JP2008072559A - Antenna system and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna system, manufacturing method thereof and compound electronic component in which a radiation electrode and a ground electrode can be highly accurately positioned. <P>SOLUTION: A radiation electrode 30 and a ground electrode 32 which is disposed in counter to the radiation electrode 30, are integrally molded by a mold resin. When seeing through the radiation electrode 30 and the ground electrode 32 in a normal direction, the radiation electrode 30 has an area 32s that does not overlap with the ground electrode 32, and the ground electrode 32 has an area 30s that does not overlap with the radiation electrode 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  Conventionally, an antenna device for adding a communication function to an IC card or the like has been proposed.

  For example, in the conventional example 1 shown in the cross-sectional view of FIG. 1, the ground pattern (ground electrode) 111 pasted on one surface of the printed circuit board 110 and the other surface of the printed circuit board 110 are patterned, and various circuit elements are attached. Circuit pattern 112, a mold case 120 which is a resin casing covering the other surface side of the printed circuit board 110, and an antenna pattern (radiation electrode) which is a planar antenna provided by transfer molding in the vicinity of the outer surface side of the mold case 120 140). The mold case 120 has a hole 121 for connecting the antenna pattern 140 and the circuit pattern 112 with a lead pin or the like (see, for example, Patent Document 1).

2 has an antenna pattern (radiating electrode) 212 serving as an antenna element formed on one surface of the low-temperature fired ceramic multilayer substrate 210. The antenna unit 232 shown in the perspective view of FIG. An antenna element feed point 214 is electrically connected to a hybrid IC unit 226 including a high frequency amplification IC chip 222, a chip capacitor 224, and the like via a conductor of a via hole 216, an internal conductor 218, a bonding wire 220, and the like. . An internal conductor (ground electrode) 228 for shielding is provided between the antenna pattern 212 and the hybrid IC portion 226. Pins 230 for mechanical and electrical connection to a motherboard (not shown) are brazed to the ceramic multilayer substrate 210 (see, for example, Patent Document 2).
JP-A-9-199940 Japanese Patent Laid-Open No. 5-160635

  The conventional example 1 shown in FIG. 1 has the following problems.

  It is necessary to insert a power supply lead pin or the like into the hole 121 of the mold case 120, and the process is complicated and the manufacturing cost is high.

  It is necessary to provide an electrical contact with the power supply lead pin on the printed circuit board 110 without fail. Since the area occupied by the power supply lead pins and the hole 121 of the mold case 120 is inevitably generated on the printed circuit board 110, the layout flexibility of the surface-mounted electronic components such as the chip product 113 and the transistor 114 is low, and the size is reduced. It is also difficult. If priority is given to the layout of surface-mounted electronic components such as the chip product 113 and the transistor 114, the layout of the antenna pattern is restricted, and it can be said that the degree of freedom of the structure is generally low.

  Since the distance L between the antenna pattern 140 and the earth pattern 111 is large, the electric capacity between both electrodes is small. When it is desired to increase the electric capacity in order to obtain a desired resonance frequency, it is necessary to increase the size of the antenna pattern 140, and it is difficult to reduce the size of the mold case 120.

  Since the assembly of the mold case 120 and the printed board 110 is a fitting type (positioning method by placing the printed board 110 against the resin mold case 120), the distance L between the antenna pattern 140 and the ground pattern 111 varies greatly. . The electric capacity between the electrodes 111 and 140 varies, and the antenna characteristics are also deteriorated such that the resonance frequency varies and the antenna gain decreases due to deviation from the designed and optimized electric capacity. Further, since the positioning is performed with the resin mold case 120, the planar positioning of the printed circuit board 110 and the antenna pattern 140 is poor. For this reason, the position of the feeding point varies, and the antenna characteristics also deteriorate such that the resonance frequency varies and the antenna gain decreases due to deviation from the designed and optimized electric capacity.

  The assembly of the mold case 120 and the printed circuit board 110 is a fitting type, and when a mechanical load such as vibration, impact, torsion or the like is applied, there is a risk that both will come off and the reliability is low. In addition, when an environmental load such as thermal shock is applied, the fitting is loosened due to the thermal expansion and contraction of both, and there is a risk that it will come off and the reliability is low.

  The assembly of the mold case 120 and the printed circuit board 110 is a fitting type, and it is necessary to handle the printed circuit boards one by one. Therefore, the process is complicated, the mass productivity is low, and the manufacturing cost is high as compared with the case where the assembly with the mold case is performed in a collective substrate state in which a plurality of pieces are assembled together.

  The ground pattern 111 needs to be provided on one surface of the printed circuit board 110, and a surface-mount type electronic component such as the chip product 113 or the transistor 114 cannot be mounted, or the area on which the surface mount electronic component can be mounted is small. Therefore, the area utilization efficiency of the printed circuit board 110 is low, and it is difficult to reduce the size.

  On the other hand, the conventional example 2 shown in FIG. 2 has the following problems.

  An antenna pattern 212 is formed on one surface of the low-temperature fired ceramic multilayer substrate 210. For this reason, it is difficult to downsize the surface-mounted electronic component because it cannot be mounted on both sides.

  It is necessary to braze pins 230 for mechanical and electrical connection to the motherboard. Such work is complicated and mass productivity is poor.

  In view of such circumstances, the present invention intends to provide an antenna device, a manufacturing method thereof, and a composite electronic component that can position a radiation electrode and a ground electrode with high accuracy.

  In order to solve the above problems, the present invention provides an antenna device configured as follows.

  The antenna device is of a type in which a radiation electrode and a ground electrode arranged to face the radiation electrode are integrally formed of a mold resin. When the radiation electrode and the ground electrode are seen through in the normal direction, the radiation electrode has a region that does not overlap the ground electrode (hereinafter referred to as “first region”), and the ground electrode is the radiation. It has a region that does not overlap with the electrode (hereinafter referred to as “second region”).

  In the above configuration, the first region of the radiation electrode and the second region of the ground electrode can be provided by forming a hole, a notch, a projecting piece, or the like in the radiation electrode or the ground electrode.

  According to the above configuration, when integrally molding with the mold resin, the radiating electrode and the ground electrode are respectively molded using the first and second regions that do not overlap the other when seen through in the normal direction. Can be positioned with high accuracy.

  Preferably, the radiation electrode is formed with a first opening penetrating in the normal direction in a portion overlapping the second region of the ground electrode when the radiation electrode and the ground electrode are seen through in the normal direction. Has been. The ground electrode has a second opening penetrating in the normal direction in a portion overlapping the first region of the radiation electrode when the radiation electrode and the ground electrode are seen through in the normal direction. . The mold resin has first and second hollow portions that pass through the first and second openings, respectively.

  In this case, when the mold resin is integrally molded, the support can be inserted into the first and second openings, and the radiation electrode and the ground electrode can be positioned with respect to the mold. In the mold resin, first and second hollow portions that pass through the first and second openings, respectively, are formed in the portion where the support is disposed.

  Preferably, the power supply device further includes a power supply electrode disposed to face the radiation electrode.

  In this case, a signal from the feeding electrode to the radiation electrode can be supplied. Note that the lead-out portion of the power supply electrode and the lead-out portion of the ground electrode are preferably drawn from different sides. This is because the currents flowing through the lead portions may interfere with each other if they are drawn from the same side.

  Preferably, the power supply electrode is disposed on the same plane as the ground electrode.

  In this case, the power supply electrode and the ground electrode can be formed from the same plate member, and the configuration is simplified.

  Preferably, when the radiation electrode and the feeding electrode are seen through in a normal direction, the radiation electrode and the feeding electrode overlap in a whole area inside a boundary of the region where the radiation electrode and the feeding electrode overlap. Yes.

  In this case, since no opening is formed in the power supply electrode at the portion overlapping the radiation electrode, the flow of the supply signal is stabilized. This is because if the power supply electrode that supplies a signal to the radiation electrode has an opening in a portion that overlaps the radiation electrode, the flow of the supply signal becomes difficult to stabilize.

  Preferably, the maximum dimension of the second opening of the ground electrode is ¼ wavelength or less at a use frequency.

  When the maximum dimension of the second opening formed in the ground electrode (for example, the diameter in the case of a round hole, the width in the case of a notch) is equal to or less than ¼ wavelength at the use frequency, the use frequency or the use thereof Since electromagnetic waves in a frequency band higher than the frequency do not enter the opposite side from the radiation electrode side via the second opening of the ground electrode, the surface mount type electronic component disposed on the opposite side of the radiation electrode with respect to the ground electrode, etc. On the other hand, it is less likely to have an adverse effect.

  Preferably, the ground electrode is connected to a lead portion for connecting the ground electrode to a ground terminal, and the second opening is formed at a position away from the lead portion.

  In this case, the second opening of the ground electrode is formed at a position away from the lead portion so as not to hinder the flow of current through the lead portion. This is because when the second opening is adjacent to the lead portion, the flow of current through the lead portion is hindered.

  Preferably, the periphery of the radiation electrode is covered with the mold resin along an outer edge, and a central portion is exposed from the mold resin.

  In this case, the periphery of the radiation electrode can be fixed with a mold resin. Since the central portion of the radiation electrode is exposed from the mold resin, transmission and reception can be performed efficiently.

  Moreover, in order to solve the said subject, this invention provides the manufacturing method of the antenna device comprised as follows.

  The method for manufacturing an antenna device is a method for manufacturing an antenna device by integrally molding a radiation electrode and a ground electrode disposed to face the radiation electrode with a mold resin. In the method of manufacturing an antenna device, (1) the first opening that penetrates in the normal direction is formed in the radiation electrode, and the second opening that penetrates in the normal direction is formed in the ground electrode. And (2) supporting a portion other than the second opening of the ground electrode through the first opening of the radiation electrode, and the second step of the ground electrode. A second step of integrally molding the radiation electrode and the ground electrode using the molding resin in a state in which a portion other than the first opening of the radiation electrode is supported through the opening of .

  According to the above method, it is possible to integrally mold using the molding resin in a state where the radiation electrode and the ground electrode are positioned with high accuracy using the first and second openings.

  Moreover, in order to solve the said subject, this invention provides the composite electronic component comprised as follows.

  In the composite electronic component, (a) a wiring board on which a surface mount type electronic component is mounted, (b) a radiation electrode, and a ground electrode arranged to face the radiation electrode are integrally formed with a mold resin, And a case with an antenna which is bonded to the wiring board so as to cover the surface-mounted electronic component on the side opposite to the radiation electrode with respect to the ground electrode. The case with an antenna is provided with a first opening in the radiation electrode and a second opening in the ground electrode, and when the radiation electrode and the ground electrode are seen through in a normal direction, The first opening overlaps a portion of the ground electrode other than the second opening, and the second opening overlaps a portion of the radiation electrode other than the first opening.

  According to the above configuration, the case with the antenna can be integrally molded using the mold resin in a state where the radiation electrode and the ground electrode are positioned with high accuracy using the first and second openings.

  According to the present invention, the radiation electrode and the ground electrode can be positioned with high accuracy. Since the distance between the electrodes is stabilized, the capacitance between the electrodes is stabilized, and the antenna characteristics are stabilized and improved. Moreover, since the positional deviation with respect to a circuit board electrode is small, it is excellent in mounting property and has high joining reliability.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  3 is a cross-sectional view schematically showing a basic configuration of a mold case (hereinafter simply referred to as “case”) 12 which is a case with an antenna.

  In the case 12, the radiation electrode 30, the ground electrode 32, the power supply electrode 34, and the like are molded integrally with the case body 20.

  FIG. 4 is a plan view taken along line AA of FIG. In FIG. 4, a portion exposed to the outside of the radiation electrode 30 is hatched. As shown in FIGS. 3 and 4, a recess 21 is formed on the upper surface side of the case body 20, and the central portion of the radiation electrode 30 is exposed to the outside from the recess 21. The periphery of the radiation electrode 30 is covered with the resin of the case body 20 along the outer edge thereof, and is fixed to the case body 20.

  As shown in FIG. 4, a lead portion 31 is connected to the radiation electrode 30. The lead-out portion 31 may be an external terminal that is exposed at the distal end side extending outside the case body 20 and is electrically connected to another device if necessary.

  FIG. 5 is a cross-sectional view taken along line BB in FIG. As shown in FIGS. 3 and 5, the ground electrode 32 and the feeding electrode 34 are spaced apart from the radiation electrode 30 by a predetermined distance so as to face the radiation electrode 30 and be parallel to the radiation electrode 30. Is placed inside. The ground electrode 32 and the power supply electrode 34 are formed of the same plate member and are arranged on the same plane.

  As shown in FIG. 5, lead portions 33 and 35 are connected to the ground electrode 32 and the power feeding electrode 34, respectively. The lead portions 33 and 35 may be exposed as external terminals that extend outward from the case body 20 and are electrically connected to other devices if necessary.

  The lead-out portion 33 of the ground electrode 32 and the lead-out portion 35 of the power supply electrode 34 are each drawn from opposite sides. The lead portion 33 of the ground electrode 32 and the lead portion 35 of the power supply electrode 34 are preferably drawn from different sides. This is because currents flowing through the lead portions 33 and 35 may interfere with each other if they are drawn from the same side.

  The diameters of the through holes 32a and 32b formed in the ground electrode 32 are set to ¼ wavelength or less at the operating frequency. Accordingly, electromagnetic waves in the use frequency or in a higher frequency band than the use frequency do not enter the opposite side from the radiation electrode 30 side through the through holes 32 s and 32 t formed between the ground electrode 32 and the radiation electrode 30. As will be described later, the surface mount type electronic components 15 and 16 (see FIG. 6) disposed on the opposite side of the radiation electrode 30 with respect to the ground electrode 32 are less likely to be adversely affected.

  The through hole 32 b of the ground electrode 32 is formed at a position away from the lead portion 33 connected to the ground electrode 32. That is, the through hole 32 b is formed at a position away from the lead portion 33 so as not to hinder the flow of current through the lead portion 33. This is because if an opening is formed adjacent to the lead portion 33, the flow of current through the lead portion is hindered.

  The feeding electrode 34 has no opening formed in a region overlapping the radiation electrode 30 when viewed from the normal direction. Therefore, the flow of the supply signal is stabilized. This is because if the opening is formed, the flow of the supply signal becomes difficult to stabilize.

  Terminal portions 32 x and 34 x are connected to the ground electrode 32 and the power feeding electrode 34. As shown in FIG. 3, the terminal portions 32 x and 34 x are bent into a substantially L-shaped cross section, and connection terminals 36 and 38 that are exposed on the bottom surface of the case main body 20 are formed by respective tip portions.

  As shown in the cross-sectional view of FIG. 7 corresponding to the cross-section along the line CC in FIGS. 4 and 5, the case 12 has support pins 52, 54; 62, protruding from the upper mold 50 and the lower mold 60, respectively. In a state where the electrodes 30, 32, 34 are sandwiched and held between the tips of 64, the molten resin is injected into the cavity 70 between the upper mold 50 and the lower mold 60 at a high pressure, Molded integrally with the electrodes 30, 32, and 34.

  As shown in FIGS. 4 and 5, the electrodes 30, 32, 34 are formed with through holes 30a, 30b; 32a, 32b through which the support pins 52, 54; 62, 64 are inserted. Specifically, a support pin 52 protruding from the upper mold 50 is inserted into the through holes 30a and 30b of the electrode 30 shown in FIG. 4, and the lower end of the support pin 52 and the upper end of the support pin 62 protruding from the lower mold, Between the electrodes 32 and 34 shown in FIG. 5 (regions that do not overlap the electrodes 30 of the electrodes 32 and 34 when the electrodes 30, 32 and 34 are seen through in the normal direction) 30 s and 30 t Is pinched. 5 is inserted into the through holes 32a and 32b of the ground electrode 32, and the upper end of the support pin 64 and the lower end of the support pin 54 protruding from the upper die are inserted. 4, the portions indicated by broken lines of the electrode 30 shown in FIG. 4 (regions that do not overlap the electrode 32 of the electrode 30 when the electrodes 30, 32, and 34 are seen through in the normal direction) are sandwiched between 32 s and 32 t. .

  Since the electrodes 30, 32, 34 are sandwiched and held by the support pins 52, 54; 62, 64, the electrode position shift due to the pressure of the molten resin does not occur. Therefore, the electrodes 30, 32, 34 can be positioned with high accuracy with respect to the case body 20.

  After the molding, the support pins 52, 54; 62, 64 are removed from the work at the same time as the work is released. Since the resin does not reach the place where the support pins 52, 54; 62, 64 were present during molding, the part where the support pins 52, 54; 62, 64 were formed during molding was indented. Thus, a hollow hole is formed.

  As shown in the sectional view of FIG. 6, the connection terminals 36 and 38 of the case 12 are connected to the one main surface 14 a of the substrate 14 via the bonding material 13, so that the case 12 and the substrate 14 are bonded. The composite electronic component 10 is formed. The bonding material 13 is solder, a conductive adhesive, or the like supplied by a method such as printing, dispensing, or transfer.

  The substrate 14 is a printed wiring board, a flexible printed wiring board, an alumina substrate, an LTCC (Low Temperature Co-fired Ceramic) substrate, or the like. On the substrate 14, surface mount type electronic components 15 and 16 are mounted.

  That is, the bare IC 15 is die-bonded to the one main surface 14a of the substrate 14 or wire-bonded by a wire 17 such as Au, Al, or Cu. Surface mounted electronic components other than the bare IC 15 may be mounted. A sealing resin 18 is applied to the bare IC 15 to protect the bare IC 15.

  A surface-mounted electronic component 16 is also mounted on the other main surface 14 b of the substrate 14.

  The case 12 may be bonded to any one of the surfaces 14 a and 14 b of the substrate 14, but in FIG. 6, the surface mount type is bonded to the one main surface 14 a of the substrate 14 and mounted on the one main surface 14 a of the substrate 14. The electronic component 15 is covered. The surface 14b on the side where the case 12 of the substrate 14 is not joined may be joined with a metal case or covered with a resin as necessary.

  The antenna device and the composite part described above have the following operations and effects.

  (1) No power supply lead pin as in the conventional example is required. There is no complicated process of inserting the power supply lead pin into the hole of the mold case. This is only a process of insert-molding the radiation electrode, the ground electrode, and the power feeding electrode with a mold resin, and there are fewer manufacturing processes and simpler than the conventional example. Manufacturing cost is reduced.

  (2) Since no power supply lead pins are required, there is no area occupied by the power supply lead pins or the mold case on the circuit board. The layout flexibility of surface mount electronic components is high. The antenna also has a radiation electrode, a ground electrode, and a feeding electrode all contained in a mold case, so that it is functionally independent from the circuit board and has a high degree of freedom in layout. The structure of the present invention generally has a high degree of structural freedom.

  (3) Since the ground electrode is housed in the mold case and the distance between the radiation electrode and the ground electrode can be reduced, the electric capacity between both electrodes can be increased. When antennas are designed at the same resonance frequency, the electrode size can be reduced as compared with the conventional example. The mold case can be downsized.

  (4) Since at least one of the radiation electrode, the ground electrode, and the power feeding electrode is supported by a support pin provided in the mold and positioned with high accuracy, the capacitance between both electrodes is stabilized. Accordingly, the antenna characteristics are stabilized and improved. In addition, the positioning of the radiation electrode, the ground electrode, and the feeding electrode in the planar direction can be performed with higher accuracy than the conventional example for the above reason, so that the antenna characteristics are stabilized and improved.

  (5) Since the assembly of the mold case and the circuit board is a surface mounting structure, both can be joined with a joining material such as solder, and the joining strength is strong. High reliability can be achieved even for mechanical loads such as vibration, impact and torsion.

  (6) Even if the member is thermally expanded and contracted due to an environmental load such as thermal shock, thermal stress is absorbed by the spring property of each electrode terminal exposed to the circuit board side by the mold case, and high reliability of the joint can be realized. .

  (7) Since the mold case can be surface-mounted on the circuit board, assembly can be handled by the assembled circuit board. The manufacturing process is simpler and the tact time can be shortened than the conventional example. Excellent mass production and low manufacturing cost.

  (8) There is no restriction of providing a ground pattern on one surface of the circuit board. Since surface-mounted electronic components can be mounted on both sides of the circuit board, the area utilization efficiency of the printed circuit board is high and the size can be reduced.

  The present invention is not limited to the above-described embodiment, and can be implemented with various modifications.

  For example, the shape of the through hole formed in the electrode is arbitrary, and may be a polygon or the like. A gap may be formed between the through hole and the support pin.

  Furthermore, an appropriate shape portion (first region, second region) such as a notch or a protruding piece may be provided in the radiation electrode or the ground electrode instead of the through hole, and may be sandwiched by the support pins.

It is sectional drawing of an antenna device. (Conventional example 1) It is sectional drawing of an antenna device. (Conventional example 2) It is sectional drawing which shows the basic composition of an antenna device. (Example) It is a top view of an antenna device. (Example) It is sectional drawing of an antenna device. (Example) It is sectional drawing of the composite electronic component provided with the antenna apparatus. (Example) It is sectional drawing of an antenna device and a metal mold | die. (Example)

Explanation of symbols

10 Composite electronic parts 12 Case (antenna device)
14 Board (wiring board)
30 Radiation electrode 30a, 30b Through hole (first opening)
32 Ground electrode 32a, 32b Through hole (second opening)
34 Feeding electrode

Claims (10)

An antenna device in which a radiation electrode and a ground electrode arranged to face the radiation electrode are integrally formed of a mold resin,
When the radiation electrode and the ground electrode are seen through in the normal direction, the radiation electrode has a first region that is a region that does not overlap the ground electrode, and the ground electrode is a region that does not overlap the radiation electrode. An antenna device having a second region. The radiation electrode has a first opening penetrating in the normal direction in a portion overlapping the second region of the ground electrode when the radiation electrode and the ground electrode are seen through in the normal direction.
The ground electrode has a second opening penetrating in the normal direction in a portion overlapping the first region of the radiation electrode when the radiation electrode and the ground electrode are seen through in the normal direction.
2. The antenna device according to claim 1, wherein the mold resin has first and second hollow portions that respectively pass through the first and second openings. 3.   The antenna device according to claim 1, further comprising a feeding electrode disposed to face the radiation electrode.   The antenna device according to claim 3, wherein the feeding electrode is arranged on the same plane as the ground electrode.   When the radiation electrode and the feed electrode are seen through in the normal direction, the radiation electrode and the feed electrode overlap each other in the entire region inside the boundary of the region where the radiation electrode and the feed electrode overlap. The antenna device according to claim 3 or 4, wherein the antenna device is characterized.   6. The antenna device according to claim 1, wherein a maximum dimension of the second opening of the ground electrode is equal to or less than ¼ wavelength at a use frequency. The ground electrode is
A lead portion for connecting the ground electrode to a ground terminal is connected,
The antenna device according to claim 1, wherein the second opening is formed at a position away from the drawer.   The antenna device according to any one of claims 1 to 7, wherein the radiation electrode is covered with the mold resin along an outer edge, and a central portion is exposed from the mold resin. . A method for manufacturing an antenna device, wherein a radiation electrode and a ground electrode arranged opposite to the radiation electrode are integrally molded with a mold resin,
Forming a first opening penetrating in the normal direction in the radiation electrode, and forming the second opening penetrating in the normal direction in the ground electrode;
Supporting a portion of the ground electrode other than the second opening through the first opening of the radiation electrode and out of the radiation electrode through the second opening of the ground electrode A second step of integrally molding the radiation electrode and the ground electrode using the mold resin in a state in which a portion other than the first opening is supported;
A method for manufacturing an antenna device, comprising: A wiring board on which surface-mounted electronic components are mounted;
A radiating electrode and a ground electrode arranged opposite to the radiating electrode are integrally molded with a molding resin, and the wiring is arranged such that the opposite side of the ground electrode from the radiating electrode covers the surface-mounted electronic component A case with an antenna joined to a substrate;
With
The case with the antenna is
When the radiation electrode is provided with a first opening, and the ground electrode is provided with a second opening, and when the radiation electrode and the ground electrode are seen through in a normal direction, the first opening is provided. Is a part of the ground electrode other than the second opening, and the second opening overlaps a part of the radiation electrode other than the first opening.

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