JP3181032B2 - Portable radio - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable wireless device such as a digital cellular phone having a built-in planar antenna, and more particularly to a space saving of a built-in antenna structure.

[0002]

2. Description of the Related Art Conventionally, planar antennas have been widely used as built-in antennas for digital cellular phones because of their advantages of small size and high gain. The built-in antennas of these mobile phones are structured to be fixed directly on a circuit board.

[0003] In recent years, the mobile phone market has rapidly spread, and has been reduced in size to a size that can be stored in a pocket. Accordingly, the occupied space of the built-in antenna mounted on the mobile phone is also required to be reduced.

[0004] However, as the size of mobile phones becomes smaller, it becomes difficult to secure a space for a built-in antenna. This is because, when the dimensions of the housing became smaller, the circuit composed of a plurality of substrates became one.
A circuit is constituted by a single board, and the size of the circuit board itself is reduced. Therefore, electronic circuits are densely mounted on the circuit board over the entire board area. For this reason, the space for mounting the built-in antenna on the substrate is compressed, and the antenna must be configured with a small size. Generally, a small-sized antenna may cause a deterioration in gain, and may degrade the performance of a mobile phone. However, there is a dilemma that the electronic circuit cannot be accommodated in the housing when the size of the built-in antenna is increased.

[0005]

According to the present invention, in order to solve the above-mentioned problems and minimize the area occupied by the board of the built-in antenna without deteriorating the gain, the radiating element of the built-in antenna is fixed to the inner wall of the housing. The radiating element and the feeder circuit on the board have a conductor that can be electrically connected to each other, thereby obtaining a high gain internal antenna with a small circuit board occupying space.

[0006]

Embodiment 1 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side cross-sectional view of a housing of a portable wireless device of the present invention. In FIG.
The lower side of the paper is the front of the housing, 1 is a resin rear case which is the back of the case, 2 is the front case which is the front of the case, and 3 is a flat sheet made of thin sheet metal. An antenna radiating element. 4 is a power supply terminal part, 5 is a contact part, 6 is a circuit board, 7 is LC
D, 8 is a shield case for electromagnetically shielding, 9 is an RF circuit, 10 is a telescopic transmission / reception antenna that can be housed or extended, and 11 is for determining the position of the antenna radiating element 3. Reference numeral 12 denotes a double-sided tape for fixing the antenna element 3 to the inner wall of the rear case 1;
Is a digital circuit component, and 15 is a replaceable battery.

The antenna radiating element 3 is formed of a thin sheet metal (about 0.1 mm) made of a material such as phosphor bronze, and resonates in a reception band so as to receive a transmission radio wave from a base station. A 放射 λ (wavelength) non-contact antenna is constituted by a radiating element having a shape having an electrical length of １ ／ wavelength. Several holes are formed in the antenna radiating element 3, and the positioning of the antenna radiating element 3 is performed by fitting the positioning projections 11 of the rear case 1 into the holes when assembling the wireless device.

A slightly larger power supply land 13 on the circuit board 6 is connected to a receiving circuit (not shown) via a power supply circuit and a matching circuit (not shown). The power supply terminal portion 4 is made of a material that can be electrically conducted, and is soldered to the power supply land 13. The contact portion 5 has elasticity, and when the rear case 1 is attached to the circuit board 6 at the time of assembling the wireless device, the contact portion 5 comes into contact with an appropriate position of the antenna radiating element 3 with pressure to maintain electrical conduction.
This is for assembling and removing the rear case 1 without difficulty.

In such a configuration, the antenna radiating element 3 fixed to the inner wall of the rear case 1 resonates with the ground (the inner layer is also possible) on the circuit board 6 therebelow, and the reception is performed. The supplied power enters the receiving circuit from the antenna radiating element 3 through the feed terminal 4, feed land 13, and feed line.

As can be seen from the above, in the area occupied by the built-in antenna composed of the antenna radiating element 3 on the circuit board 6, the antenna radiating element 3 is not directly disposed on the circuit board 6 but along the inner wall of the rear case 1. Therefore, only the feed terminal 4 of the circuit board 6 relates to the built-in antenna, and the area occupied by the built-in antenna occupying the circuit board 6 is extremely small. Since a space corresponding to the space is vacant, if the component is short, it can be arranged on the circuit board 6 directly below the antenna radiating element 3 like the digital circuit component 14.

Since the antenna radiating element 3 uses the inner wall of the rear case 1, there is no space restriction. Therefore, the antenna radiating element 3 can be made large in size, so that the gain can be improved.

The following points also have a favorable effect on the improvement of the gain. The gain tends to increase as the height of the radiating element from the ground increases. However, according to the present invention, since the gap between the antenna radiating element 3 and the rear case 2 is eliminated, the gain from the circuit board 6 (ground) increases. The height of the antenna radiating element 3 becomes the maximum height that can be realized by the portable wireless device, and the gain can be greatly improved. Further, in the present invention, since a thin sheet metal is used for the antenna radiating element 3, there is no deterioration in gain due to dielectric loss.

Regarding the variation, the antenna radiating element 3
Since a sheet metal is used, the outer shape can be formed with high accuracy, and thus, variation can be suppressed.

The rear case 1 of the antenna radiating element 3
In the above-described example, the positioning projection 11 is provided on the rear case 1 and the antenna radiating element 3 is provided with a hole corresponding to the positioning projection 11 for positioning. The rear case 1 may be provided with a guide means such as a line or a groove so as to correspond to the outer shape of the antenna radiating element 3.

The power supply terminal 4 is connected to the antenna radiating element 3.
The conductor may have any shape as long as it can be electrically connected to the power supply land 13 and may be a spring or a plate-like spring.

Finally, the antenna radiating element 3 is fixed to the inner wall of the rear case 1 with a strong double-sided tape 12 because the antenna radiating element 3 is made of a thin sheet metal and light in weight. Instead, they may be bonded with an adhesive or the like, or the positioning protrusions 11 may be melted by heat and pushed to increase the size of the protruding portion and fixed.

As an example, in an example in which the present embodiment is used for a digital mobile phone in the 800 MHz band, the occupied area on the circuit board 6 is 5 mm × 4 mm (length × width) of the power supply terminal portion 4.
And the space becomes much smaller than the conventional space, but the size of the antenna radiating element itself is 24 mm × 24 mm × 7 mm (length × width × width) because the inner wall of the rear case is used.
(Height from the ground) and the size is not limited as in the conventional method, so that it can be made large.

[0018]

Second Embodiment FIG. 2 shows a second embodiment of the present invention. The same parts as those in FIG. 1 of the first embodiment are denoted by the same reference numerals, and the same description is omitted. As can be seen from FIG.
The difference from the above is the structure of the power supply terminal portion 4, which is similar in that a high gain can be obtained. First Embodiment In the case of FIG. 1, a holder for holding the power supply terminal portion 4 so that the power supply terminal portion 4 and the antenna radiating element 3 can come into contact with each other at the time of assembly is required in consideration of mass productivity. Naturally, the holder occupies a little area on the circuit board 6.

In order to improve this, in the second embodiment,
A part of a thin sheet metal forming the antenna radiating element 3 is subjected to a bending process to integrally form the feeding terminal portion 4. The tip of the power supply terminal portion 4 is provided with a bent contact portion 5. When the circuit board 6 is attached to the rear case 1 at the time of assembling the telephone, the contact portions 5 elastically contact the power supply lands 13 of the circuit board 6 with pressure to electrically connect to the circuits on the circuit board 6.

As described above, the feeding terminal portion 4 may be formed by processing a thin sheet metal. If the feeding terminal 4 is formed by bending a part of the antenna radiating element 3 formed of a thin flat sheet metal. Can be integrated. This way, you can make the same material,
Mass production is good because only bending work is required. When the power supply terminal 4 fixes the rear case 1 and the circuit board 6,
Any shape may be used as long as the antenna radiating element 3 and the feeding land 13 can be electrically connected and maintained.

Further, a feed terminal 4 is connected to the antenna radiating element 3.
Can be integrated by soldering. The feed terminal portion 4 may be a conductor of any shape as long as the antenna radiating element 3 and the feed land 12 can be electrically connected, and may be a spring or a plate-like spring.

As an example, in the case where the present embodiment is used for an 800 MHz band digital cellular phone, the occupied area on the circuit board 6 relating to the built-in antenna is 6 mm × 3 mm (length × length)
Only the power supply land 13 in the side) and the circuit board 6
Since there is no component related to the antenna radiating element 3 disposed at the same time, the area occupied by the circuit board can be minimized. The occupied area of the power supply land 13 can be smaller in the second embodiment than in the first embodiment.

As described above, for the built-in antenna, the circuit board 6 needs only the occupied area of the power supply land, and there is no need to dispose any other components related to the built-in antenna on the circuit board 6. This is effective for downsizing the machine.

[0024]

As described above, according to the present invention, it is possible to realize a high gain built-in antenna with a small space occupied by a circuit board in a portable wireless device. Moreover, by disposing the built-in antenna on the inner wall of the casing of the wireless device, other components can be placed in the space of the circuit board vacated immediately below the built-in antenna, so that the circuit board can be downsized, that is, the portable wireless device can be easily downsized.

[Brief description of the drawings]

FIG. 1 is a side cross-sectional view of a portable wireless device according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of a portable wireless device according to a second embodiment of the present invention.

[Explanation of symbols]

1: rear case 2: front case 3: antenna radiating element 4: feeding terminal part 5: contact part 6: circuit board
7: LCD 8: Shield case 9: RF circuit 10: Transmission / reception antenna 11: Projection 12: Double-sided tape 13: Power supply land 14: Digital circuit parts 15: Battery

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B 1/38 H01Q 1/24 H04M 1/02

Claims (3)

(57) [Claims] An antenna radiating element formed of a thin sheet metal, means for fixing the antenna radiating element to an inner wall of a housing, a circuit board, and when the circuit board is mounted on the housing,
A portable wireless device comprising: an antenna radiating element fixed to an inner wall of a housing; and a power supply terminal for electrically connecting a circuit on a circuit board. 2. The power supply terminal according to claim 1, wherein the power supply terminal is fixed on a circuit board in advance, and when the housing and the circuit board are mounted, the power supply terminal is in contact with the antenna radiating element fixed on the inner wall of the housing. The portable wireless device according to claim 1. 3. The power supply terminal is formed integrally with the antenna radiating element in advance, and when the housing and the circuit board are attached, the power supply terminal makes a biasing contact with a power supply land on the circuit board. The portable wireless device according to claim 1.