JPH10163740A - Plane antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a plane antenna reduced in the number of parts, small in size, light in weight and low in cost. SOLUTION: This antenna 20 is provided with an antenna element 25 of antenna pattern arranged on the surface of top cover 23 and a ground conductor 26 of ground pattern arranged on the inner surface of this top cover 23, the antenna element 25 is connected through a hole opened on the top cover by wiring connected to any terminal or circuit element on a circuit board 22 and the ground conductor 26 is connected with any terminal or circuit element on the circuit board 22 as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar antenna, for example, a planar antenna used in a GPS (Global Positioning System).

[0002]

2. Description of the Related Art As is well known, a planar antenna used for a GPS is for receiving radio waves from a GPS artificial satellite. As shown in FIG. An antenna body 14 includes a circuit board 13 on which an element 11 and a circuit element 13a attached thereto are mounted. The antenna body 14 is housed in a resin case 16 for waterproofing and dustproofing, and is mounted on a roof panel of an automobile or when driving. It is installed and used at an appropriate place on the dashboard in front of the seat. In this case, the resin case 16 to be injection-molded includes a bottom cover 16a having a permanent magnet fixed thereto on the bottom surface. After the antenna body 14 is assembled into the bottom cover 16a, the upper surface of the bottom cover 16a is made of resin. Is configured to be covered by the top cover 16b.

[0003]

However, in such a configuration, since the number of parts is large, the number of assembling steps is also increased, which is an obstacle to simplifying the assembling steps and reducing the cost.

[0004]

In order to solve such a problem, an antenna pattern constituting an antenna element is arranged on an upper surface of a top cover.

[0005] With this configuration, the number of parts can be reduced as compared with the related art, and the number of assembly steps can be simplified to obtain a low-cost planar antenna.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the basic structure of the present invention. In FIG. 1, a planar antenna 20 has a bottom cover 21 in which a magnet (not shown) is installed, and is mounted on the bottom cover 21. A circuit board 22 on which a circuit element 22a is mounted; and a resin top cover 23 disposed so as to cover the circuit board 22 mounted on the bottom cover 21. Is arranged.

The top cover 23 is formed in a dome shape, for example, a radome made of a high frequency compatible dielectric composite material such as Terawave (trade name of Otsuka Chemical Co., Ltd.). An antenna element 25 of a patch pattern, that is, an antenna pattern is arranged, and a ground conductor 26 of a ground pattern is arranged on the inner surface. Then, the patch pattern antenna element 25 arranged on the outer upper surface of the top cover 23 is drawn in through the antenna pin 30 arranged in the through hole formed in the top cover 23, and is inserted through the flexible cable 31. It is connected to a predetermined portion on the circuit board 22, for example, a terminal on the circuit board 22 or one of the circuit elements 22a. A ground conductor 26, which is a ground pattern disposed on the inner surface of the top cover 23, is also provided at a predetermined location on the circuit board 22 via the flexible cable 32, for example, a terminal or a circuit element 2 on the circuit board 22.
2a. In addition, the bottom cover 21
And the top cover 23 are combined to form a resin cover.

In this case, the antenna element 25 and the ground conductor 26 are formed by, for example, attaching copper to the surface of the top cover 23 by a known plating method.

With this configuration, the top cover 23
Since the antenna element 25 of the patch pattern is arranged on the upper surface of the device, the number of components can be reduced as compared with the conventional case, the number of assembly steps can be simplified, and a low-cost planar antenna can be obtained.

Further, according to this structure, the exterior and the antenna element can be shared, so that the size and weight can be reduced. Also,
Since such a configuration can be molded with a general mold, an antenna element having an exterior of any shape can be manufactured. In addition, since the antenna element is arranged on the surface of the top cover, which is a resin case, the antenna pattern of the antenna element can be enlarged, the installation area can be widened, and the sensitivity can be increased.

FIG. 2 shows another embodiment of the present invention. The difference from FIG. 1 is that a patch pattern antenna element formed on an upper surface of a top cover 23 and a ground pattern formed on an inner surface are provided. If the surface of the ground conductor is coated with the coating layers 41 and 42 by using the requisite material, the rust of the patch pattern antenna element 25 and the ground conductor 26 of the ground pattern can be prevented. In addition, since this coating can also use the conventional coating method as it is, it is possible to freely coat according to the design. Further, by providing such a coating, the weather resistance of the planar antenna can be improved. Further, when the antenna element 25 and the ground conductor 26 are formed by a plating method, they can be protected mechanically and chemically.

The planar antenna specified by the present invention is not limited to the GPS, but can be applied to an array antenna or other complex antennas.

[0013]

As described above, when the planar antenna according to the present invention is used, the exterior and the antenna element can be shared, so that the size and weight can be reduced. In addition, since such a configuration can be molded by a general mold, an antenna element having an external shape of an arbitrary shape can be manufactured. Further, since the antenna element is arranged on the surface of the resin case, the range of the installation place is widened, and the sensitivity can be increased. Further, the number of components can be reduced as compared with the conventional case, and the number of assembly steps can be simplified to obtain a low-cost planar antenna. Also, if a coating layer is formed on the surface of the top cover that constitutes the resin case, mechanical and electrical protection of the antenna element and the ground conductor can be provided.When these are formed of a metal such as copper, Rust can be prevented and this coating can use the conventional coating method as it is,
You can freely adjust the coating according to the design. Further, with such a coating, the weather resistance of the planar antenna can be improved. When the antenna element and the ground conductor are formed by plating, the coating layer can provide chemical protection in addition to the above-described electrical and mechanical protection.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a planar antenna according to the present invention.

FIG. 2 is a configuration diagram showing an embodiment of the pond of FIG. 1;

FIG. 3 is a diagram showing a basic configuration of a conventional planar antenna.

[Explanation of symbols]

 10, 20 Planar antenna 11, 25 Antenna element 13, 22 Circuit board 13a, 22a Circuit element 14 Antenna body 16 Resin case 16a, 21 Bottom cover 16b, 23 Top cover 26 Ground conductor 30 Connection pin 31, 32 Flexible cable 41, 42 Coating layer

Claims (3)

[Claims] 1. A planar antenna having a top cover for covering a circuit board on which a circuit element disposed on a bottom cover is mounted, wherein: an antenna element having an antenna pattern disposed on a surface of the top cover; And a ground conductor of a ground pattern disposed on the inner surface of the antenna, wherein the antenna element is connected to a terminal on the circuit board or a wiring connected to the circuit element via a through hole formed in a top cover, and A planar antenna, wherein a ground conductor of the pattern is also connected to a terminal or a circuit element on the circuit board. 2. The planar antenna according to claim 1, further comprising a coating layer that covers an antenna pattern of the antenna element disposed on a surface of the top cover. 3. The planar antenna according to claim 1, further comprising a coating layer covering a ground conductor of a ground pattern disposed on an inner surface of the top cover.