JPH06350323A - Antenna module - Google Patents

Abstract

PURPOSE:To provide an antenna modules whose characteristics differ without changing a metallic die by making a part of a resin of a resin including air bubbles and varying its air bubble containing rate. CONSTITUTION:The antenna module is formed by integrally provided an antenna element 2 and an earth pattern 3 to be surface of the resin forming 1 formed by molding a resin including uniformly infinite air bubbles to a predetermined shape. Since the resonance frequency of the module is inversely proportional to the dielectric constant of a material of the forming body 1 even in the case of the same shape and size, the module having a desired resonance frequency is obtained without changing the size by changing the dielectric constant through the adjustment of a blending ratio (air bubble contained rate) of the resin and the inorganic hollow packing material of the forming body 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small antenna module incorporated in a portable communication device or the like.

[0002]

2. Description of the Related Art Inverted F-type antennas and S-type antennas incorporated in mobile phones and the like have hitherto been manufactured by sheet metal technology. In order to secure the electrical characteristics (resonance frequency, bandwidth, gain, etc.) of these antennas, high dimensional accuracy is required not only in the external dimensions but also in the gap dimension between the antenna element and the ground. This has been extremely difficult to achieve.

To solve this problem, various structures have been proposed in the past, and one of them has been put into practical use as an antenna module as shown in FIG.
185003). This is one in which an antenna element 2 made of copper foil and an earth pattern 3 are integrally provided on the surface of a resin molded body 1 molded in a predetermined shape. Reference numeral 4 is a power supply terminal portion, and 5 is a loop forming portion.
This type is a type of inverted F-type antenna and is called a P-type antenna module.

[0004]

The antenna module having such a configuration obtains desired antenna characteristics depending on the shape and size of the resin molded body 1. Particularly, the resonance frequency of the antenna element 2 and the ground pattern 3 is different. Determined by distance. Therefore, when it becomes necessary to change the resonance frequency, it is necessary to change the dimensions of the resin molded body 1, and for that purpose, it is necessary to newly manufacture a mold for molding the resin molded body. When a new mold is manufactured, it is necessary to adjust the shape and size of the mold until the antenna module manufactured by the mold satisfies the required characteristics (resonance frequency, bandwidth, gain, etc.). . Therefore, the conventional antenna module of this type has a drawback that it takes a considerable amount of time and cost to obtain the required characteristics.

[0005]

The present invention provides an antenna module which solves the above problems.
The structure is such that, in an antenna module in which an antenna element made of a conductive layer and an earth pattern are integrally provided on the surface of a resin molded body molded in a predetermined shape, the resin molded body is made of resin containing bubbles. It is characterized by.

[0006]

By doing so, the permittivity between the antenna element and the ground pattern can be changed depending on the proportion of bubbles contained in the resin molded body, so that the size of the resin molded body is not changed, that is, the mold is changed. It is possible to obtain desired electrical characteristics without having to do so.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In this antenna module, an antenna element 2 and an earth pattern 3 are integrally provided on the surface of a resin molded body 1 obtained by molding a resin containing a myriad of bubbles uniformly into a predetermined shape. In addition, 4 is a power supply terminal part, 5 is a loop forming part, 6
Is a soldering part.

The resin molding 1 containing bubbles as described above is
It can be obtained by molding a thermosetting resin such as an epoxy resin or a thermoplastic resin such as polyphenylene sulfite or polyethylene terephthalate mixed with fused silica and an inorganic hollow filler (glass beads etc.). .

Incidentally, it is assumed that 50 parts by volume of an inorganic filler composed of fused silica and an inorganic hollow filler is mixed into a molding resin so that the shrinkage during molding is uniform. When the dielectric constant of a sheet molded by variously changing the volume part of the filler is measured, as shown in FIG. 2, as the mixing ratio of the inorganic hollow filler is increased (the number of bubbles is increased), the dielectric constant is increased. Tends to decline.

On the other hand, the resonance frequency of the antenna module shown in FIG. 1 is inversely proportional to the dielectric constant of the material of the resin molded body as shown in FIG. An antenna module having a desired resonance frequency can be obtained without changing the dimensions by adjusting the mixing ratio (bubble content) of the resin of the resin molded body and the inorganic hollow filler to change the dielectric constant.

In the above embodiment, the resin molded body containing bubbles was formed by mixing the inorganic hollow filler into the resin, but the means for forming the resin molded body containing bubbles is not limited to this. , For example, a method of forming bubbles by blowing a high-pressure gas into a molten resin at the time of molding, a method of molding a resin pellet impregnated with a volatile low-boiling solvent such as Freon 22 in advance, a resin pellet It is also possible to employ a so-called foam molding technique such as a method of molding a mixture of a chemical foaming agent such as baking soda and azodicarbonamide.

The resin molding 1 shown in FIG. 1 has a hollow portion 7 inside.
However, the resin molded body 1 may have a solid structure without a hollow portion, and in the case of forming a hollow portion, a resin is injected into a mold and then a gas is injected to open the hollow portion. It is also possible to employ the gas-assisted injection molding technique for forming.

The antenna element 2 and the ground pattern 3 in which the feeding terminal portion 4 and the loop forming portion 5 are formed in series are preferably made of a composite material of copper foil and a plastic film, but the feeding terminal portion and the loop forming portion are preferably formed. If a metal such as a strip, a rod, or a foil is attached later, the antenna element and the ground pattern can be formed by a conductive paint or plating.

Next, FIGS. 4 and 5 show another embodiment of the present invention. In this antenna module, the resin molded body 1 is divided into a central portion 1a and an outer peripheral portion 1b, and first, as shown in FIG. 4, the central portion 1a is formed of resin containing no air bubbles,
As shown in FIG. 5, the outer peripheral portion 1b is formed of resin containing bubbles. Since the electric current concentrates on the outer peripheral portion of the antenna element 2, if the outer peripheral portion 1b is made of a resin containing bubbles and the central portion 1a is made of a resin having no bubbles, the mechanical strength of the resin molded body 1 is improved. The permittivity can be changed effectively without loss.

The central portion 1a may be made of a resin containing no bubbles, but a resin containing some bubbles and having a smaller bubble content rate than the outer peripheral portion 1b. The difference in bubble content between the central portion 1a and the outer peripheral portion 1b may be determined by the balance between the dielectric constant and the mechanical strength of the resin molded body 1.

Next, FIGS. 6 to 8 show still another embodiment of the present invention. In this antenna module, a hollow portion 8 is formed inside both side wall portions of a resin molded body 1 by a gas assist injection molding technique. The size of the hollow portion 8 changes by adjusting the pressure of gas discharged from a gas nozzle provided at a position corresponding to the gas injection port 9 of the resin molded body 1 and the amount of resin injected into the mold. The antenna module having different characteristics can be obtained depending on the size of the hollow portion 8.

Next, FIG. 9 shows still another embodiment of the present invention. In this antenna module, two resin moldings 1A and 1B having the same shape and different bubble contents are formed adjacently on one earth pattern 3, and each resin molding 1A,
The antenna elements 2A and 2B are formed on 1B, respectively. The feeding terminal portions 4A and 4B of the antenna elements 2A and 2B are provided at symmetrical positions. In this way, the antenna modules having different characteristics can be obtained in a wider range by changing the difference in the bubble content rates of the resin molded products 1A and 1B.

[0018]

As described above, according to the present invention, since at least a part of the resin molding is made of resin containing bubbles, the characteristics can be changed without changing the mold by changing the bubble content. The antenna module can be obtained, and the weight of the antenna module can be reduced. Further, if the characteristics are the same, the antenna module can be made smaller than before.

[Brief description of drawings]

FIG. 1 is a sectional view showing an antenna module according to an embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a mixing ratio of an inorganic hollow filler to a resin and a dielectric constant.

FIG. 3 is a graph showing the relationship between the dielectric constant of the resin molding material and the resonance frequency of the antenna module.

FIG. 4 is a perspective view showing an intermediate stage of manufacturing an antenna module according to another embodiment of the present invention.

5 is a perspective view showing a completed state of the antenna module of FIG.

FIG. 6 is a perspective view showing an antenna module according to still another embodiment of the present invention.

7 is a cross-sectional view taken along the line AA of the antenna module of FIG.

8 is a cross-sectional view of the antenna module of FIG. 6 taken along the line BB.

FIG. 9 is a perspective view of an antenna module according to another embodiment of the present invention.

FIG. 10 is a perspective view showing a conventional antenna module.

[Explanation of symbols]

 1: Resin molded product 2: Antenna element 3: Earth pattern 4: Power supply terminal part 5: Loop forming part 6: Soldering part 7, 8: Hollow part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuyoshi Aoki 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Ken Maeda 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Inside Fujitsu Limited (72) Inventor Mitsuo Inagaki 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Inside Fujitsu Limited (72) Inventor Hiroshi Higashiguchi 1015 Kamedotaka, Nakahara-ku, Kawasaki-shi, Kanagawa Inside Fujitsu Limited

Claims (3)

[Claims] 1. An antenna module in which an antenna element made of a conductive layer and an earth pattern are integrally provided on the surface of a resin molded body molded in a predetermined shape, wherein the resin molded body is made of resin containing bubbles. Antenna module characterized by. 2. An antenna module in which an antenna element made of a conductive layer and an earth pattern are integrally provided on the surface of a resin molded body molded in a predetermined shape, wherein the resin molded body contains resin containing bubbles and bubbles. An antenna module characterized by being made of a resin not containing. 3. The antenna module according to claim 1, wherein the resin containing bubbles comprises a plurality of regions having different bubble contents.