JPH09284023A - Radio wave equipment antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unnecessitate thermal press-fitting process, to eliminate restriction as against a mainbody side print substrate wiring and to contribute to economically, a production stop and the miniaturization of a device by holding and fixing the tip end part of a U-shaped bent part between an antenna element and a bottom board at a prescribed interval. SOLUTION: A whole conductive plate constituting the antenna element 1 is bent to be a U-shape, the U-shaped tip end part is bent to be the U-shape and the part is fixed by a resin-made spacer 2. The antenna element 1 and the bottom board 3 are formed by a same material and by bending in sheet press process. Since the interval between the bottom board and the element 1 is decided by the precision of a metal pattern used in press, precision is drastically high. Moreover, the tip end part of the bent element 1 is fixed by the spacer 2 by resin formation so as to decide distance between the element 1 and the bottom board 3 so that the variance of tuning frequencies caused by variance in the interval are extremely reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a built-in antenna for radio equipment.

[0002]

2. Description of the Related Art In a portable wireless device such as a portable telephone, the size and weight of the housing are being reduced to make it easier to carry, and the antenna can be inserted / pulled out into the case. Not only antennas, but antennas that can be built into the housing have been improved and put into practical use. Especially,
In the case of a diversity antenna that is effective against fading, a built-in receiving antenna is indispensable in addition to a whip antenna for both transmission and reception.

FIG. 4 is a structural example of a typical built-in antenna used in a conventional portable telephone, which is a structural example of a plate-shaped inverted F antenna dedicated to reception. (A) is a plan view,
(B) is a front view, (C), (D) is a side view. In the figure, 1 is an antenna element, 2 is a spacer, 4 is a ground terminal, 5 is a power supply terminal, 6 is a protrusion, and 7 is a positioning guide.

The antenna element 1 is constructed by providing one or more ground terminals 4 and power supply terminals 5 on a conductor plate bent in an inverted F shape, and sandwiching a spacer 2 made of a plastic resin molded product. , Soldered on the printed circuit board of the main unit. At this time, the antenna element 1
In order to keep the distance between the main body side printed circuit board and the main body side printed circuit board constant, the element side protrusion 6 of the spacer 2 is thermocompression bonded. In addition, the printed board side projection 7 of the spacer 2 is used as a guide for positioning.

Since the resonance frequency of the antenna having such a structure is determined by the longitudinal dimension of the element 1 and the relative permittivity between the element 1 and the printed circuit board,
It is important to control the dimension of the spacer 2 in the thickness direction, and thermocompression bonding of the spacer 2 and the element 1 is indispensable.
The management of the mechanical dimensions of the element 1 and the spacer 2 is perfect as long as the element 1 is a sheet metal mold processing, and the spacer 2 is a product made of resin and molded by the mold, and there is no concern. In addition, since the cost is produced by a method that is excellent in mass productivity, it is extremely economical at around several tens of yen.

[0006]

However, the first difficulty of this method is that it cannot be flowed to a general surface mounting line because there is a thermocompression bonding step in addition to the soldering step when mounting. is there. With the rapid spread of mobile phones, there is a strong demand for economic efficiency, and cost reduction is required by improving processes.

The second difficulty is that the main body side printed circuit board surface facing the element 1 must be the entire ground conductor surface (solid ground surface). This imposes restrictions on the wiring of the printed circuit board and the layout of parts, complicates the design, and requires the use of expensive multilayer boards to reduce the size, which shortens the development period. It is an issue that must be improved in order to put it on the trend of economicization.

An object of the present invention is to eliminate the thermocompression bonding process, which is a drawback of the prior art, and to eliminate the restrictions on the printed wiring of the main body side, thereby contributing to economic efficiency, yield improvement, and device miniaturization. To provide an antenna for use.

[0009]

According to the present invention, the entire conductor plate constituting the antenna element 1 is bent into a U shape as shown in FIG. Of the antenna element and the ground plane, which is remarkable for determining the tuning frequency, by making the U-shaped front end part bend further inward into a U-shape and fixing the part by the resin spacer 2. Has a structure that keeps constant. With this structure, the thermocompression bonding step in the manufacturing line, which has been conventionally required, is eliminated, and the restriction due to the solid ground of the main body side printed circuit board is eliminated.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the antenna element 1 and the base plate 3 are made of the same material and are formed by bending a sheet metal pressing process. Therefore, the distance between the base plate 3 and the element 1 is determined by the precision of the die used for the press, and therefore the precision is extremely high, and the bent tip of the element 1 is fixed by the spacer 2 formed by resin molding. Since the distance between 1 and the ground plane 3 is determined, the variation of the tuning frequency caused by the variation of this interval is extremely small.

Therefore, even in mass production, a stable tuning frequency can be maintained and high productivity can be maintained. In addition, by forming the base plate portion that was previously dependent on the main body side printed circuit board by itself, the degree of freedom in wiring of the main body side printed circuit board part is increased, there is no restriction on the arrangement of parts, and the development period is significantly It can be shortened and contribute to realization of miniaturization.

[0012]

FIG. 1 shows a first embodiment of the present invention. (A)
Is a plan view, (B) is a front view, (C) is a side view, and (D) is a sectional view taken along line AA of (A). 2 is a perspective view thereof. In these figures, 1 is an antenna element, 2 is a spacer, 3 is a ground plane, 4 is a ground terminal, 5 is a feeding terminal, and 7 is a positioning guide.

As for the antenna element 1 and the ground plane 3, one conductor plate is bent into a U-shape by press-molding sheet metal,
In addition, the tip portion is also bent inward in a U shape.
The tip end of the element 1 and the base plate 3 are kept at a predetermined distance by the spacer 2 formed by resin molding. The structure of the spacer 2 and the tip of the bent portion of the element is as shown in FIG. That is, the dimensions of the intervals a, b, and c of the tip bent portion are
Is determined by the dimensional accuracy of.

As described above, since the spacer 2 is made by molding a resin mold, its dimensional accuracy is extremely high. Therefore, the antenna tuning frequency according to this structure has a very small deviation from the set value because all the factors that cause variations depend on the mold. Therefore, the antenna according to the present structure has an advantage that the thermocompression bonding process of the conventional example is not necessary, the wiring of the printed circuit board to be mounted is not restricted, and the same performance as in the conventional case can be obtained.

As shown in the perspective view of the first embodiment shown in FIG. 2, it can be seen that the power feeding terminal portion 5 and the ground terminal portion 4 are reasonably processed by the sheet metal pressing process.

FIG. 3 is a perspective view showing a second embodiment of the present invention. Reference numerals are the same as those in FIGS. 1 and 2. In this example, the connecting portion between the element 1 and the ground plate 3 is processed to be narrower than the width of the element 1 in order to tune to a frequency lower than the tuning frequency determined by the longitudinal dimension of the element 1. This makes it possible to achieve further miniaturization.

[0017]

According to the present invention, the thermocompression bonding process can be eliminated with the same number of parts as the conventional example, and the mounting process can be performed on the main body side printed circuit board only by the manufacturing process including the general flow work. The economy can be realized. Furthermore, since the factor that determines the frequency depends on the mold, not on the printed circuit board on the main body side, variations in the tuning frequency are small, and the characteristic yield can be improved. Further, the wiring on the printed circuit board surface of the element mounting portion, which has been conventionally restricted by the whole-surface ground electrode, becomes free, which can contribute to downsizing of the device itself.

[Brief description of drawings]

FIG. 1 is a structural diagram showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a first embodiment of the present invention.

FIG. 3 is a perspective view showing a second embodiment of the present invention.

FIG. 4 is a structural example diagram of a conventional internal antenna.

[Explanation of symbols]

 1 Antenna Element 2 Spacer 3 Ground Plate 4 Grounding Terminal 5 Power Supply Terminal 6 Projection 7 Positioning Guide

Claims (2)

[Claims] 1. A plate-shaped antenna mounted in a housing of a wireless device, wherein an antenna element and a ground plate arranged in parallel with the antenna element are formed by bending the same conductor plate into a U-shape. Moreover, both of the tip portions are integrally molded by being bent inward in a U-shape, and the tip portion of the U-shaped portion of the tip portion is
An antenna for a radio device, comprising a resin spacer that holds and fixes the antenna element and the base plate at a predetermined interval. 2. The antenna for a radio device according to claim 1, wherein a width of a bent portion between the antenna element and the ground plane is narrower than a width of the antenna element and the ground plane.