern starting end 12 and terminal end 11 respectively. It has a starting end connecting portion 23 and a terminating end connecting portion 24. In addition, on the back and side surfaces, a signal electrode, a power supply electrode, a ground electrode, a fixing dummy electrode, and the like, which are used when mounted on a product (not shown), are appropriately provided depending on the application. The place where the electronic component 22 is mounted corresponds to the recess 3 of the core 1 near the center of the substrate 21. Further, the start end connection portion 23 and the end connection portion 24 are provided at positions corresponding to the start end 12 and the end end 11 provided on the bottom surface of the chip antenna 14, respectively. The core connection portion 25 is provided at a position corresponding to the substrate connection portion provided on the bottom surface of the chip antenna 14. Further, as shown in FIG. 5, when the substrate 21b having a slit 27 having a predetermined length from the side end face 26 is used, the substrate 21 is soldered to the module assembly process described later or the substrate 21b. At this time, the substrate 21b is not damaged by the deformation of the substrate due to heat of soldering, which is preferable.

"Module assembly process"
A cream solder (not shown) is placed on the start end connection portion 23, the end connection portion 24, and the core connection portion 25 of the substrate 21, and the start end 12, the end end 11, and the substrate connection portion 5 of the chip antenna 14 are respectively associated with them. As shown in FIG. 6, the electronic component 22 is placed so as to cover the lid, and heated to melt the cream solder and perform soldering. At this time, since the core connection portion 25 and the substrate connection portion 5 are automatically adjusted in position by the surface tension of the melted solder, a large deviation does not occur. Thus, the antenna module 28 shown in FIG. 7 is obtained.

The obtained antenna module 28 has received the radio wave because the magnetic core is enlarged to the maximum with respect to the installation area and the antenna pattern 4 is directly provided on the surface of the magnetic core 1. The signal sent to the antenna module 28 to efficiently convert and / or transmit the signal to the signal can be efficiently converted into a radio wave. In addition, since the electronic component 22 is provided inside the magnetic core 1, the core 1 absorbs noise generated by the electronic component 22, and particularly when the antenna module 28 is used on the transmission side, noise generated by the electronic component 22 is generated. The excellent effect of not leaking out of the antenna module 28 is exhibited.

Furthermore, characteristics when the chip antenna or the antenna module of the present invention is used for a product (final product) that requires an antenna function will be described. Since the chip antenna according to the present invention can store an electronic component in the recess, it is mounted so as to cover the electronic component mounted on the substrate of the final product without using the substrate used in the antenna module of the present invention. Can do. The antenna module houses electronic components therein. For this reason, signal processing electronic components and antennas are usually mounted separately and space is required, but in the present invention, by integrating the components, the characteristics of the antenna in the final product are degraded. It is possible to save space.

Further, the chip antenna and the antenna module are not broken by a small force like a ferrite sheet because a magnetic core has a predetermined rigidity. Therefore, when installing a chip antenna or antenna module in the final product, there is no need to make a special design such as securing the antenna installation surface on the case or the housing side or giving it a predetermined strength. Since the design of the outer shape can be freely performed, not only the chip antenna / antenna module but also the final product can be reduced in size and thickness while maintaining the performance of the antenna.

The features of the chip antenna and antenna module of the present invention will be further described. The induced electromotive force V generated in the antenna, that is, the voltage generated by the received radio wave is determined by the product of the horizontal sectional area S of the magnetic material and the magnetic flux Φ, V = S × Φ, and the V and L values are proportional. There is a relationship. When an antenna is formed by winding a conductive wire around a core as in the prior art, it is necessary to secure a space for winding by reducing the horizontal cross-sectional area of the core by the amount of the conductive wire, so that the induced electromotive force is lowered. That is, it cannot be efficiently converted from an electric wave to an electric signal. However, in the present invention, since the antenna pattern is directly printed on the upper surface of the core, the above-described space is not necessary, and the horizontal cross-sectional area of the magnetic body with respect to the installation area can be increased. Thereby, since the horizontal cross-sectional area with respect to the volume and installation area of a magnetic body becomes large, L value can be improved.

Also, according to Bio-Savart's law, the magnetic flux density B is inversely proportional to the distance, and decreases with increasing distance. The magnetic flux Φ described above is determined by the product of the magnetic flux density B and the horizontal sectional area S of the magnetic material, Φ = B × S. In conventional conductors and cores, an insulation coating with a thickness of several μm exists between the conductors of the conductors and the core, or floats near the corners, resulting in a distance between the conductor part and the magnetic body. The magnetic flux density was small. However, in the present invention, since the printing is performed directly on the core, the distance between the conductor portion and the magnetic material becomes zero and does not occur at all. Since the magnetic material is in contact with the magnetic material at the portion where the magnetic flux density is maximized, when the chip antenna / antenna module is used as the transmitting side, the signal can be efficiently converted into magnetic flux / radio waves.

  As described above, the details of the present invention have been described with reference to examples. However, the present invention is shown only as specific embodiments of the present invention, and the effects of the invention are remarkably impaired based on the technical idea. It should be understood that some of the embodiments can be modified and implemented to a lesser extent. For example, (1) the antenna pattern can be etched after vapor deposition or sputtering instead of paste printing to produce a desired pattern. (2) The loop number of loops of the antenna pattern is adjusted to a decimal number such as 2.5 or 3.25, not an integer, and is extended from a side different from the starting end to the bottom side and connected to the substrate. (3) The shape of the core and the substrate can be made circular in plan view. (4) The number of rounds of the antenna provided in the core is increased, and as shown in FIG. 8, only the detour end portion 30 is provided on the bottom surface 2 of the core 1, and the corresponding substrate 21d as shown in FIG. The board-side detour 31 and the board-side detour end 32 are created. The detour end 30 and the board detour end 32 are soldered to complete the antenna pattern. At this time, the substrate side bypass 31 may be provided inside the substrate without being exposed on the surface of the substrate 21d. In addition, both the detour and the substrate side detour can be provided.

According to the present invention, the present invention can be widely used in the field of near field communication such as NFC antenna and Felica antenna.

1: Core 2: Bottom surface 3: Concave portions 4, 4a, 4b, 4c: Antenna pattern 5: Substrate connection portion 6: Upper surface 7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h: End portion 8: Side surface 9: Side 10: Side 11: End 12: Start 13: Detour 14: Chip antennas 21, 21a, 21b, 21d: Substrate 22: Electronic component 23: Start end connection 24: End connection 25: Core connection 26: Side end face 27: slit 28: antenna module 30: detour end 31: substrate side detour 32: substrate side detour end 41: opening 42: core 43: conductor 44: chip antenna 45: substrate 46: electronic component 47: Antenna module

Claims (15)

A core made of a columnar magnetic body, placed on a substrate on which an electronic component is mounted on the top surface via a bottom surface, and an antenna pattern directly provided on the surface of the core,
The core is provided with a concave portion opened only on the bottom surface side to accommodate electronic components, and the antenna pattern has both a start end and a terminal end on the bottom surface of the core, and the antenna pattern is 1 A chip antenna, wherein the chip antenna is wound more than a circumference and has a detour in the middle of the antenna pattern that detours inward from the starting end on the bottom surface of the core .   The chip antenna according to claim 1, wherein the antenna pattern is provided from the top surface of the core through the side surface to the bottom surface.   2. The chip antenna according to claim 1, wherein the detour is provided directly on a bottom surface of the core, and the start end is planarly detoured in the inner direction of the core on the bottom surface. Among the antenna pattern, the portion provided on the upper surface of the core, among the 9 equal parts with the upper surface divided into three equal parts in the vertical and horizontal directions, according to claim 1 in which only provided in the portion excluding the central portion Chip antenna.   The chip antenna according to claim 1, wherein the antenna pattern has a width of 0.3 to 0.7 mm.   The chip antenna according to claim 1, wherein the antenna patterns are provided at intervals of 0.1 to 0.4 mm between adjacent patterns on the upper surface of the core. A substrate, an electronic component placed on the top surface of the substrate, a magnetic core placed on the top surface of the substrate via a bottom surface, and an antenna pattern directly provided on the surface of the core ,
The core is provided with a concave portion opened only on the bottom surface side, and the electronic component is accommodated in the concave portion, and the antenna pattern has both a start end and a terminal end on the bottom surface of the core, The antenna module , wherein the antenna pattern is wound one or more times, and has a detour that detours inward from the starting end on the bottom surface of the core in the middle of the antenna pattern . The antenna module according to claim 7 , wherein the antenna pattern is provided from the top surface of the core through the side surface to the bottom surface. The antenna module according to claim 7 , wherein the bypass is directly provided on a bottom surface of the core, and the start end is planarly bypassed in the inner direction of the core on the bottom surface. The antenna module according to claim 7 , wherein the bypass is provided on the substrate. Among the antenna pattern, the portion provided on the upper surface of the core, among the 9 equal parts with the upper surface divided into three equal parts in the vertical and horizontal directions, according to claim 7, only provided on a portion excluding the central portion Antenna module. The antenna module according to claim 7 , wherein a thickness of the antenna pattern is 0.3 to 0.7 mm. The antenna module according to claim 7 , wherein an interval between adjacent patterns of the antenna pattern is 0.1 to 0.4 mm. The antenna module according to claim 7 , wherein the substrate has a slit having a predetermined length from a side end surface thereof. The antenna module according to claim 7 , wherein a gap is provided between the substrate and the core.

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