JP3884281B2 - Small antenna and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a small antenna used for, for example, a mobile phone, a portable information terminal, a wireless LAN (local area network), and the like, and a manufacturing method thereof.
[0002]
[Prior art]
Antennas used for mobile phones and the like are required to be miniaturized, and various small antennas have been proposed.
[0003]
As the above-mentioned small antenna, a small antenna in which a meander-shaped antenna conductor is embedded in a dielectric chip is known (for example, see Japanese Patent Application Laid-Open No. 9-55618). This small antenna has a structure in which three dielectric layers are stacked. A meander-shaped antenna conductor is formed on the surface of the dielectric layer located at the center by means of printing, vapor deposition, plating or the like. Thereafter, three dielectric layers are laminated so that the dielectric layer on which the antenna conductor is formed is sandwiched between other dielectric layers. Thereby, a small antenna is formed.
[0004]
[Problems to be solved by the invention]
As described above, the conventional antenna has a problem that its manufacturing process is complicated and the cost becomes high.
[0005]
The objective of this invention is providing the small antenna which can aim at the reduction of cost, and its manufacturing method.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention has taken the following measures.
[0007]
The small antenna according to the first aspect of the present invention is: A meander-shaped planar antenna conductor, a first resin portion formed between the antenna conductor conductors by resin molding, with a part of the antenna conductor sandwiched between the mating surfaces of the first mold, and the first A second resin part formed so as to cover the first resin part formed between the antenna conductor and the conductor by resin molding, sandwiching the resin part between the mating surfaces of the second mold, and The resin forming the first resin part is made of a material having higher fluidity at the time of molding than the resin forming the second resin part. It is characterized by that.
[0008]
A method for manufacturing a small antenna according to another aspect of the present invention includes sandwiching an antenna conductor between mating surfaces of a first mold, forming a first resin portion on the antenna conductor, and forming the first resin portion of the antenna conductor. A second resin part is formed on the antenna conductor by sandwiching it between the mating surfaces of the second mold. And the resin forming the first resin part has a higher fluidity during molding than the resin forming the second resin part. It is characterized by that.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
[0010]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the shape of the antenna conductor is not limited, but it is basically assumed that it is a meandering conductor.
[0011]
(First embodiment)
FIG. 1 is a diagram showing a molding state in each molding process of the small antenna according to the first embodiment of the present invention. FIG. 2 is a diagram illustrating a molding process of the small antenna according to the first embodiment.
[0012]
The small antenna according to the first embodiment is manufactured as follows.
[0013]
For example, as shown in FIG. 1A, an antenna conductor 11 formed in a meander shape is prepared. The length of the antenna conductor 11 is set to a quarter wavelength, for example. The antenna conductor 11 is preferably formed by punching from a metal plate or etching. The antenna conductor 11 may be formed by bending a wire.
[0014]
Primary molding is performed by a primary molding die 21 shown in FIG. The primary molding die 21 has an upper die 21a and a lower die 21b. A part of the antenna conductor 11, for example, an intermediate portion in the width direction of the meander is sandwiched and held by the upper mold 21a and the lower mold 21b. Between the upper mold 21a and the lower mold 21b, resin molding cavities 22 and 23 are formed at positions corresponding to both end portions of the held antenna conductor 11 in the width direction of the meander. Resin injection holes 24 and 25 communicating with the cavities 22 and 23 are formed in the upper die 21a.
[0015]
The primary molding of the antenna conductor 11 is performed as follows. An intermediate portion in the width direction of the meander of the antenna conductor 11 is sandwiched between the mating surfaces of the upper mold 21a and the lower mold 21b. Then, a molding resin that is a dielectric is injected into the cavities 22 and 23 from the resin injection holes 24 and 25. As the molding resin used in the primary molding, it is desirable to use a material having higher fluidity (for example, PPS (polyphenylene sulfide) or liquid crystal polymer in which the amount of the ceramic powder is small) than the resin in the secondary molding described later. By using a resin having high fluidity, the molding resin can be injected into the cavities 22 and 23 with a low pressure. Therefore, primary molding can be performed without impairing the meander shape of the antenna conductor 11. In addition, fluidity | liquidity can be compared with a melt flow rate (melt flow rate).
[0016]
FIG.1 (b) is a figure which shows the shape of the primary molded product obtained by primary molding. In the primary molded product, first resin portions 12 a and 12 b are formed at both end portions of the antenna conductor 11 in the width direction of the meander over the entire length in the pitch direction. A resin layer 13 having the same thickness as the antenna conductor 11 is formed at the center of the antenna conductor 11. The reason is as follows. Since the antenna conductor 11 has a meander shape, a gap is formed around the conductor even in the portion held by the primary molding die 21. As a result, the molding resin injected into the cavities 22 and 23 wraps around the gap at the center of the antenna conductor 11 to form the resin layer 13.
[0017]
As described above, when the antenna conductor 11 is primarily formed, the center portion of the antenna conductor 11 is formed between the upper mold 21a and the lower mold 21b. Thereby, the meander shape of the antenna conductor 11 can be integrated with the molding resin without being deformed.
[0018]
Next, secondary molding is performed on the primary molded product by using a secondary molding die 31 shown in FIG. The secondary molding die 31 has an upper die 31a and a lower die 31b. The first resin parts 12a and 12b of the primary molded product are sandwiched and held by the upper mold 31a and the lower mold 31b. The upper mold 31a and the lower mold 31b are formed with a resin molding cavity 32 at a position corresponding to the middle portion of the antenna conductor 11, that is, the resin layer 13. A resin injection hole 33 communicating with the cavity 32 is formed in the upper mold 31a. The upper and lower surfaces of the cavity 32 are formed so as to be flush with the first resin portions 12a and 12b.
[0019]
Secondary molding is performed as follows. The first resin parts 12a and 12b of the primary molded product are sandwiched between the mating surfaces of the upper mold 31a and the lower mold 31b. Next, a molding resin as a dielectric is injected into the cavity 32 from the resin injection hole 33. As the molding resin used in the secondary molding, a material having lower fluidity than the resin used in the primary molding can be used. The reason is as follows. In the primary molded product, both ends of the antenna conductor 11 are fixed by the first resin portions 12a and 12b. Therefore, even if a resin having lower fluidity than the resin used in the primary molding is used, the deformation of the antenna conductor 11 can be suppressed and the secondary molding can be performed.
[0020]
FIG.1 (c) is a figure which shows the shape of the secondary molded product (finished product) obtained by secondary molding. In the secondary molded product, the second resin layer 14 is formed at the intermediate portion between the first resin portions 12 a and 12 b formed at both ends of the antenna conductor 11. A dielectric chip is formed by the first resin portions 12 a and 12 b and the second resin portion 14. In this case, one end of the antenna conductor 11 protrudes from the second resin layer 14 and becomes the power supply terminal 15. The other end of the antenna conductor 11 is also provided so as to protrude from the first resin portion 12. The protruding end is used as a support terminal when the antenna is attached to the circuit board.
[0021]
The small antenna 10 is completed by primary molding and secondary molding. The first resin portions 12a and 12b and the second resin layer 14 are smoothly formed on the same surface by the molding process described above.
[0022]
According to the first embodiment, the antenna conductor 11 is primarily molded by sandwiching the central portion of the antenna conductor 11 between the mating surfaces of the upper mold 21a and the lower mold 21b. Thus, the first resin portions 12a and 12b can be formed while suppressing the deformation of the meander shape at both end portions of the meander width direction of the antenna conductor 11. At the time of secondary molding, both end portions of the antenna conductor 11 can be integrated and held by the first resin portions 12a and 12b. Therefore, secondary molding can be performed while preventing the antenna conductor 11 from being deformed. Furthermore, even if the secondary molding is performed using a resin having lower fluidity than the resin used during the primary molding, the deformation of the meander shape of the antenna conductor 11 is small. Generally, a high dielectric resin (for example, PPS mixed with a large amount of ceramics) has low fluidity, but even in such a case, deformation of the antenna conductor 11 during secondary molding can be suppressed.
[0023]
As described above, in the first embodiment, primary molding and secondary molding can be performed while suppressing deformation of the antenna conductor 11 from the initial shape. Therefore, it is possible to manufacture the small antenna 10 having good antenna characteristics and uniform quality. Moreover, since the small antenna 10 can be easily manufactured by resin processing using a mold, the cost can be reduced.
[0024]
Further, the upper surface and the lower surface of the first resin portions 12a and 12b are provided at the same position in the direction of the plane including the width direction and the pitch direction of the meander of the antenna conductor. Thereby, since 1st resin part 12a, 12b can be used for the clamp at the time of secondary shaping | molding, secondary shaping | molding can be performed without forming the member for pressing especially separately. In this case, it is not necessary to provide all the upper and lower surfaces of the first resin portions 12a and 12b symmetrically. If a part of the first resin parts 12a and 12b is in a corresponding position on the upper surface and the lower surface, the part can be used for the presser at the time of secondary molding.
[0025]
In the first embodiment, since the first resin portions are provided on both sides, there is an advantage that the primary molded product can be easily set in the secondary molding die 31.
[0026]
As shown in FIG. 3A, a pressing projection 12c is formed on the side of the first resin portions 12a and 12b during primary molding, and secondary molding is performed using the pressing projection 12c. Also good. If the presser protrusion 12c is cut after the secondary molding, the product shown in FIG. 3B is completed.
[0027]
In this embodiment, the meander pitch direction of the antenna conductor is set to one direction, but this pitch direction may be changed (the same applies to the following embodiments).
[0028]
(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0029]
FIG. 4 is a diagram showing a molding state in each molding step when manufacturing a small antenna according to the second embodiment of the present invention. FIG. 5 is a diagram showing a molding process in the second embodiment.
[0030]
The small antenna 10 according to the second embodiment of the present invention is configured as shown in FIG. That is, the first resin portion 12 is formed in the middle portion of the antenna conductor 11 in the width direction of the meander. Second resin layers 14 a and 14 b are formed on the other portions excluding the first resin portion 12, that is, both end portions in the width direction of the meander of the antenna conductor 11.
[0031]
When manufacturing the small antenna according to the second embodiment, a primary molding die 41 shown in FIG. 5A and a secondary molding die 51 shown in FIG. 5B are used.
[0032]
As shown in FIG. 5A, the primary molding die 41 includes an upper die 41a and a lower die 41b. Both ends of the antenna conductor 11 in the width direction of the meander are sandwiched by the upper mold 41a and the lower mold 41b. Then, a resin molding cavity 42 is formed in an intermediate portion between the upper die 41a and the lower die 41b. Further, a resin injection hole 43 communicating with the cavity 42 is formed in the upper mold 41a.
[0033]
The primary molding is performed as follows. An intermediate portion in the width direction of the meander of the antenna conductor 11 is sandwiched between the mating surfaces of the upper die 41a and the lower die 41b. Next, a molding resin is injected into the cavity 42 from the resin injection hole 43. As the molding resin used in the primary molding, it is desirable to use a material having high fluidity as in the case of the first embodiment. By using a resin having high fluidity as the molding resin, the molding resin can be injected into the cavity 42 with a low pressure. Therefore, the meandering deformation of the antenna conductor 11 can be further reduced.
[0034]
FIG.4 (b) is a figure which shows the shape of the primary molded product which performed the primary shaping | molding process. In the primary molded product, the first resin portion 12 is formed in the middle portion of the antenna conductor 11 in the width direction of the meander. In this case, one end of the antenna conductor 11 protrudes laterally from the first resin portion 12 to become a power supply terminal 15. In addition, resin layers 13 having the same thickness as the antenna conductor 11 are formed at both ends of the antenna conductor 11. The reason is as follows. Since the antenna conductor 11 has a meander shape, a gap is formed around the conductor at both end portions held by the primary molding die 41. Thereby, the resin layer 13 is formed by the molding resin injected into the cavity 42 wrapping around the gaps at both ends of the antenna conductor 11. The resin layer 13 is formed to the outside of both ends of the antenna conductor 11.
[0035]
As shown in FIG. 5B, the secondary molding die 51 holds the middle portion of the antenna conductor 11 in the width direction of the meander of the antenna conductor 11, that is, the first resin portion 12 portion, by the upper die 41 a and the lower die 41 b. . Resin molding cavities 52 a and 52 b are formed at both ends of the secondary molding die 51. The upper mold 51a has resin injection holes 53a and 53b communicating with the cavities 52a and 52b.
[0036]
Secondary molding of the antenna conductor 11 using the secondary molding die 51 is performed as follows. The first resin part 12 of the primary molded product is sandwiched between the mating surfaces of the upper mold 51a and the lower mold 51b. Next, molding resin is injected into the cavities 52a and 52b from the resin injection holes 53a and 53b. The molding resin used at the time of secondary molding can use a material having lower fluidity than the resin used at the time of primary molding as in the case of the first embodiment.
[0037]
FIG.4 (c) is a figure which shows the shape of the secondary molded product (finished product) which performed the secondary shaping | molding process. In the secondary molded product, second resin layers 14 a and 14 b are formed on both ends of the first resin portion 12 formed in the intermediate portion of the antenna conductor 11.
[0038]
The small antenna 10 is completed by the primary molding process and the secondary molding process. The first resin portion 12 and the second resin layers 14a and 14b are smoothly formed on the same surface by the molding process described above. Moreover, each molding resin 12a, 12b, 14 can be used as it is as the exterior of the small antenna 10.
[0039]
According to the second embodiment, primary molding and secondary molding can be performed while suppressing deformation of the antenna conductor 11 from the initial shape, as in the first embodiment. Therefore, it is possible to manufacture the small antenna 10 having good antenna characteristics and uniform quality. Moreover, since the small antenna 10 can be easily manufactured by resin processing using a mold, the cost can be reduced.
[0040]
(Third embodiment)
A third embodiment of the present invention will be described with reference to FIG. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0041]
FIG. 6 is a diagram showing a molding state in each molding step when manufacturing a small antenna according to the third embodiment of the present invention.
[0042]
In the small antenna 10 according to the third embodiment of the present invention, as in the first embodiment, the first resin portions 12a and 12b are formed at both ends of the meander width direction of the antenna conductor 11 during the primary molding. Yes. In the third embodiment, for example, disc-shaped bosses (projections) 61a to 61d are formed at four corners on both surfaces of the first resin portions 12a and 12b.
[0043]
At the time of secondary molding, the disk-shaped bosses 61a to 61d of the primary molded product are held by upper and lower molds. Then, the second resin layer 14 is formed on the entire surface of the antenna conductor 11 including the first resin portions 12a and 12b so as to be flush with the disk-shaped bosses 61a to 61d.
[0044]
According to the third embodiment, the same effect as in the first embodiment can be obtained. In addition, since the second resin layer 14 is formed by being bonded to the disk-like bosses 61a to 61d of the first resin portions 12a and 12b, an antenna having excellent strength can be provided. Furthermore, since the second resin layer 14 is formed on both sides of the antenna, an antenna having an excellent aesthetic appearance can be provided.
[0045]
(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIG. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0046]
FIG. 7A is a cross-sectional view showing a state during the primary molding of a small antenna according to the fourth embodiment of the present invention, and FIG. 7B is a top view of FIG. In the fourth embodiment, the first resin portion 12 is formed between each conductor of the antenna conductor 11 and on one surface during the primary molding of the antenna. In this case, the 1st resin part 12 is provided with the island-shaped part 12d formed partially as shown in FIG. The island-shaped portion 12d is a portion provided such that the resin flows through between the antenna conductors 11 with the interval between them. The shape of the island-shaped portion 12d is arbitrary as long as it straddles the antenna conductor 11, and any shape may be used as long as the initial shape of the antenna conductor 11 can be maintained.
[0047]
After the first resin portion 12 is formed on the antenna conductor 11, the second resin layer 14 is formed on both surfaces of the antenna during secondary molding. When the island-shaped portion 12d of the first resin portion 12 is formed on one surface of the antenna conductor 11, it is difficult to hold the antenna conductor during secondary molding. However, secondary molding can be performed using the secondary presser protrusion by providing a secondary presser protrusion as shown in FIG. 3A on the side of the first resin portion 12 during the primary molding. it can. The secondary presser protrusion is cut after completion of the secondary molding to complete the small antenna 10. Further, as shown in FIG. 8, by forming the island-like portion 12d of the first resin portion 12 so as to protrude from the front surface and the back surface, the island-like portion 12d can be used as a presser during secondary molding. .
[0048]
In the first to fourth embodiments, the case where the product is completed by two times of the primary molding and the secondary molding has been described. However, the product is further obtained by many times of molding such as tertiary and quaternary. Of course, it may be completed.
[0049]
According to each of the embodiments described above, since the dielectric is formed by resin molding of the antenna conductor a plurality of times, the antenna conductor can be molded while suppressing deformation from the initial shape. Therefore, it is possible to obtain a small antenna with good antenna characteristics and uniform quality. In addition, the small antenna can be manufactured at low cost with excellent mass productivity.
[0050]
(Fifth embodiment)
FIG. 9 is a diagram showing a molding state in each molding process of the small antenna according to the fifth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and detailed description is abbreviate | omitted.
[0051]
A small antenna 10 according to the fifth embodiment uses, for example, an antenna conductor 11 formed in a meander shape as shown in FIG. As shown in FIG. 10, the width L between the conductors is set wider than the conductor width S.
[0052]
A low dielectric material having a dielectric constant ε of about 2.0 to 4.5, such as PPS (polyphenylene sulfide) or a liquid crystal polymer, with the upper and lower surfaces of the antenna conductor 11 sandwiched between the upper and lower mating surfaces of the primary molding die As shown in FIG. 9B, the first resin part 12 is formed between the conductors of the antenna conductor 11 and along the outer periphery thereof. The first resin portion 12 is formed with the same thickness as the antenna conductor 11.
[0053]
The primary molded product is set in a secondary molding die and subjected to secondary molding. At the time of the secondary molding, a high dielectric material having a dielectric constant ε of about 6.0 to 20 is used, and the second resin layer is formed on both upper and lower surfaces of the first resin layer 12 as shown in FIG. 14 is formed. As the high dielectric material, for example, a material obtained by mixing ceramics with the PPS is used.
[0054]
(Sixth embodiment)
A sixth embodiment of the present invention will be described with reference to FIG. Note that in the sixth embodiment, identical symbols are assigned to parts identical to those in the first embodiment and detailed description thereof is omitted.
[0055]
FIG. 11 is a sectional view showing the configuration of a small antenna 10 according to the sixth embodiment of the present invention. In FIG. 11, the 2nd resin part 14 is formed in the square shape with the high dielectric material, for example. A meander-shaped antenna conductor 11 is disposed between the two second resin portions 14. A first resin portion 12 made of an adhesive having a low dielectric constant is formed between the conductors of the antenna conductor 11 and the outer periphery thereof. The two second resin parts 14 and the antenna conductor 11 are bonded via the first resin part 12. That is, the second resin portion 14 and the antenna conductor 11 are laminated and bonded together by an adhesive material that becomes the first resin portion 12 and are integrally configured.
[0056]
Also in the small antenna 10 in the sixth embodiment, as in the case of the fifth embodiment, the resonance frequency can be lowered and a wide frequency band can be obtained while downsizing.
[0057]
Note that a thin adhesive may remain between the second resin portion 14 and the antenna conductor 11.
(Prototype example)
An example in which the small antenna 10 according to the sixth embodiment is actually prototyped will be described. In this prototype, a high dielectric material having a dielectric constant ε of 7.8 is used as the second resin portion 14. An epoxy adhesive having a dielectric constant ε of 3.5 is used as the adhesive that becomes the first resin portion 12. Further, the antenna conductor 11 having the pattern shown in FIG.
[0058]
The actually manufactured small antenna 10 is a rectangular parallelepiped having a width of 4 mm, a length of 8 mm, and a thickness of 1 mm. Further, the antenna conductor 11 has a first meander part 31, a second meander part 32, and a wide part 33 as shown in FIG. The traveling directions of the meander conductors of the first meander part 31 and the second meander part 32 are different from each other as indicated by arrows 30a and 30b. In the example in this case, the first meander part 31 and the second meander part 32 are arranged so that the traveling directions of the first meander part 31 and the second meander part 32 are orthogonal to each other. A wide portion 33 formed in a substantially triangular shape is connected to the tip of the second meander portion 32.
[0059]
The first meander unit 31 is provided with two terminals 34 and 35. One terminal 34 is used as a power supply terminal. The other terminal 35 is not particularly used and has a monopole power feeding system. The width a of the first meander part 31 is 3.2 mm, the distance b from the first meander part 31 to the rear end of the wide part 33 is 3.8 mm, and the length c of the wide part 33 is 2. The width (maximum width) d of the rear end portion of the wide portion 33 is 3 mm. The maximum width d of the wide portion 33 is set to a value equal to the total width d of the first meander portion 31 and the second meander portion 32. The conductor width S of the antenna conductor 11 is 0.2 mm, and the width L between the conductors is 0.2 mm.
[0060]
Note that the antenna conductor 11 having the pattern shown in FIG. 12 can be used as an inverted F feeding method. That is, the terminal 34 provided in the first meander part 31 can be used as a ground terminal, and the other terminal 35 can be used as a power supply terminal.
[0061]
FIG. 13 is a diagram showing the frequency characteristics of the small antenna 10 shown in the prototype. In FIG. 13, the horizontal axis represents frequency (GHz) and the vertical axis represents VSWR (voltage standing wave ratio). As shown in the frequency characteristics of FIG. 13, the small antenna 10 has a center frequency at the point a of “2.805 GHz”, a point b at which the VSWR is “2”, and a frequency at the point c of “2.725 GHz”. It is “2.865 GHz” and its ratio band is 5%.
[0062]
FIG. 14 is a diagram for comparing characteristics with the small antenna 10 and showing frequency characteristics of the comparative small antenna. In FIG. 14, the horizontal axis is frequency (GHz), and the vertical axis is VSWR, as in FIG. The small antenna for comparison uses the antenna conductor 11 having the same pattern as the antenna conductor 11 used in the prototype example. The small antenna is a rectangular parallelepiped having a width of 4 mm, a length of 8 mm, and a thickness of 1 mm in which an antenna conductor is embedded in a dielectric chip made of only a high dielectric material having a dielectric constant ε of 7.8. Yes. As shown in the frequency characteristics of FIG. 14, the comparative small antenna has a center frequency at point a of “2.375 GHz”, a point b at which VSWR is “2”, and a frequency at point c of “2.347 GHz”. And “2.401 GHz”, and the ratio band is 2.3%.
[0063]
As is clear from the frequency characteristics shown in FIGS. 13 and 14, the small antenna 10 shown in the above prototype example has a wide frequency band that is twice or more that of the small antenna manufactured by the conventional method. Yes.
[0064]
(Seventh embodiment)
A seventh embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and detailed description is abbreviate | omitted.
[0065]
FIG. 15 is a diagram showing a molding state in each molding process of the small antenna 10 according to the seventh embodiment of the present invention. In the seventh embodiment, when the antenna conductor 11 shown in FIG. 15A is primarily formed of a low dielectric material, the first resin portion 12 is interposed between the conductors of the antenna conductor 11 as shown in FIG. Is formed. In addition, both ends of the first resin portion 12, that is, the portions along the both sides of the antenna conductor 11 in the width direction of the meander (parallel to the direction of travel of the meander) are projected to the upper surface and the lower surface, and the integrally molded portions 12f and 12g. Is formed.
[0066]
The secondary molding of the primary molded product is performed as follows. The integrally molded parts 12f and 12g of the first resin part 12 are sandwiched between the mating surfaces of the upper mold and the lower mold of the secondary mold. Next, secondary molding is performed using a high dielectric material. That is, as shown in FIG. 15C, the second resin portion 14 having the same height as the integrally molded portions 12 f and 12 g is formed on both surfaces of the first resin portion 12. In the seventh embodiment, unlike the first embodiment, the integrally formed portions 12f and 12g of the first resin portion 12 are formed as narrow as possible so that the antenna conductor 11 and the second resin portion 14 face each other. It is preferable that the area does not decrease so much.
[0067]
Even when the first resin portion 12 is provided with the integrally molded portions 12f and 12g as described above, the antenna characteristics equivalent to those of the first embodiment can be obtained.
[0068]
In the seventh embodiment, integrally molded portions 12 f and 12 g are provided in the first resin portion 12 so as to extend along both sides of the antenna conductor 11 in the width direction of the meander. Thereby, the integral molding parts 12f and 12g can be hold | maintained with the mating surface of the mold for secondary molding, and secondary molding can be performed. Therefore, secondary molding becomes easy. Further, the both sides of the meander width direction of the antenna conductor 11 can be more firmly held by the integrally molded portions 12f and 12g of the first resin portion 12. Therefore, secondary processing can be performed while the antenna conductor 11 is kept in the initial shape. As a result, the small antenna 10 with uniform quality can be manufactured easily and inexpensively. Further, in the small antenna 10, the integrally molded portions 12 f and 12 g are formed along the meander pitch direction of the antenna conductor 11. Therefore, at the time of primary molding, the resin can flow between the conductors via the integrally molded portions 12f and 12g. Therefore, the small antenna 10 according to the seventh embodiment has an advantage of easy primary molding.
[0069]
In the seventh embodiment, the second resin portion 14 is provided so as to be positioned between the integrally molded portions 12 f and 12 g of the first resin portion 12. In addition to this, for example, the second resin portion 14 may be provided so as to cover the integrally molded portions 12f and 12g of the first resin portion 12, for example.
[0070]
(Eighth embodiment)
An eighth embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and detailed description is abbreviate | omitted.
[0071]
FIG. 16 is a view showing a molding state in each molding process of the small antenna 10 according to the eighth embodiment of the present invention. In the eighth embodiment, when the antenna conductor 11 shown in FIG. 16 (a) is primarily formed of a low dielectric material, the first resin portion is provided between and around the antenna conductor 11 as shown in FIG. 16 (b). 12 is formed. Further, an integrally molded portion 12h is formed along the pitch direction at the middle portion of the first resin portion 12, that is, at the middle portion of the meander width direction of the antenna conductor 11.
[0072]
Secondary molding is performed as follows. The integrally molded portion 12h of the first resin portion 12 of the primary molded product is sandwiched between the mating surfaces of the upper mold and the lower mold of the secondary molding die. Next, secondary molding is performed using a high dielectric material. That is, as shown in FIG. 16C, the second resin portion 14 having the same height as the integrally molded portion 12 h is formed on both surfaces of the first resin portion 12. In addition, it is preferable to form the integrally molded portion 12h of the first resin portion 12 as narrow as possible so that the facing area between the antenna conductor 11 and the second resin portion 14 does not decrease so much.
[0073]
Even when the integrally molded portion 12h is provided in the middle portion of the first resin portion 12 along the pitch direction of the antenna conductor 11 as described above, the antenna characteristics equivalent to those of the first embodiment can be obtained. .
[0074]
In the eighth embodiment, by providing the integrally molded portion 12h at the intermediate portion of the first resin portion 12, the integrally molded portion 12h is held by the mating surface of the secondary molding die as in the seventh embodiment. Therefore, there is an advantage that secondary molding is easy.
[0075]
In the eighth embodiment, the second resin portion 14 is provided so that the second resin portion 14 is disposed on both sides of the integrally molded portion 12 h formed in the first resin portion 12.
[0076]
In addition, you may provide the 2nd resin part 14 so that the integral molding part 12h of the 1st resin part 12 may also be covered.
[0077]
(Ninth embodiment)
A ninth embodiment of the present invention will be described with reference to FIGS. In the ninth embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0078]
In the ninth embodiment, as shown in FIG. 18, the positioning protrusions 50 a to 50 d are also formed at the four corners of the first resin portion 12 at the same time when the primary molded product is molded. As shown in FIG. 19, the positioning protrusions 50a to 50d are formed at the time of the primary molding so that the primary molded product is reliably positioned in the secondary molding die. Specifically, the positioning protrusions 50 a to 50 d are formed at the same height as the cavity 52 formed in the secondary molding die 51. Further, the outer dimension of the primary molded product including the positioning projections 50a to 50d is formed to be the same as the outer dimension of the secondary molded product. Thus, a part of the primary molded product is in contact with each surface of the cavity 52 of the secondary molding die. The second resin portion 14 is formed in a gap between the first resin portion 12 and the inner surface of the cavity 52 of the secondary molding die. Further, the positions of the positioning protrusions 50 a to 50 d in the secondary molding die 51 are formed so as to substantially coincide with the four corners of the cavities 52 a and 52 b in the secondary molding die 51. preferable. In this embodiment, as shown in FIG. 19A, the three positioning protrusions 50b, 50c, and 50d are located at the corners of the cavity 52, but the remaining positioning protrusions 52a are slightly shifted from the corners. . The reason why the position of the positioning protrusion 50a is shifted is that the protrusion 50a is separated from the gate position of the primary molding die. Therefore, if the position of the gate is set to another position, the positioning protrusions 50a to 50d can be formed so as to coincide with the four corners of the cavities 52a and 52b.
[0079]
FIG. 20 is a diagram showing an overview of the small antenna 10 after the secondary molding. The outer surfaces of the positioning protrusions 50 a to 50 d of the first resin part 12 form the outer surface of the antenna together with the second resin part 14.
[0080]
As described above, the positioning projections 50a to 50d are formed at the time of primary molding, and the positioning projections 50a to 50d are fixed both vertically and horizontally so that the primary molded product does not move at the time of secondary molding. . Therefore, the second resin 14 is not formed unevenly, and the antenna conductor 11 is not exposed from the second resin 14.
(Tenth embodiment)
A tenth embodiment of the present invention will be described with reference to FIGS. In the tenth embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0081]
In each of the embodiments described above, in order to prevent deformation of the antenna conductor 11, in the primary molding, both ends in the width direction of the meander of the antenna conductor 11 as shown in FIG. In the state, the central portion of the antenna conductor 11 is filled with resin. However, even in this case, the conductor is slightly deformed by the flow of the resin during filling (see FIG. 21B).
[0082]
In order to solve this problem, in the tenth embodiment, as shown in FIG. 22, at the time of the primary molding, the antenna conductor 11 is placed on both ends in the width direction of the meander and both the central part are molds for primary molding. 21 to form a primary molded product. FIG. 23A shows a perspective view of the primary molded product thus formed. A cross-sectional view of the primary molded product is shown in FIG. A through hole 12a is formed in the central portion of the primary molded product.
[0083]
Then, as shown in FIG. 24A, the antenna conductor 11 protruding outside the first resin portion 12 is bent and subjected to secondary molding to complete the small antenna 10 as shown in FIG.
[0084]
FIG. 24A is a cross-sectional view of the small antenna 10 after the secondary molding. FIG. 24B is a top perspective view, and FIG. 24C is a back perspective view.
[0085]
In the small antenna 10, the middle portion of the meander-shaped antenna conductor 11 in the width direction is embedded in the first resin portion 12, leaving the central portion. Then, both sides in the width direction of the antenna conductor 11 are bent along the surface of the first resin portion 12. A central portion of the first resin portion 12 is a through hole 12a penetrating in the thickness direction. The second resin portion 14 fills the through portion 12 a and covers the side surface and the upper surface of the first resin portion 12.
[0086]
As described above, in the tenth embodiment, in addition to the both ends of the meander width direction of the antenna conductor 11 in the primary molding, the center portion is also held by the mold. Thereby, the antenna conductor 11 can endure the resin filling pressure. Therefore, it is possible to form a primary molded product with uniform quality while suppressing deformation from the initial state.
[0087]
(Eleventh embodiment)
An eleventh embodiment of the present invention will be described with reference to FIG. In the eleventh embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0088]
In each of the above embodiments, the antenna conductor 11 is sandwiched between the molds 21 and filled with the (first) resin. In this case, the molds 21 are pressed against each other with a considerably large force (for example, several tons) in order to prevent the molds 21 from being opened by the resin filling pressure. For this reason, there exists a possibility that the insert frame 11a may be crushed by the force which presses the insert frame 11a of the metal mold | die 21. FIG.
[0089]
Therefore, in the eleventh embodiment, the mold 21 is improved, and the insert frame 11a is pressed by a pressing member 55 urged by an elastic material such as a spring, for example, as shown in FIG. I did it. And resin is inject | poured in the metal mold | die 21 in the state which hold | suppressed the insert frame 11a as shown in FIG.25 (b). In this case, the portion pressed by the pressing member 55 is a portion surrounded by a chain double-dashed line in FIG. In the eleventh embodiment, since the insert frame 11a is not pressed so as to be crushed by a mold, but is pressed with a strength that can withstand the filling pressure of the resin, the deformation of the antenna conductor 11 during molding can be suppressed.
[0090]
As described above, for example, by forming the first resin portion 12 made of a low dielectric material between the conductors of the antenna conductor 11 formed in a meander shape, the frequency band can be maintained in a wide band state. Further, the second resin portion 14 made of a high dielectric material is formed on the upper and lower surfaces of the antenna conductor 11 and the first resin portion 12, and the capacitance formed in the antenna conductor 11 by the second resin portion 14 increases, resulting in a resonance frequency. Can be lowered. Therefore, the resonance frequency can be lowered and a wide frequency band can be obtained while reducing the size. Furthermore, since resin molding using a mold is possible, a small antenna can be easily manufactured. In these embodiments as well, deformation of the antenna conductor during resin molding can be suppressed.
[0091]
From the above embodiments, the following inventions and other inventions can be understood.
[0092]
A small antenna according to a first aspect includes an antenna conductor and a dielectric chip formed around the antenna conductor by a plurality of resin moldings. More specifically, the antenna conductor, the first resin portion formed so as to cover a part of the antenna conductor, and the portion of the antenna conductor not covered with the first resin portion are formed. And a second resin portion.
[0093]
With the above configuration, a part of the antenna conductor can be fixed with a mold during the first resin molding. Therefore, deformation of the antenna conductor during molding can be suppressed. Therefore, it is possible to obtain a small antenna with good antenna characteristics and uniform quality, which can be easily manufactured and cost can be reduced.
[0094]
(1) It is preferable to further comprise a protrusion formed on the first resin portion.
(2) It is preferable that the antenna conductor is a planar type, and at least a part of the first resin portion is formed at the same position on the front surface and the back surface of the planar antenna conductor.
(3) As an antenna conductor, it is preferable to use a conductor formed by punching or etching from a metal plate. A conductor formed by bending a wire may be used.
[0095]
(4) The antenna conductor is preferably a meander-shaped antenna conductor.
[0096]
With the above configuration, the first molded resin layer that has been primarily molded can be used as a presser during secondary molding. In particular, secondary molding can be performed without separately forming the pressing member.
[0097]
A small antenna according to a second aspect includes a meander-shaped antenna conductor, a first resin portion formed in a part of a width direction of the meander of the antenna conductor, the first resin portion, and the first resin of the antenna conductor. And a second resin portion formed so as to overlap a portion where the portion is not formed, and the first resin portion has a protrusion formed so as to protrude toward the second resin portion. And In this configuration, it is preferable that the protrusion has the same height as the second resin portion and is formed so as to be disposed at least at three corners of the second resin portion.
[0098]
A small antenna according to a third aspect is formed at a meander-shaped antenna conductor, a first resin portion formed at both ends of the antenna conductor in the width direction of the antenna conductor, and an intermediate portion of the antenna conductor in the width direction of the meander. And a second resin portion formed. By providing the first molding resin layer at both ends in the meandering width direction of the antenna conductor, the both ends of the antenna conductor can be held together. Therefore, secondary molding can be performed while suppressing a change in the distance between the antenna conductors. Thereby, a small antenna with good antenna characteristics and uniform quality can be obtained.
[0099]
A small antenna according to a fourth aspect includes a meander-shaped antenna conductor,
On both surfaces including a first resin portion formed at both ends of the meander width direction of the antenna conductor, a plurality of protrusions formed on both surfaces of the first resin portion, and a first resin portion of the antenna conductor And a second resin portion formed so as to be flush with the protruding portion. 2nd and 3rd aspects WHEREIN: It is also preferable that the said projection part is formed in four corners of the said 1st resin part, or its vicinity. Since the second molded resin layer is formed by being bonded to the boss of the first molded resin layer, an antenna having excellent strength can be configured.
[0100]
In the first to fourth aspects, it is preferable that the resin forming the first resin portion uses a material having higher fluidity at the time of molding than the resin forming the second resin portion.
[0101]
A small antenna according to a fifth aspect includes a first resin portion made of a low dielectric material formed on a side portion of the antenna conductor, and a high dielectric material formed so as to cover the antenna conductor and the first resin portion. And a second resin portion. More specifically, meander-shaped antenna conductors, a first resin portion made of a low dielectric material formed between the conductors of the antenna conductor, and heights provided on the upper and lower surfaces of the antenna conductor and the first resin portion. And a second resin portion made of a dielectric material.
[0102]
With the above configuration, the first resin layer made of the low dielectric material is formed between the conductors of the antenna conductor. Therefore, the frequency band can be maintained in a wide band state. Then, by forming the second resin layer made of a high dielectric material on the upper and lower surfaces of the antenna conductor and the first resin layer, the capacitance formed in the antenna conductor by the second resin layer is increased to increase the resonance frequency. Can be lowered to the target value. Accordingly, it is possible to reduce the resonance frequency to a target value while reducing the size and obtain a wide frequency band. Furthermore, since resin molding using a mold is possible, a small antenna can be easily manufactured.
[0103]
The first resin layer may be provided not only between the antenna conductors but also around the antenna conductor.
[0104]
In the fifth aspect, the first resin portion may be formed of an adhesive having a low dielectric constant, and the second resin portion and the antenna conductor may be bonded via the adhesive.
[0105]
With the above configuration, it is possible to reduce the resonance frequency to a target value and obtain a wide frequency band while reducing the size as in the case of resin molding. In addition, a small antenna can be easily manufactured by simply bonding the first and second resin layers and the antenna conductor.
[0106]
A small antenna according to a sixth aspect includes a meander-shaped antenna conductor, a first resin portion made of a low dielectric material provided between the conductors of the antenna conductor, and the first antenna along the pitch direction of the antenna conductor. An integrally molded portion provided so as to protrude from an upper surface or a lower surface of one resin portion, and a second resin portion made of a high dielectric material provided so as to cover the antenna conductor and the first resin portion. And For example, the integrally molded portion may be provided on both sides or an intermediate portion of the first resin layer.
[0107]
As described above, by providing an integrally molded portion in which the first resin layer protrudes from the upper surface or the lower surface along the pitch direction of the antenna conductor, the resin can be distributed between the antenna conductors through the integrally molded portion. Can do. Thereby, deformation of the antenna conductor from the initial state can be suppressed. Therefore, the secondary forming process can be performed while suppressing the variation in the distance between the antenna conductors. Thereby, a small antenna with good antenna characteristics and uniform quality can be obtained. In addition, by providing the integral molding portion, the integral molding portion can be held by the mating surface of the mold, so that secondary molding processing is facilitated.
[0108]
In the sixth aspect, the second resin portion may be formed so as to cover the integrally molded portion together with the antenna conductor and the first resin portion.
[0109]
In the method for manufacturing a small antenna according to the seventh aspect, a part of an antenna conductor is sandwiched between mating surfaces of a first mold, a first resin part is formed on the antenna conductor, and the first resin part of the antenna conductor is formed. Is sandwiched between the mating surfaces of the second mold, and a second resin portion is formed on the antenna conductor.
[0110]
Another method for manufacturing a small antenna according to the seventh aspect is that the antenna conductor is sandwiched between the mating surfaces of the first mold, the first resin portion is formed on the antenna conductor, and the pressing protrusion is formed on the first resin portion. And forming a second resin portion on the antenna conductor by sandwiching a pressing projection formed on the first resin portion of the antenna conductor between the mating surfaces of the second mold. When the antenna conductor has a meander shape, the part is preferably a part in the width direction of the meander.
[0111]
According to said manufacturing method, since a part of antenna conductor is pinched | interposed with a metal mold | die at the time of the first resin shaping | molding, a deformation | transformation of the antenna conductor at the time of shaping | molding can be suppressed. In addition, since the second molding is performed in a state where the molding resin layer of the first resin portion is sandwiched between the mating surfaces of the second mold, the position of the primary molded product is stabilized. Therefore, a high-quality and high-precision small antenna can be efficiently manufactured.
[0112]
A pressing protrusion may be formed on the first molding resin layer.
[0113]
Moreover, as the material for forming the first resin portion, a material having higher fluidity at the time of molding than the material for forming the second resin portion may be used. After the antenna conductor is fixed without difficulty in the first step, the second step can be formed. In addition, it is preferable to use a material having a lower dielectric property than the material forming the second resin portion as the material forming the first resin portion.
[0114]
In addition, at least one of the first metal mold or the second metal mold sandwiching the antenna conductor or the first resin portion is urged by at least one of the mating surfaces by an elastic body, and the antenna conductor or It is good to provide the member which presses with respect to the said 1st resin part. Since the force for pressing the antenna conductor and the first resin can be adjusted by an elastic force, it is possible to prevent the antenna conductor and the frame from being crushed and deformed by the pressure for sandwiching the antenna conductor and the like.
[0115]
The present invention is not limited to the above-described embodiments. Of course, various modifications can be made without departing from the scope of the present invention.
[0116]
【The invention's effect】
According to the present invention, since a part of the antenna conductor is sandwiched between the molds during the first resin molding, the deformation of the antenna conductor during molding can be reduced. Further, since the second molding is performed with the first resin portion sandwiched between the mating surfaces of the second mold, the position of the primary molded product is stabilized. Therefore, a small antenna with uniform quality and accuracy can be efficiently manufactured.
[Brief description of the drawings]
FIG. 1 is a diagram showing a molding state in each molding process of a small antenna according to a first embodiment of the present invention.
FIG. 2 is a view showing a molding process of a small antenna in the first embodiment.
FIG. 3 is a diagram showing an example in the case where a molding process is performed by providing a pressing protrusion on the first resin portion in the first embodiment.
FIG. 4 is a view showing a molding state in each molding process of a small antenna according to a second embodiment of the present invention.
FIG. 5 is a view showing a molding process of a small antenna in the second embodiment.
FIG. 6 is a view showing a molding state in each molding process of a small antenna according to a third embodiment of the present invention.
FIGS. 7A and 7B are a cross-sectional view and a top view showing a state when a compact antenna according to a fourth embodiment of the present invention is primary molded.
FIG. 8 is a cross-sectional view showing an example in which the island-shaped portion of the first resin layer is formed to protrude from the front surface and the back surface in the fourth embodiment.
FIG. 9 is a view showing a molding state in each molding process of a small antenna according to a fifth embodiment of the present invention.
FIG. 10 is a diagram showing a relationship between a width between conductors of an antenna conductor and a conductor width in the fifth embodiment.
FIG. 11 is a cross-sectional view of a small antenna according to a sixth embodiment of the present invention.
FIG. 12 is a diagram showing a pattern example of an antenna conductor used in a prototype example of the present invention.
FIG. 13 is a diagram showing frequency characteristics of a small antenna in a prototype of the present invention.
FIG. 14 is a diagram showing frequency characteristics of a small antenna manufactured by a conventional method.
FIG. 15 is a view showing a molding state in each molding step of a small antenna according to a seventh embodiment of the present invention.
FIG. 16 is a view showing a molding state in each molding process of a small antenna according to an eighth embodiment of the present invention.
FIG. 17 is a view for explaining problems of a conventional manufacturing method.
FIG. 18 is a perspective view of a primary molded product of a small antenna according to a ninth embodiment of the present invention.
FIG. 19 is a view when the primary molded product of FIG. 18 is set in a secondary molding die.
FIG. 20 is a diagram showing an overview of a small antenna after secondary molding in the ninth embodiment.
FIG. 21 is a view for explaining problems of a conventional manufacturing method.
FIG. 22 is a cross-sectional view showing a case where an antenna conductor is set in a primary molding die in the tenth embodiment.
FIG. 23 is a perspective view and a cross-sectional view of the primary molded product molded in FIG.
FIG. 24 is a cross-sectional view, a top perspective view, and a back perspective view of a small antenna after secondary molding.
FIG. 25 is a view showing the method of manufacturing the small antenna according to the eleventh embodiment.
[Explanation of symbols]
10 ... Small antenna
11 ... Antenna conductor
11a ... Insert frame
12 ... 1st resin part
12a ... through hole
12c: Presser protrusion
13 ... Resin layer
14, 14a, 14b ... second resin layer
15 ... Feeding terminal

Claims (11)

A meander-shaped planar antenna conductor;
  A portion of the antenna conductor is sandwiched between mating surfaces of the first mold, and a first resin portion formed between the conductors of the antenna conductor by resin molding;
  A second resin portion formed between the antenna conductor and the first resin portion formed between the conductors by sandwiching the first resin portion between the mating surfaces of the second mold; And
  The small antenna, wherein the resin forming the first resin portion is made of a material having higher fluidity at the time of molding than the resin forming the second resin portion. The first resin portion has an integrated molded portion that covers and holds a part of the antenna conductor in the width direction,
  The small antenna according to claim 1, wherein the second resin portion is formed so as to cover a portion of the antenna conductor that is not covered with the first resin portion. The small antenna according to claim 2, wherein the integrally molded portion is formed at the same position on the front surface and the back surface of the planar antenna conductor. The second resin portion covers the first resin portion, the first resin portion has a protrusion formed to protrude toward the second resin portion, and the protrusion is a second resin portion. The small antenna according to any one of claims 1 to 3, wherein the small antenna has the same height. The first resin portion is formed at both end portions in the width direction of the meander of the antenna conductor,
  5. The small antenna according to claim 1, wherein the second resin portion is formed at an intermediate portion in a width direction of a meander of the antenna conductor. The small antenna according to claim 4, wherein the protrusion is formed at or near four corners of the first resin portion.   The small antenna according to any one of claims 1 to 6, wherein a dielectric constant of the second resin portion is higher than a dielectric constant of the first resin portion. The first resin part is an adhesive that bonds the second resin part and the antenna conductor, and a dielectric constant of the second resin part is higher than a dielectric constant of the first resin part. Item 2. The small antenna according to Item 1. Sandwiching part of the antenna conductor between the mating surfaces of the first mold,
  Forming a first resin portion on the antenna conductor;
  Sandwiching the first resin part of the antenna conductor between the mating surfaces of the second mold,
  A small antenna comprising a step of forming a second resin portion on the antenna conductor, wherein the resin forming the first resin portion has higher fluidity at the time of molding than the resin forming the second resin portion. Manufacturing method. Sandwich the antenna conductor between the mating surfaces of the first mold,
  Forming a first resin portion on the antenna conductor;
  Forming a pressing projection on the first resin portion;
  Sandwiching the pressing projection formed on the first resin portion of the antenna conductor between the mating surfaces of the second mold,
  A method of manufacturing a small antenna, wherein a second resin part is formed on the antenna conductor, wherein the resin forming the first resin part flows more than the resin forming the second resin part during molding. A method for manufacturing a small antenna, characterized by high performance. 11. The method for manufacturing a small antenna according to claim 9, wherein a material forming the first resin portion is a material having a lower dielectric property than a material forming the second resin portion.

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