JP2005094068A - Resin-made dielectric antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin-made dielectric antenna for providing a high dielectric constant and a low dielectric dissipation factor, capable of attaining miniaturization and being easily formed, even if the antenna has a complicated shape. <P>SOLUTION: The resin-made dielectric antenna is provided, the dielectric part 1 of which is formed by injection molding applied to a composite material comprising a synthetic resin and dielectric ceramics. The composite material is a material to which the injection molding is applicable, wherein the dielectric constant is 15 or larger at a frequency region of 100 MHz or higher and the dielectric dissipation factor is 0.01 or smaller. The composite material contains 20 to 60 vol.% of the synthetic resin, with which 40 to 80 vol.% of at least one kind of dielectric ceramics whose specific dielectric constant is 50 or larger at the frequency region of 100 MHz or higher is blended. Dielectric ceramics powder is reformed so as not to lose the fluidity, even under a high packed state, for example, dielectric ceramics powder whose granularity distribution peaks are two or larger, or dielectric ceramics powder having two kinds or more average particle diameters. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a resinous dielectric antenna for an electronic component, for example, a resinous dielectric antenna that exhibits good dielectric properties and excellent moldability, is used in a high frequency band, and can be used for a high frequency communication device or the like.

With the remarkable spread of patch antennas used in cellular phones, cordless phones, RFID (identification technology using wireless communication), lens antennas such as radio telescopes and millimeter wave radars, and satellite communication devices, Higher frequency and further downsizing of communication devices are desired. By the way, two dielectric characteristics, that is, a relative dielectric constant and a dielectric loss tangent of an antenna substrate incorporated in a communication device, are greatly involved in increasing the frequency of signals and reducing the size of the communication device. The relative dielectric constant is a parameter that indicates the degree of polarization inside the dielectric. The higher the relative dielectric constant of the antenna substrate, the shorter the wavelength of the signal that propagates through the circuit formed on the substrate, and the higher the frequency of the signal. To do. Therefore, if the relative dielectric constant of the substrate can be set high, it is possible to increase the frequency, thereby shortening the circuit and reducing the size of the communication device. Dielectric loss tangent is a parameter that indicates the amount of signal that is propagated in the dielectric and is lost by being converted to heat. The lower the value, the less signal loss, the less energy consumed, and the smaller the battery, so communication The machine itself can be downsized, and in addition, it can be used continuously for a long time.
Some of these dielectric antennas are made of high dielectric ceramics, but ceramics are not suitable for complex shaped antennas because of their very poor workability. As an antenna having a complex shape, an antenna made of a resin composite material based on a resin material that can be injection-molded and blended with high dielectric ceramics has been proposed (for example, Patent Documents 1 to 6).

JP-A-5-1229 JP-A-8-51247 JP 2002-197923 A JP 2001-401046 A JP 2001-401047 A JP 2001-401048 A

Patent Document 1 proposes an antenna in which two or more kinds of resins having a low dielectric loss tangent are blended and high dielectric ceramics are blended. In this proposal, since two or more kinds of resins are blended, variations in dielectric characteristics due to separation at the interface and poor dispersion occur, and therefore it cannot be used as a stable antenna material.
In Patent Document 2, a fibrous inorganic filler is blended as a high dielectric ceramic. However, since it is fibrous, there is a concern about variations in the linear expansion coefficient due to anisotropy. In addition, when the fibrous filler is highly compounded, the fluidity is extremely deteriorated and injection molding becomes difficult, so that it is difficult to obtain an antenna having a high relative dielectric constant.
Patent Document 3 proposes application to a lens antenna with a composite dielectric molded product made of a dielectric inorganic filler and an organic polymer material. It defines the melt viscosity at the time of injection molding, is 170 Pa · S or higher at a shear rate of 1000 S ⁻¹ , and the ceramic composition is described as a range of 1 to 55 vol%. When the injection moldability is taken into account, if the amount of ceramics increases, the melt viscosity becomes too high, which is not practical. When the existing ceramic powder is blended, the melt viscosity increases at 40 vol% or more, and stable molding becomes difficult.
In Patent Documents 4 to 6, the ceramic content is 10 to 40% by volume, which is still insufficient when considering the miniaturization of the antenna due to the high dielectric constant.

The problems to be solved by the invention are summarized as follows.
1). High dielectric constant and low dielectric loss tangent.
2). It is suitable as an antenna having a complicated shape.
3). There is no variation in dielectric characteristics due to peeling or poor dispersion at the interface.
Four). Little variation in coefficient of linear expansion due to anisotropy.
Five). Even if the dielectric ceramics are highly blended, the fluidity is good and injection molding is possible.

  An object of the present invention is to provide a resin dielectric antenna that exhibits a high relative dielectric constant and a low dielectric loss tangent, can be miniaturized, and can be easily molded even in a complicated shape.

The resin dielectric antenna of the present invention is a composite material of a synthetic resin and a dielectric ceramic, and can be injection molded with a relative dielectric constant of 15 or more and a dielectric loss tangent of 0.01 or less in a frequency range of 100 MHz or more. It is composed of materials.
According to the resin dielectric antenna having this configuration, since the relative dielectric constant is as high as 15 or higher in the frequency range of 100 MHz or higher, the wavelength of the signal propagating through the circuit formed on the dielectric portion serving as the antenna substrate becomes short. The signal becomes high frequency. Therefore, it is possible to increase the frequency, thereby shortening the circuit and reducing the size of the communication device. In addition, since the dielectric loss tangent is as small as 0.01 or less in the frequency range of 100 MHz or more, signal loss is reduced, energy consumption is reduced, the battery can be downsized, and the communication device itself can be downsized. In addition, it can be used continuously for a long time. In addition, since a material that can be injection-molded is used, an antenna having a complicated shape can be obtained. If injection molding is used, for example, the circuit portion is made of copper foil, and insert molding can be performed to integrate the circuit and the antenna.
In the frequency range below 100 MHz, the wavelength is as long as about 3 m. For example, when the relative dielectric constant is about 15, the dimensions of the antenna become large even if a dielectric resin composite material is used. Therefore, the whole antenna cannot be reduced in size.

The resin dielectric antenna of the present invention comprises a material containing 20 to 60 vol% of a resin material and 40 to 80 vol% of at least one kind of dielectric ceramics having a relative dielectric constant of 20 or more in a frequency range of 100 MHz or higher. It is good as a thing. The dielectric constant of the dielectric ceramic is more preferably 50 or higher in a frequency range of 100 MHz or higher.
When the blend of dielectric ceramics having a relative dielectric constant of 20 or more is 40 to 80 vol%, a dielectric constant of 15 or more can be secured in the resin dielectric antenna, and injection molding is also possible. When the dielectric ceramic content is less than 40 vol%, a sufficient dielectric constant cannot be obtained, which is insufficient for miniaturization. On the other hand, if the blending of the dielectric ceramic exceeds 80 vol%, the fluidity is lowered and injection molding becomes difficult. The blending ratio of dielectric ceramics considering dielectric properties and injection moldability is more preferably 40 to 70 vol%. In order to perform injection molding with a dielectric ceramic composition of 40 to 80 vol%, it is difficult to use ordinary dielectric ceramic powder, and it is necessary to use dielectric ceramic with improved fluidity as follows.

The dielectric ceramic in the material is preferably modified so as not to impair the fluidity even under high filling.
A highly functional antenna can be obtained by blending a dielectric ceramic with improved fluidity into a resin that can be injection molded. By using a dielectric ceramic that has been modified so as not to impair the fluidity, a higher composition is possible than conventional dielectric ceramics, which contributes to the miniaturization of the antenna. Moreover, since injection molding is possible, it can be applied to an antenna having a complicated shape.
Examples of dielectric ceramics modified so as not to impair fluidity even under high filling include dielectric ceramic powders having two or more particle size distribution peaks and dielectric ceramics having two or more types of average particle diameters. Powder can be used. When there are two or more particle size distribution peaks, fluidity is improved because small particles are likely to enter a gap between adjacent relatively large particles. The same applies to the case of having two or more types of average particle sizes.
When the dielectric ceramic powder has one particle size distribution peak, injection molding is difficult or impossible when the blending amount is 40 vol% or more, but there are two or more particle size distribution peaks as described above. When the dielectric ceramic powder is used, injection molding is possible even when the dielectric ceramic powder content is in the range of 40 to 80 vol%. Even when a dielectric ceramic powder having a particle size distribution peak of 2 or more is used, injection molding is difficult when the blending amount exceeds 80 vol%. From the viewpoint of both injection moldability and dielectric characteristics, it is 40 to 70 vol%. The blending amount is more preferable.
The dielectric ceramic powder having two or more peaks in the particle size distribution and the dielectric ceramic powder having two or more kinds of average particle diameters are not limited to one kind of dielectric ceramic powder, and are different in material. Two or more types of dielectric ceramic powders may be used, and either the peak position of the particle size distribution or the average particle diameter of the dielectric ceramic powders of the respective materials may be different.

  For example, strontium titanate can be used as the dielectric ceramic to be blended with the resin dielectric antenna of the present invention, and calcium titanate can be used in addition to this. When these strontium titanates and calcium titanates are used, those having a relative dielectric constant of 50 or more in a frequency range of 100 MHz or more can be obtained.

  The resin dielectric antenna according to the present invention is a composite material mainly composed of a resin material, and is a material that can be injection-molded with a relative dielectric constant of 15 or more and a dielectric loss tangent of 0.01 or less in a frequency range of 100 MHz or more. Therefore, it has a high relative dielectric constant and a low dielectric loss tangent, can be miniaturized, and can be easily molded even if it has a complicated shape.

  A first embodiment of the present invention will be described with reference to FIG. This resinous dielectric antenna is applied to a planar antenna, and is provided with a conductor 2 on a dielectric portion 1 serving as an antenna substrate. The dielectric portion 1 is plate-shaped or film-shaped. The dielectric portion 1 may be thick, such as a thin one having a thickness of about 10 μm to a thickness of about 5 mm. The dielectric part 1 is manufactured by injection molding or the like. The conductor 2 is a metal foil such as a copper foil or a metal thin plate. The conductor 2 may be fixed to the dielectric part 1 by insert molding or the like at the time of injection molding of the dielectric part 1, or may be deposited on the molded dielectric part 1 by printing or vapor deposition. The conductor 2 has an arbitrary antenna pattern shape such as a loop shape. Terminal portions 2 a and 2 b are provided at the end of the conductor 2.

  The material of the dielectric part 1 is a composite material of synthetic resin and dielectric ceramics, and a material that can be injection molded with a relative dielectric constant of 15 or more and a dielectric loss tangent of 0.01 or less in a frequency range of 100 MHz or more. To do. The synthetic resin and the dielectric ceramic are both mixed as powder, a pellet is produced from the mixed powder, and the pellet is injection-molded to form a predetermined dielectric portion 1 shape.

  The synthetic resin used for the dielectric resin composite is not particularly limited, and various known resins can be used. For example, polyethylene, polypropylene, chlorinated polyolefin, 5-methylpentene resin, cyclic polyolefin, polystyrene, modified polystyrene, syndiotactic polystyrene, polyphenylene ether, ABS resin, polyamide, acrylic resin, methacrylic resin, polyacetal, polycarbonate, thermoplastic polyimide , Polyetherimide, polyamideimide, ionomer resin, polyether ketone, polyether nitrile, polyphenylene sulfide, polysulfone, polyester, aromatic polyester, liquid crystal polyester, polyethylene terephthalate, polybutylene terephthalate, heat-melting fluororesin, etc. is there. Among these, those having a low dielectric loss tangent in a high frequency region are preferable. Specifically, cyclic polyolefin, polyetherimide, polyphenylene ether, syndioctacic polystyrene, 5-methylpentene resin, polyphenylene sulfide, liquid crystal polyester, heat melting Can be mentioned.

The dielectric ceramic used for the dielectric resin composite material substantially determines the dielectric constant of the composite resin material, and among the dielectric ceramics, a high dielectric ceramic having a high dielectric constant is preferable. Examples of the dielectric ceramic powder usable in the present invention include IIa, IVa, IIIb, and IVb group oxides, carbonates, phosphates, silicates, and complex oxides including IIa, IVa, IIIb, and IVb groups. At least one selected from the above is preferable. Specifically, TiO ₂ , CaTiO ₃ , MgTiO ₃ , Al ₂ O ₃ , BaTiO ₃ , SrTiO ₃ , CaCO ₃ , Ca ₂ P ₂ O ₇ , SiO ₂ , Mg ₂ SiO ₄ , Ca ₂ MgSi ₂ O _{7 and the} like. The dielectric ceramic powder preferably has a relative dielectric constant of 20 or higher in a frequency range of 100 MHz or higher, and more preferably has a relative dielectric constant of 50 or higher. The condition that the relative dielectric constant is 20 or more corresponds to all general dielectric ceramics. Moreover, according to each powder enumerated above, the thing with a dielectric constant of 50 or more is obtained.
The particle diameter of the ceramic powder is preferably about 0.01 μm to 100 μm. When it is smaller than 0.01 μm, it is difficult to handle, which is not preferable. If it is larger than 100 μm, it is not preferable because it may cause variation in dielectric characteristics in the molded body. A more practical range is about 0.1 μm to 20 μm. These dielectric ceramic powders give a crystal distortion of 0.01 to 0.25%. When the crystal strain is smaller than 0.01%, there is little effect in improving the fluidity of the molten resin. A crystal strain larger than 0.25% is not preferable because the dielectric characteristics deteriorate.

The dielectric ceramic powder is preferably modified so as not to impair the fluidity even under high filling. For example, dielectric ceramic powder having two or more particle size distribution peaks may be used, which is effective for improving fluidity. This is because when there are two or more peaks in the particle size distribution, fluidity is improved because small particles easily enter the gap between adjacent relatively large particles in the molten resin. . Also, using dielectric ceramic powder having two or more types of average particle diameters is effective for improving fluidity as described above. The dielectric ceramic powder having two or more peaks in the particle size distribution and the dielectric ceramic powder having two or more kinds of average particle diameters are not limited to one kind of dielectric ceramic powder, and are different in material. Two or more types of dielectric ceramic powders may be used, and either the peak position of the particle size distribution or the average particle diameter of the dielectric ceramic powders of the respective materials may be different.
For dielectric ceramic powders having two or more particle size distribution peaks or two or more types of average particle sizes, the firing conditions (for example, temperature and time) and the grinding method are selected in the process of obtaining the dielectric ceramic powder. Alternatively, it can be obtained by adjusting the particle size distribution with a sieve. By changing the firing conditions and the like, the particle size distribution and crystal distortion change.
The blending ratio of the dielectric ceramic is preferably 40 to 80 vol%, and the blending ratio considering the dielectric characteristics and injection moldability is more preferably 40 to 70 vol%.

  The frequency range in which the resin dielectric antenna is used is preferably 100 MHz to 120 GHz, more preferably 1 to 100 GHz, and still more preferably 3 to 80 GHz. The dielectric constant of the dielectric resin composite material used as the antenna material is preferably 15 to 70 in consideration of dielectric characteristics and injection moldability. The relative dielectric constant considering dielectric properties and injection moldability is more preferably 20-60.

According to the resin dielectric antenna having this configuration, since the relative dielectric constant of the dielectric portion 1 serving as the antenna substrate is as high as 15 or more in a frequency range of 100 MHz or higher, a circuit using the conductor 2 formed on the dielectric portion 1 is provided. The wavelength of the propagated signal becomes shorter and the signal becomes higher in frequency. Therefore, it is possible to increase the frequency, thereby shortening the circuit and reducing the size of the communication device. Further, since the dielectric loss tangent is as small as 0.01 or less in a frequency range of 100 MHz or higher, signal loss is reduced, energy consumption is reduced, and the battery can be downsized. As a result, the communication device itself can be downsized, and in addition, it can be used continuously for a long time. In addition, since a material that can be injection-molded is used, an antenna having a complicated shape can be obtained. If injection molding is used, it is possible to integrate the circuit and the antenna substrate by manufacturing the circuit portion of the conductor 2 with copper foil and insert molding as described above.
Moreover, a highly functional antenna can be obtained by mix | blending the dielectric ceramic which improved fluidity | liquidity with resin which can be injection-molded as mentioned above. As a result, a higher blending is possible compared to conventional dielectric ceramics, which can contribute to miniaturization of the antenna.
The specific permittivity is set to 15 or more in detail for the following reason. A high relative dielectric constant means a high content of dielectric ceramics. The advantage in that case is a reduction in the coefficient of linear expansion. For example, taking PPS as an example, the linear expansion coefficient is 5 × 10 ⁻⁵ in the case of a resin alone, whereas the linear expansion coefficient is about 2 × 10 ^{−5 in} the case of a material having a relative dielectric constant of 15. It becomes. As described above, the effect of lowering the linear expansion coefficient has the advantage that the operating temperature range is widened, and when used in the low / high temperature range, the dimensional stability is good and the antenna accuracy can be improved. Further, when the relative permittivity is increased, the antenna can be reduced in size, and thus there is an advantage that the material cost to be used can be reduced.

Next, test examples of each example and comparative example will be described.
(Example)
Strontium titanate ceramic powder A based on polypropylene (PP) and polyphenylene sulfide (PPS) and subjected to high filling treatment (peak position of particle size distribution: peak 1) 1 μm, peak 2) 3.5 μm, A predetermined amount of average particle size: 1.5 μm, crystal strain: 0.08% was blended to produce pellets by biaxial mixing, and injection molding was performed using a 70 mm × 70 mm × 5 mm mold. The treatment for high packing is to have two peaks in the particle size distribution, and each peak is the above-mentioned peak 1) and peak 2). A test piece of 1.5 mm × 1.5 mm × 65 mm was cut from the injection molded body to prepare a test piece for measuring dielectric properties. The relative permittivity and dielectric loss tangent were measured by the cavity resonator method in the 1, 3, and 5 GHz bands. In addition, with respect to each injection-molded body, with reference to the relative dielectric constant of 5 GHz, the thickness of each material is an integral multiple of 1/2 of the effective wavelength at 20, 40, and 76 GHz (considering workability, it is 3 times). The dielectric properties were evaluated by the Fabry-Perot resonator method.

  Tables 1 and 2 show the composition and dielectric characteristics of each test piece, respectively. Moreover, the determination result of injection moldability is described together. The judgment results were shown as molding without problem: ◯, molding not possible due to poor fluidity: x.

  In the case of Examples 1 to 14, injection molding is possible without problems despite the high blending amount of ceramic powder of 40 to 80 vol%, the relative dielectric constant is as high as about 17 to 52, and the dielectric loss tangent is It is about 0.003 to 0.005 and shows excellent dielectric properties.

(Comparative example)
Strontium titanate ceramic powder A using polypropylene (PP) and polyphenylene sulfide (PPS) as base resins and subjected to the same high-filling treatment as above (peak position of particle size distribution: peak 1) 1 μm, peak 2) 3 0.5 μm, average particle size: 1.5 μm, crystal distortion: 0.08%), strontium titanate ceramic powder B not subjected to high filling treatment (peak position of particle size distribution: peak 1) 1 μm only, Biaxial mixing for each material containing a predetermined amount of average particle size: 1.5 μm, crystal strain: 0%) and fibrous barium strontium titanate (average fiber size: 0.3 μm, average fiber length: 8 μm) The pellet was manufactured by the above and injection molding was performed using a 70 mm × 70 mm × 5 mm mold. A test piece of 1.5 mm × 1.5 mm × 65 mm was cut from the injection molded body to prepare a test piece for measuring dielectric properties. The relative permittivity and dielectric loss tangent were measured by the cavity resonator method in the 1, 3, and 5 GHz bands. In addition, with respect to each injection-molded body, with reference to the relative dielectric constant of 5 GHz, the thickness of each material is an integral multiple of 1/2 of the effective wavelength at 20, 40, and 76 GHz (considering workability, it is 3 times). The dielectric properties were evaluated by the Fabry-Perot resonator method.

  Tables 3 and 4 show the composition and dielectric properties of each test piece, respectively. Table 3 also shows the determination results of injection moldability. The injection moldability is indicated by: No problem with molding: ◯, impossible molding due to poor fluidity: x.

In the case of Comparative Examples 1 and 6, the blending amount of the ceramic powder subjected to the high filling treatment is 30 vol%, and injection molding can be performed without any problem, but the relative dielectric constant is about 13, It is not preferable when downsizing is considered.
In the case of Comparative Examples 2 and 7, the blending amount of the ceramic powder subjected to the high filling treatment is 90 vol%, and the fluidity is poor and injection molding cannot be performed.
In the case of Comparative Examples 3 to 5 and 8 to 10, the blending amount of the ceramic powder not subjected to the high filling treatment is 50 to 80 vol%, and the fluidity is poor and injection molding cannot be performed.
In the case of Comparative Example 13, the blending amount of fibrous barium strontium titanate is 50 vol%, and injection molding can be performed without any problem. However, the relative dielectric constant is about 14, which is not preferable when considering miniaturization of the antenna. .
In Comparative Examples 14 and 15, the compounding amounts of fibrous barium strontium titanate are 60 and 80 vol%, respectively, and the fluidity is poor and injection molding cannot be performed.

  In addition, although the said embodiment demonstrated about the case where it applied to a planar antenna, this invention is applicable to a resin dielectric antenna of various types besides this. For example, the present invention can be applied to a resin dielectric antenna of each type shown in FIGS. 2 to 5 and a dome antenna (not shown). In any of the embodiments, the dielectric resin composite material in the first embodiment can be used, and the dielectric ceramic powder was modified so as not to impair the fluidity even under high filling as described above. For example, those using dielectric ceramic powder having two or more particle size distribution peaks as described above, or those using dielectric ceramic powder having two or more kinds of average particle diameters are preferable.

  FIG. 2 shows an example in which the present invention is applied to a patch antenna. The resin dielectric antenna includes a dielectric part 1 and radiation-side and installation-side conductors 2A and 2B provided on the front and back sides of the dielectric part 1. For example, a metal foil or a metal thin plate is used for each of the conductors 2A and 2B. The material of the dielectric part 1 is the same as that of the first embodiment.

FIG. 3 shows an example in which the present invention is applied to a housing integrated antenna. This resin dielectric antenna is composed of a dielectric part 1 which becomes a housing of an electronic device, and a conductor 2 integrated in the dielectric part 1 by insert molding or the like. The conductor 2 is made of copper foil or the like. The dielectric portion 1 may serve as the entire housing of the electronic device or may serve as a housing for the antenna unit portion in the electronic device. An electronic device to which the housing integrated antenna is applied is, for example, a portable electronic terminal such as a mobile phone or a personal computer, or a wireless communication card that is detachably attached to a slot of the portable electronic terminal.
When applied to such a housing-integrated antenna, the dielectric portion 1 has a complicated shape, and therefore the effect of facilitating injection molding by improving the fluidity of the dielectric resin composite material according to the present invention is more effective. It becomes.

  FIG. 4 shows an example in which the present invention is applied to a lens antenna. This resin dielectric antenna is composed of a dielectric portion 1 formed in a lens shape and an antenna element 3. A convergent lens such as a convex lens is used as the lens made of the dielectric portion 1. The dielectric portion 1 may be one in which a supporting frame portion (not shown) is integrally formed. The antenna element 3 is a primary radiator, a planar antenna, or the like, and is disposed at the focal point of a lens formed of the dielectric portion 1, for example. The antenna element 3 may be provided in contact with the lens formed of the dielectric portion 1. The shape of the lens formed of the dielectric portion 1 is not limited to the one-sided convex shape as shown in the figure, and may be a double-sided convex shape. Further, as shown in FIG. 5, the lens formed of the dielectric portion 1 may have a stepped shape in which a plurality of lens portions 1a, 1b,. The lens portions 1a, 1b,... At each stage are obtained by rounding the convex lens and shifting it in the thickness direction so that the focal points coincide. Increasing the number of steps can reduce the lens thickness. Furthermore, the dielectric part 1 may be planar because it is multistage. The material of the dielectric part 1 is the same as that of the first embodiment.

1 is a perspective view of a resin dielectric antenna according to a first embodiment of the present invention. It is the perspective view and sectional drawing of the resin-made dielectric antenna which concern on other embodiment of this invention. It is sectional drawing of the resin-made dielectric antenna which concerns on further another embodiment of this invention. It is sectional drawing of the resin-made dielectric antenna which concerns on further another embodiment of this invention. It is sectional drawing of the modification of the lens which consists of the dielectric material part.

Explanation of symbols

1 ... Dielectric part 2 ... Conductor

Claims (6)

  Resin dielectric antenna composed of a composite material of synthetic resin and dielectric ceramics, which is made of a material capable of injection molding showing a relative dielectric constant of 15 or more and a dielectric loss tangent of 0.01 or less in a frequency range of 100 MHz or more .   The resin dielectric antenna according to claim 1, wherein the dielectric antenna is made of a material containing 20 to 60 vol% of a synthetic resin and blended with 40 to 80 vol% of at least one dielectric ceramic having a relative dielectric constant of 20 or more in a frequency range of 100 MHz or more. .   3. A resinous dielectric antenna according to claim 1 or 2, wherein a dielectric ceramic modified so as not to impair fluidity even under high filling is blended.   4. The dielectric ceramic according to claim 3, wherein the dielectric ceramic modified so as not to impair the fluidity even under high filling is a dielectric ceramic powder having two or more particle size distribution peaks, or a dielectric having two or more types of average particle diameters. Resinous dielectric antenna, which is a conductive ceramic powder.   5. The resin dielectric antenna according to claim 1, wherein the dielectric ceramic is strontium titanate.   5. The resin dielectric antenna according to claim 1, wherein the dielectric ceramic is calcium titanate.

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