JP2003268040A - Dielectric resin material and circuit member molded out of the dielectric resin material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric resin material satisfactorily having mechanical characteristics suitable for a circuit member, especially for a millimeter-wave device which is used in a frequency band of ≥50 GHz, and to provide the circuit member. <P>SOLUTION: This dielectric resin material is used for the circuit member which utilizes electrical radiation of a frequency of ≥50 GHz, wherein the resin material has a coefficient of water absorption of ≤0.01% and a coefficient of thermal expansion of ≤7×10<SP>-5</SP>, and comprises an amorphous synthetic resin. The circuit member is molded by using the resin material. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention generally relates to frequency 3
Circuit members (or millimeter wave devices) used in the frequency band of 0 GHz to 300 GHz millimeter wave (EHF) or higher
In particular, the present invention relates to a millimeter wave device used in a frequency band of 50 GHz or higher.

[0002]

2. Description of the Related Art In recent years, wireless communication systems have been widely used against the backdrop of the highly information-oriented society. In particular, communication systems using the millimeter wave region include a plurality of wireless LANs and collision prevention radars for automobiles. The application in the field of is expected.

In a communication system using the millimeter wave region, the dimensional accuracy of the dielectric member is strict due to the short wavelength, and the stability of the size influences the frequency characteristic under the condition of being installed outdoors. Further, in a circuit member using a radio wave of 50 GHz or more, if the variation of the dielectric loss tangent is not reduced, it will be a practical problem. It has been desired to develop a dielectric resin material that can be molded with high accuracy as such a dielectric member and that is stable and has a small loss even when the temperature is different from the temperature and the humidity is different. For example, in order to reduce the dielectric loss, Japanese Patent Laid-Open No.
JP-A-316829 proposes an olefin monomer having a norbornene-based structure having a low dielectric loss tangent.

[0004]

However, JP-A-10-
Japanese Patent No. 316829 does not disclose a material having a preferable dielectric loss tangent in a band of 50 GHz or more, and the dielectric loss tangent of an olefin monomer having a norbornene-based structure is as large as about 2.4 × 10 ⁻⁴ at 47 GHz, which is high at room temperature.
There is a difficulty in stably using it for a circuit member that uses radio waves of 50 GHz or higher at high temperatures. In addition, JP-A-10
JP-A-316829 also fails to sufficiently consider the mechanical properties of such a material, which can withstand use in an environment where there is a large difference in temperature and dryness.

Therefore, it is an exemplary object of the present invention to provide a material satisfying mechanical characteristics suitable for a millimeter wave device used in a frequency band of 50 GHz or more and a millimeter wave device using the material. To do.

[0006]

In order to achieve the above object, the dielectric resin material according to one aspect of the present invention has a water absorption of 0.01% or less and a thermal expansion coefficient of 7 × 10 ⁻⁵ or less. It can be used for a circuit member that uses radio waves of 50 GHz or higher made of crystalline synthetic resin. Since such a dielectric resin material has a small water absorption rate of 0.01% or less, it is practically unaffected by changes in characteristics due to moisture, and can be used in wet weather or near water. Further, the coefficient of thermal expansion (or the coefficient of linear expansion) is as small as 7 × 10 ⁻⁵ or less, because the operation becomes unstable in practice if the coefficient of linear expansion is too large. In this way, the mechanical characteristics are secured by limiting the range of the absorption coefficient and the coefficient of thermal expansion. Further, a resin material is suitable for injection molding, and particularly, amorphous is suitable for molding with high accuracy.

The dielectric resin material is, for example, an amorphous polyolefin, preferably a copolymer containing dimethanonaphthalene and its derivative. Further, the dielectric resin material has a dielectric loss tangent of 2.0 × 10 ⁻⁴ or less, preferably,
Since it has 1.8 × 10 ⁻⁴ or less, the dielectric loss can be suppressed to be low and the electrical characteristics can be maintained.
A circuit member formed by injection molding using the above-mentioned dielectric resin material also constitutes one aspect of the present invention. In the formation of a circuit member by this injection molding, if a crystalline resin is used as the dielectric resin, distortion due to the molding becomes remarkable, which adversely affects the circuit characteristics. Therefore, it is preferable to use an amorphous resin to achieve this object.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors consider first the loss due to resonance by radio waves due to the inclusion of unsaturated double bonds, ether bonds, hydroxyl groups, nitrogen, phosphorus, and sulfur, and Amorphous resin,
Regarding resin materials such as polycarbonate, polytetrafluoroethylene, polypropylene and polystyrene, 5
It was examined whether there is a circuit member that can be used in a frequency band of 0 GHz or higher. The dielectric loss tangent is, for example, 50 GHz at a value of the dielectric loss tangent of about 1 MHz.
The above characteristics cannot be predicted. The dielectric loss tangent of about 1 MHz is about the same for amorphous polyolefin, polytetrafluoroethylene, and polypropylene, but is slightly inferior to polystyrene, but at 50 GHz, polystyrene has a large dielectric loss tangent of 7 to 10 × 10 ⁻⁴ , which leads to a loss of a circuit. This is probably because it contains a benzene ring. On the other hand, according to Japanese Patent Laid-Open No. 10-316829, polypropylene has a large dielectric loss tangent of about 6 × 10 ⁻⁴ even at about 10 GHz, which is insufficient at 50 GHz. The lower the dielectric loss tangent, the more preferable it is, but the dielectric loss tangent allowable in the present invention is 2.0 × 10 ⁻⁴ , preferably,
It is 1.8 × 10 ⁻⁴ . Further, polypropylene has a linear expansion coefficient too large to be used in a wide temperature range. If the linear expansion coefficient is too large, the operation becomes unstable in practical use.

In the present invention, in addition to the chemical structure of the material and the dielectric loss tangent derived from it, the fact that the transmission efficiency is significantly affected by the difference in temperature and temperature and the difference in dryness and humidity in the circuit member using radio waves of 50 GHz or higher. Since I encountered this, I needed to select a resin material that can be used stably, and I had to revise the guideline for material selection. The two conditions of the water absorption coefficient and the thermal expansion coefficient are, in particular, that a circuit member using a radio wave of 50 GHz or more can reduce fluctuations due to a difference in dryness and humidity and a difference in temperature, and that it is highly accurate that it is amorphous. It is an indispensable condition for molding with.

These conditions were conditions that did not pose a practical problem at about 10 to 40 GHz. In particular, the dimensional accuracy in millimeter waves is required to be suppressed to at least 1% or less of the wavelength, and for example, the accuracy of several tens of μm is required at 60 GHz. The degree of precision is also affected by crystallization during the cooling process during injection molding.
Therefore, it is desirable that the material is amorphous as a molding material. This accuracy should also be such that it is not disturbed during use.

[0011]

EXAMPLES Table 1 shows injection-molded plastic resin materials. Using such a resin material, a transmission characteristic evaluation experiment was conducted after an environmental test using a resonance circuit composed of a strip line operating in a frequency band of 50 GHz.

[0012]

[Table 1]

The one with the smallest fluctuation range of characteristics is the ammo
It was a rufus polyolefin. Amorphous polio
The refin also has a dielectric loss tangent of about 1.3 at about 38 GHz.
0x10^-4Through 1.50x10^-4And is 50GH
about 1.8x10 in z ^-4The following and JP-A-10-3
Approximately 2.5 × 10 of 16829 publication^-4Much smaller than
It turned out to be a good value. In addition, amorphous polyolefin
Dimethanonaphthalene having the following chemical formula in fins
The structure was particularly excellent in properties.

[0014]

[Chemical 1]

A planar antenna 100 to which the dielectric resin material of the present invention can be applied will be described below with reference to the accompanying drawings. In each drawing of the attached drawings, members with the same reference numerals represent the same members, and duplicated description will be omitted. Here, FIG. 1 shows a planar antenna 10 of the present invention.
It is a schematic perspective view which shows one surface of 0. FIG. 2 is a schematic perspective view showing the other surface of the planar antenna 100 shown in FIG. FIG. 3 is a schematic sectional view of the planar antenna 100 shown in FIG.

As shown in FIG. 3, the planar antenna 100 of the present invention has a substrate 110 and a conductor film 120, and the conductor film 120 is formed on the substrate 110 with a predetermined thickness to avoid the skin effect. ing. However, the planar antenna 100
In the above, the conductor film 120 is not formed in a predetermined region (the slot pattern 114 and the power feeding slot pattern 116 described later) of the substrate 110, and the predetermined region serves as a slot to function as an antenna. In addition,
1 to 3, for convenience, the sizes of the slot pattern 114 and the power feeding slot pattern 116 are exaggerated and partially omitted.

In the present embodiment, the antenna 100 has a disk shape with a diameter of 30 to 50 mm and a thickness of 1 mm, for example, and is realized as a small radial slot antenna. However, the application of the antenna 100 of the present invention is not limited to this, and for example, the conductor coating surface 106 such as a patch antenna or a microstrip antenna.
The present invention is applicable to any antenna configured as a dielectric having a region in which a conductor is not covered, and the size is not limited. However,
The planar antenna 100 of the present invention has an advantage that it can be manufactured with high dimensional accuracy even if it is small.

The substrate 110 has a predetermined thickness, and the thickness portion serves as a waveguide and functions as a power feeding circuit to each slot. The substrate 110 has a substrate body 112, a slot pattern 114, and a power feeding slot pattern 116. In the present specification, the portion of the substrate 110 on which the conductor film 120 is formed except the slot pattern 114 and the feeding slot pattern 116 is defined as the conductor coating surface 106. As shown in FIGS. 1 to 3, in the planar antenna 100, the slot pattern 114 is convex on one surface (radiating surface) 102 side and the feeding slot pattern 116 is convex on the other surface (feeding surface) 104 side. Are integrally formed with the substrate 110. However, as will be described later, the slot pattern 114 and the power feeding pattern 116 may be configured to have a concave shape. The substrate 110 is shown in FIG.
And as shown in FIG. 2, the front and back sides (radiation surface 102 and feeding surface 1
04), the patterns (slot pattern 114 and feeding slot pattern 116) are different. Then, as described in the manufacturing process described later, it is usual that the front and back patterns (slot pattern 114 and power feeding slot pattern 116) need to be aligned. Therefore, as the substrate 110, a front pattern molding substrate (for example, a substrate having the slot pattern 114) and a back pattern molding substrate (for example, a substrate having the power feeding slot pattern 116) are separately molded, and then the both substrates are bonded to each other to be integrated. It is also possible to adopt a manufacturing process for changing the manufacturing method. Of course, the substrate 110 is
As in this embodiment, front and back patterns (slot pattern 1
It is needless to say that it is possible to manufacture a substrate integrally formed with 14 and the feeding slot pattern 116).

As described above, in the substrate 110 of the present invention, the slot pattern 114 and the feeding slot pattern 1 are formed as the regions where the conductor film 120 is not formed on the conductor coating surface 106.
16 is integrally formed on the substrate 110 in a convex shape (or a concave shape). The substrate 1 including the slot pattern 114 and the feeding pattern 116 in the present embodiment
10 is integrally molded by the injection molding method using the above-mentioned amorphous polyolefin as a dielectric. As described above, the slot pattern 114 constitutes a slot of the plane antenna, but the injection molding method can mold the slot pattern 114 and the feeding slot pattern 116 with micron accuracy. For example,
An optical disc is given as an example of the optical disc formed by injection molding.
In D), width 0.3 μm, length 0.4 μm, depth 0.0
4 μm pits can be formed with high precision. The substrate 1 of the present invention uses the molding technique capable of molding with such high precision.
The use of 10 becomes a slot of the antenna 100 with high dimensional accuracy, and the small antenna 100 suitable for shortening the wavelength is provided.
Can be accurately molded. Further, if the die of the substrate 110 including the slot pattern 114 and the feeding slot pattern 116 is created by using the derivative forming technique by the injection molding method, the antenna 100 can be mass-produced easily and the antenna 100 can be manufactured at low cost. be able to.

The slot pattern 114 is used for the antenna 100.
This is a pattern for forming a region that does not cover the conductor film 120 that functions as a slot. As shown in FIG. 4, the slot patterns 114 are arranged in a plurality of arrays, but as described above, the substrate 110 is formed by injection molding.
Since the slot pattern 114 formed integrally with the antenna is formed with high dimensional accuracy, the directivity of the antenna 100 can be maintained. In this embodiment, the slot pattern 114 is composed of a pair of patterns 114a and 114b, and the slot pattern 114 is the substrate body 112.
Although it is formed in a spiral shape on the upper side, it is also possible to form a concentric arrangement. Here, FIG. 4 shows V surrounded by a solid line in FIG.
It is a partially expanded perspective view of the board | substrate 110 which shows a character area. However, the form of the slot pattern 114 shown in FIG.
It is sufficient to be molded to function as a zero slot. Note that the antenna 100 having different characteristics can be obtained in the concentric shape with the spiral.

The patterns 114a and 114b are required to have a dimensional accuracy of at least 1% of the wavelength in the millimeter wave. For example, in 60 GHz, an accuracy of several tens of μm is required. As described above, the pattern shape is realized as a difference in depth in the molding of the optical disc, which must be expressed as the presence or absence of the conductor in the antenna 100. For example, the slot antenna is an opening except the conductor of the pattern portion, the patch antenna is an antenna leaving the conductor of the pattern portion, and the like. The difference in depth due to molding is 0.03 μm to 0.0 for optical disks.
It is about 7 μm and very shallow. However, it is simply difficult to differentiate the presence or absence of a conductor based on this difference in depth. Therefore, in the present invention, the patterns 114a and 11
It should be noted that the height of 4b is set to several μm or more and several tens of μm, and it is possible to differentiate the presence or absence of the conductor by the difference in height. The pattern 114
It is necessary to increase the heights of a and 114b as much as the thickness of the conductor film 120 formed on the substrate 110 increases.

The feeding pattern 116 is a pattern for forming a region which does not cover the conductor film 120 which functions as a feeding slot of the antenna 100. The power feeding pattern 116 has, for example, a cylindrical shape and is formed at the center of the substrate 112. The power feeding slot in which the power feeding slot pattern 116 functions is the antenna 100.
Since the radiated power pattern has a biased characteristic when power cannot be fed to the center of the slot, the power feeding pattern 116 is accurately provided at the spiral center of the slot pattern 114 described above.

The conductor film 120 is a conductor portion provided on the substrate 110, and is formed to have a predetermined thickness so that the conductor coating surface 106 of the substrate 110 is not affected by the skin effect. Copper, silver, and nickel are generally used as the conductor material, but the conductor film 120 may have a multilayer structure of the conductor, if necessary. Although not shown, the conductor film 120 directly formed on the substrate 110 is a portion that is constructed electrolessly and can be formed by electroless plating, sputtering or vapor deposition, and is made of chromium, nickel, copper, silver, gold, or the like. Configured (first conductor). Then, the conductor to be covered next constitutes a large part of the thickness of the conductor film 120 in the portion subjected to the electroplating treatment (second conductor). Such a conductor also has different density and electric characteristics depending on the current density and the temperature of the electrolytic solution. As described above, the conductor film 120, that is, the second conductor, has a conductor thickness controlled by controlling the current value and the plating time in order to secure the thickness in order to avoid the skin effect. In addition, this layer is further used as a multi-layer film, the interface layer with the dielectric through which a large amount of current flows is formed as a silver or copper layer, and the layer far from the dielectric is formed of gold or nickel in consideration of cost and acid resistance. It is also possible to use materials.

The planar antenna 100 may be coated with resin for the purpose of protecting the conductor film 120 to form a protective layer for the antenna 100 (not shown here). Such a protective layer aims at protection from rust and scratches, and is necessary as a dustproof measure when the antenna 100 is installed without using a cover material such as a radome. However, the coating layer is required to be a material having a small dielectric loss due to the electrical characteristics of the antenna 100, but a method of coating a UV curable resin can also be applied.

Next, a method of manufacturing the above-described antenna 100 will be described with reference to FIGS. Here, FIG. 5 is a flowchart showing a method for manufacturing the antenna 100 shown in FIG. 6 is a diagram showing the details of step 1000 shown in FIG. 5, and FIG. 7 is a diagram showing the details of step 1005 shown in FIG. FIG. 8 is a flowchart showing details of step 1010 shown in FIG. 9A is a schematic perspective view corresponding to FIG. 4 showing a state before the conductor film 120 is peeled off, and FIG. 9B is a state where the conductor film 120 is peeled off from the state shown in FIG. 9A. FIG. 5 is a schematic perspective view corresponding to FIG. 4 shown. 10A is a schematic perspective view showing a radiation surface 102 of the antenna 100 manufactured by the manufacturing method shown in FIG. 5, and FIG. 10B shows a radiation surface 104 of the antenna 100 shown in FIG. 9A. It is a schematic perspective view shown. Note that, in FIGS. 9 and 10, in order to clarify the presence or absence of the conductor film 120, the portion where the conductor film 120 is formed is illustratively drawn in black.

First, as described above, since the substrate 110 of the antenna 100 is molded by the injection molding method, a mold for molding the substrate 110 having the slot pattern 114 and the feeding pattern 116 is prepared (step 10).
00). In the step 1000, the mold is divided into two parts on the radiation surface 102 side and the power feeding surface 104 side of the substrate 110.
One is created.

In order to explain step 1000 in more detail, first, a master M coated with an exposure resist is prepared (FIG. 6 (a)). A master having a flat surface made of glass is used, and an exposure resist R is applied thereon (FIG. 6B). Next, the resist-coated master is exposed through a pattern mask m using an exposure device or the like (FIG. 6C). The pattern mask m represents the slot pattern 114 or the feeding slot pattern 116 designed in advance by CAD, and it is preferable to use the pattern mask m created based on the result of simulation (in FIG. 6C, radiation A surface 102, that is, a pattern mask m representing the slot pattern 114 is drawn).

After exposure (FIG. 6D), the master M is developed to develop the slot pattern 114 or the power feeding slot pattern 1.
A pattern corresponding to 15 is made to stand out. More specifically, since the exposed part or the unexposed part is dissolved in the developing solution by developing the exposed master M, the resist layer in the exposed part or the unexposed part is removed, whereby the slot pattern 114 or the power feeding is performed. A pattern (inverted) corresponding to the slot pattern 115 for use is formed as shown in FIG. It should be noted that this pattern is the slot pattern 114 and the power feeding slot pattern 116 that are actually created.
It is formed in a larger size, and the shape dimension is determined in consideration of shrinkage after molding. Therefore, it should be noted that if the setting of the contraction rate is different, the physical size of the antenna is different and desired characteristics cannot be obtained. In addition, the heights of the slot pattern 114 and the feeding slot pattern 116 are the same as those of the antenna 100 according to the present invention, so that the slot pattern 114 and the feeding slot pattern 116 can be processed by differentiating the presence or absence of a conductor based on the difference in height. It must be kept in mind that the pattern of the master M needs to be formed so as to have a wavelength of about 1% and about several tens of μm, which is different from the optical disk manufacturing method. Then, after the master is developed, a chrome film is formed and electroplating is performed, so that the mold S ₁ can be manufactured. Although only the mold S ₁ on the radiation surface 102 side is shown in FIG. 6, a mold S ₂ on the power feeding surface 104 side is also created in the same manner.

Molds S ₁ and S ₂ produced in this process
Then, the portion of the substrate 110 corresponding to the radiation surface 102 and the power feeding surface 104 has a concave shape, and such a portion can form a convex pattern on the substrate 110. As described above, if the molds S ₁ and S ₂ of the substrate 110 including the radiation surface 102 and the power feeding surface 104 are molded, the antenna 100 can be mass-produced easily and the antenna 100 can be molded at low cost. .

Next, referring to FIG. 7A, the substrate 110 is molded using the molds S ₁ and S ₂ (step 1005). The substrate 110 uses a well-known injection compression molding device to send a molding resin material to the molding device, and heats it up to, for example, about 350 ° C. to uniformly dissolve the resin material, and press it into the stamper molds S ₁ and S _{2 under} high pressure. It is molded by injection (FIG. 7 (b)). The injection compression molding device is not shown in FIG. 7 (b). As a result, the radiation surface 1
02 and the feeding surface 104 are integrally formed on the substrate 110 (FIG. 7C). Such slot pattern 1
14 and the slot pattern 116 are patterns in which protruding rectangular parallelepipeds are arranged in an array. In injection molding method,
It is possible to faithfully reproduce the sizes and arrangements of the slot pattern 114 and the power feeding slot pattern 116, and it is possible to create a substrate 110 with high accuracy and excellent directivity of the antenna 100.

It should be noted that, in this step 1005, it is necessary to accurately align the center positions of the die on the radiation surface 102 side and the die on the power feeding surface 104 side. If the power cannot be fed to the center of the spiral slit pattern 114, the characteristics eccentric to the radiated power pattern will occur. Therefore, in order to manufacture the antenna 100 having a slot with good symmetry, center alignment of the molds S ₁ and S ₂ is important. Further, in the present embodiment, the pattern of the radiation surface 102 and the power feeding surface 104 of the substrate 110 is integrally formed by using the molds S ₁ and S ₂ at the same time. However, as described above, the dies S ₁ and S ₂ are individually used and injection-molded, so that the radiation surface 102 and the power feeding surface 1 are formed.
The substrate 110 may be obtained by creating two substrates having No. 04 and bonding the two substrates. Of course, it is preferable that the two substrates are injection-molded to have a thickness half that of the substrate 110 in which the slot pattern 114 and the feeding slot pattern 116 are integrally molded.

Next, the conductor film 120 is formed on the substrate 110 formed in step 1005 (step 101).
0). Referring to FIG. 8, first, a (first) conductor thin film is formed by using electroless treatment, for example, a conductor film deposition by an evaporation method or a sputtering method or an electroless plating treatment (step 1012). Such a conductor is composed of copper, chromium, nickel, silver, gold or the like. Next, a (second) conductor is further formed on the conductor so as to have a predetermined thickness in order to avoid the skin effect. Such a forming means can be formed by, for example, electrolytic plating, and the conductor film 1 can be formed by controlling the current value and the plating (energization) time so that the film has a predetermined film thickness.
A second conductor is formed to avoid the skin effect of 20 (steps 1014-1016). The electroplating method is to immerse an object to be treated in an aqueous solution containing a target metal ion, and use this as a cathode of an electrode in which a reduction reaction occurs, while using a suitable soluble or insoluble anode (an electrode in which an oxidation reaction occurs). This is a method in which a forward direct current is applied between the electrodes to electrolytically deposit a film of the target metal on the surface of the object to be processed. The thickness of the conductor film 120 can be known directly or indirectly by measuring the elapsed time after energization, the current value during energization, and the like. When the thickness of the conductor film 120 is detected by the elapsed time after energization or the current value during energization, data obtained by simulation in advance can be used. In general, it is expected that the smaller the film thickness of the conductor film 120, the lower the current value. Such a simulation will be performed in consideration of parameters such as the concentration of metal ions, the temperature of the aqueous solution, and the humidity. Since the method of forming the conductor described above can be easily understood by those skilled in the art, detailed description thereof is omitted here.

Step 1010 (ie, step 101
After 2 to 1016), the conductor film 120 is uniformly formed on the slot pattern 114, the feeding pattern 116 and the substrate body 112. Note that in this state, the slot pattern 114 and the feeding pattern 116 are uneven patterns formed by coating a conductor, and no electrical antenna pattern is obtained (FIG. 9A). Therefore, the conductor film 120 of the slot pattern 114 and the feeding slot pattern 116 is peeled from this state (step 101).
5). In step 1015, the conductor film 120 attached to the slot pattern 114 and the power feeding slot pattern 116 can be peeled off by mechanical means such as polishing work. If the flatness of the emitting surface 102 is not sufficient, the polishing will be biased and the peeling will not be successful. Therefore, it is important to perform molding under molding conditions that do not deform. Further, in order to allow a slight amount of unevenness, it is better to work from the state of electroless plating to electrolytic plating to increase the film thickness of the conductor film 120. As for the relationship between the film thickness of the conductor film 120 and the heights of the slot pattern 114 and the feeding slot pattern 116, the higher the conductor film thickness, the higher the height must be. Therefore, it is more efficient in the polishing process to perform the polishing in the electroless plating step in which the conductor film thickness is smaller than that after the electroplating, and the height of the slot pattern 114 and the feeding slot pattern 116 can be reduced. .

Through steps 1000 to 1015 described above, the antenna 100 is a slot antenna in which the conductor film 120 is not coated on the predetermined regions (slots and feeding slots) on the substrate 100 as shown in FIGS. 9B and 10. Configured as. Although only the slot pattern 114 is shown in FIG. 9B, the conductor 120 is also removed from the power feeding slot pattern 116 of the power feeding surface 104 as shown in FIG. 10B.

In this embodiment, a slot antenna having no conductor in the slot pattern 114 is shown as an example, but in the case of a patch antenna, for example, the slot pattern 114 is formed as the conductor film 120. There is no change in the manufacturing method. Also, the substrate 11
The side surface of 0 is coated with the conductor film 120, but if the conductor on the side surface is removed by polishing, it becomes an open type antenna. Although not described in detail, it is a matter of course that the coating process is performed for the purpose of protecting the antenna, but particularly on the radiating surface 102 side, there is a relation with the electrical characteristics, so that careful measures are required.

Although the above description is for the case where the slot pattern 114 has a convex shape, the slot pattern 114 can also have a concave shape as described above. However, although it is not possible to form a pattern in a concave shape by polishing, it is possible to devise a pattern in the step of forming the conductor film. Hereinafter, such a method will be described with reference to FIGS. 11 and 12. Here, FIG. 11 and FIG. 12 are flowcharts showing another manufacturing method of the antenna 100 of the present invention. Note that description of steps that are the same as those of the method described above will be omitted.

As described above, the substrate 1 of the antenna 100
Step 10 for molding 10 by injection molding.
A mold for forming the substrate 110 having the slot pattern 114 and the power feeding pattern 116 is created in the same manner as 0 (step 2000). In this step, the mold is the radiation surface 102 of the substrate 110 and the power feeding surface 10.
Two of four are created. Unlike step 1000,
In the master prepared in this process, the slot pattern 114 (and the power feeding slot pattern 1 of the substrate 110 is
The portion corresponding to 16) has a convex shape, and such a portion is formed on the substrate 110 as a pattern having a concave shape. As will be apparent from the process described below, it is preferable that the convex portion is formed so that the slot pattern 114 of the substrate 110 is deep to some extent, and the depth is such that the conductor is coated on the bottom of the slot pattern 114. Has the effect of making it difficult.

Next, the substrate 110 is molded by using such a mold (step 2005). As a result, the substrate 110 in which the slot pattern 114 and the power feeding slot pattern 116 are integrally formed is formed. As described above, the substrate having the slot pattern 114 and the power feeding slot pattern 116, respectively, is bonded to the substrate 1
You may create 10. Such slot pattern 114
(And the slot pattern 116) is a rectangular parallelepiped recessed pattern. With the injection molding method, the size and arrangement of the slot pattern 114 and the power feeding slot pattern 116 can be faithfully reproduced. It should be noted that, in this step, it is necessary to accurately align the center positions of the die on the radiation surface 102 side and the die on the power feeding surface 104 side, as in the above-described process. If the power cannot be fed to the center of the spiral slit pattern 114, the characteristics eccentric to the radiated power pattern will occur. Therefore, in order to manufacture the antenna 100 having a slot with good symmetry, center alignment of the mold is important.

Next, the conductor film 120 is formed on the substrate 110 formed in step 2005. More specifically, first, a conductor is constructed by electrolessly forming a portion near the substrate 110 (first
Conductor). The conductor can be formed by, for example, a vapor deposition method or a sputtering method. At this time, it should be noted that the conductor is not attached to the bottom surfaces of the slot pattern 114 and the feeding slot pattern. Therefore, in the method of the present invention,
The substrate 110 is arranged obliquely with respect to the flying direction of the conductor particles so that the bottom surface of the slot pattern 114 (and the feeding slot pattern 116) is located in the shadow of the flying conductor particles (step 2010). Then, in such a state, the conductor is jetted by the vapor deposition method or the sputtering method (step 2015). At this time, if the distance between the conductor ejection port and the substrate 110 is short, unevenness of the film thickness occurs on a part of the substrate 110. Therefore, it is preferable to form the film with a sufficient distance between the substrate 110 and the ejection port. . Such a conductor is made of chromium, nickel, silver, gold or the like. next,
A (second) conductor is further formed on the conductor so as to have a predetermined thickness so as to obtain a skin effect (step 20).
20). The second conductor can be formed by vapor deposition or sputtering of aluminum, for example.

Such steps 2000 to 2020
After that, the antenna 100 is configured as a slot antenna in which a predetermined area (slot and feeding slot) on the substrate 100 is not covered with the conductor film 120.

On the other hand, referring to FIG. 11, step 20
The steps 00 to 2020 may be replaced by the method described below. First, as in the above process, the antenna 1
Since the substrate 110 of No. 00 is molded by the injection molding method, a mold for molding the substrate 110 having the slot pattern 114 and the feeding pattern 116 is prepared (step 3000). In addition, in this step, two dies, that is, the radiation surface 102 and the power feeding surface 104 of the substrate 110 are formed. In the master prepared in this step, a portion of the substrate 110 corresponding to the slot pattern 114 (and the power feeding slot pattern 116) has a convex shape, and the portion is formed on the substrate 110 as a pattern having a concave shape. However, as described above, the substrate 110 may be formed by bonding the substrates having the slot pattern 114 and the power feeding slot pattern 116, respectively.

Next, the substrate 110 is molded by using such a mold (step 3005). As a result, the substrate 110 in which the slot pattern 114 and the power feeding slot pattern 116 are integrally formed is formed. The slot pattern 114 (and the slot pattern 116) is a rectangular recessed pattern. In the injection molding method, the slot pattern 114 and the power feeding slot pattern 11 are used.
It is possible to faithfully reproduce the size and arrangement of 6.
Note that the radiation surface 102 should be noted in this step.
That is, the center positions of the mold on the side and the mold on the side of the power feeding surface 104 must be accurately matched. If the power cannot be fed to the center of the spiral slit pattern 114, the characteristics eccentric to the radiated power pattern will occur. Therefore, in order to manufacture the antenna 100 having a slot with good symmetry, center alignment of the mold is important.

Next, a dummy member is embedded in the slot pattern 114 of the substrate 110 (step 301).
0). In the above method, in order to prevent the conductive film from being formed on the slot pattern 114 of the substrate 110, the substrate 1
Although a method of forming a conductor on 10 has been devised, such a problem is solved in the present embodiment by providing a step of embedding a dummy member in the concave portion of the substrate 110. The dummy material to be embedded in the recesses of the slot pattern 114 is to remove the dummy material after the conductor is formed and consequently remove the conductor film 120 in the recesses. Therefore, it is necessary to take measures so that the dummy material remains only in the concave portion and not in the flat portion. Further, the dummy material needs to be taken out after the conductor film is formed.
It is preferable to rupture 20 and make it pop out. As the dummy material, a material that is solid at room temperature and expands into a gas by heating is preferable, and, for example, petrolatum or the like can be used.

Next, the conductor film 120 is formed on the substrate 110 formed in step 3010 (step 301).
5). This substrate 110 is processed in step 1012 shown in FIG.
As described in 10 to 1016, the conductor is formed by using the electroless plating means, for example, the conductive film deposition by the vapor deposition method or the sputtering method or the electroless plating treatment. Such conductor is
It is composed of copper, chromium, nickel, silver, gold, etc. next,
Such a conductor is formed with a large thickness so as to have a predetermined thickness or more in order to avoid the skin effect. Such forming means are
For example, it can be formed by electrolytic plating, and the thickness of the conductor can be controlled by controlling the current value and the plating time. The method for forming such a conductor is as described above, and detailed description thereof is omitted here.

Then, the conductor film 120 on the slot pattern 114 is peeled off by removing the dummy member (step 3020). As described above, when vaseline or the like is used for the dummy member, heating the substrate 110 on which the conductor film 120 is formed vaporizes the petrolatum, which causes the vaseline trapped inside the conductor film 120 to burst. Thus, the conductor film 120 can be peeled off.

Through the steps 3000 to 3020, the antenna 100 is constructed as a slot antenna in which the conductor film 120 is not coated on the predetermined region (slot and feeding slot) on the substrate 100.

In the manufacturing method described above, the slot pattern 114, the power feeding slot 116, and the substrate body 112 can be integrally formed by injection molding. The slot pattern 114 is a portion that functions as a slot of the planar antenna, and the injection molding method can mold a predetermined pattern in units of microns. Therefore, the manufacturing method described above allows the slot to be formed with high dimensional accuracy, and a small antenna suitable for shortening the wavelength can be molded. It should be noted that when the substrate 110 is formed by the injection molding method, once the dielectric mold including the predetermined pattern is molded, mass production of the antenna is easy, and the antenna can be molded at low cost.

The antenna 100 of the present invention is a small planar antenna suitable for the millimeter wave band (frequency 30 to 300 GHz, radio wave of wavelength 1 to 10 mm). Especially 50G
In addition to this feature, the Hz band has physical characteristics such that absorption and attenuation by oxygen are large and does not reach a long distance, and it is applicable to various wireless systems with large capacity and low cost. The antenna 100 is, for example, a radar for preventing a vehicle collision,
It is suitable for short-distance communication systems, wireless LANs, and wireless indoor wiring at home.

The preferred embodiments of the present invention have been described above, but the present invention can be variously modified and changed within the scope of the gist thereof.

[0050]

According to the present invention, it is possible to provide a material satisfying mechanical characteristics suitable for a millimeter wave device used in a frequency band of 50 GHz or more, and a millimeter wave device using the material.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing one surface of a planar antenna of the present invention.

FIG. 2 is a schematic perspective view showing the other surface of the planar antenna shown in FIG.

FIG. 3 is a schematic sectional view of the planar antenna shown in FIG.

FIG. 4 is a partially enlarged perspective view of a substrate showing a V-shaped region surrounded by a solid line in FIG.

5 is a flowchart showing a method for manufacturing the antenna shown in FIG.

FIG. 6 is a diagram showing details of step 1000 shown in FIG. 5.

FIG. 7 is a diagram showing details of step 1005 shown in FIG.

8 is a diagram showing details of step 1010 shown in FIG. 8. FIG.

9A is a schematic perspective view corresponding to FIG. 4 showing a state before the conductor film 120 is peeled off, and FIG. 9B is a state where the conductor film 120 is peeled off from the state shown in FIG. 9A. It is a schematic perspective view corresponding to FIG. 4 which shows a state.

10A is a schematic perspective view showing a radiation surface of an antenna manufactured by the manufacturing method shown in FIG. 5, and FIG.
FIG. 3 is a schematic perspective view showing a radiation surface of the antenna shown in FIG.

FIG. 11 is a flowchart showing another method of manufacturing the antenna of the present invention.

FIG. 12 is a flowchart showing another method for manufacturing the antenna of the present invention.

[Explanation of symbols] 100 antenna 102 Radiating surface 104 feeding surface 106 Conductor coating surface 110 substrate 112 board body 114 slot pattern 116 power feeding slot pattern 120 conductor film

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29L 31:34 B29L 31:34 C08L 45:00 C08L 45:00 F term (reference) 4F071 AA14 AA39 AA80 AA83 AF10 AF43 AF54 AH12 BA01 BB05 BC07 4F206 AA03 AD18 AH41 JA07 JF01 JL02 4J100 AR09 AR11 CA01 CA03 DA22 DA36 DA37 JA43 5J045 AB08 AB09 DA05 EA07 NA03 NA07

Claims (6)

[Claims] 1. A coefficient of thermal expansion of 7 with a water absorption of 0.01% or less.
50 GH consisting of an amorphous synthetic resin at x10 ⁻⁵ or less
Dielectric resin material that can be used for circuit members that use radio waves of z or higher. 2. The dielectric resin material according to claim 1, which has a dimethanonaphthalene structure in at least the molecule. 3. The induction tangent at 50 GHz is 2.0 ×
The dielectric resin material according to claim 1, which is 10 ^-4 or less. 4. The induction tangent at 50 GHz is 1.8 ×
The dielectric resin material according to claim 1, which is 10 ^-4 or less. 5. The dielectric resin material according to claim 1, wherein the dielectric resin material is an amorphous polyolefin. 6. A circuit member formed by injection molding using the dielectric resin material according to any one of claims 1 to 5.