JP2002141723A - Mount structure for antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mount structure for an antenna by which absorption of a radio wave by an enclosure or components or the like in inside the enclosure is prevented so as to avoid the antenna efficiency from being deteriorated even in the case of incorporating the antenna inside the enclosure of an electronic device such as a personal computer. SOLUTION: In the case of incorporating the antenna inside the enclosure of the electronic device, the emission face of the antenna 2 inside the enclosure 11 is outwardly directed, no material reflecting or absorbing a radio wave exists in the enclosure 11 in front of the emission face and a ground conductor of the antenna 2 or a ground conductor of a mount board (not shown) on which the antenna 2 is mounted is directly connected to a shield plate 13 and a metallic plate such as a metal-made frame existing in the enclosure 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Bluetooth (blue tooth), a LAN (local area network),
Or personal computers (hereinafter referred to as personal computers), PDAs (personal digital ass)
The present invention relates to a mounting structure of an antenna mounted on an electronic device such as an istant or personal data assistant), a mobile terminal, a mobile phone, and a home appliance. More specifically, the present invention relates to an antenna mounting structure capable of increasing transmission / reception sensitivity without lowering antenna efficiency due to absorption of radio waves in the housing when the antenna is built in the housing of the electronic device.

[0002]

2. Description of the Related Art Bluetooth is standardized as a next-generation short-range wireless technology, and wireless data transmission and reception are performed between personal computers, between personal computers and peripheral devices, between personal computers and mobile phones, between personal computers and home electric appliances, and the like. A method of operating the system is being advanced. In such a case, an antenna for transmitting and receiving radio waves is required for each of a personal computer, a peripheral device, a mobile phone, and the like. For example, when an antenna is mounted on a personal computer, the rod antenna 32 is mounted so as to be pulled out from the personal computer 31 as shown in FIG. 5 showing various examples of the antenna mounting structure (actually, any one may be provided). , Use it longer,
Antenna 3 in slot provided on the side wall of personal computer
3 can be used.

On the other hand, recently, Bluetooth, wireless LAN,
In mobile phones, etc., antennas are required to be smaller and built-in. When mounting antennas on electronic devices such as personal computers, it is required to be smaller and built-in so that they do not protrude outside. I have.

[0004]

As described above, with the recent miniaturization of electronic equipment, the antenna mounted on the electronic equipment has also been required to be very small, but the antenna emits radio waves in the air. Or receive radio waves in the air. If the size is too small, the efficiency of transmission / reception decreases and the sensitivity deteriorates. For this reason, an antenna that extends from the housing of an electronic device can maintain its performance even if it is slightly reduced in size. Signals must be sent and received.

On the other hand, in recent years, electronic devices such as personal computers have been made of resin for their housings in order to make them lighter and cheaper.
Moreover, in order to prevent unnecessary radiation generated inside and to avoid the influence of noise due to external radio waves, a conductive paint is applied to the inner surface thereof. Therefore, if an antenna is built into the housing of an electronic device such as a personal computer, even if the radio wave radiating surface of the antenna does not reflect or absorb radio waves, a small antenna will also transmit radio waves on the back side. There is a problem that the radio wave that wraps around and leaks into the housing is absorbed in the housing and the antenna efficiency is reduced.

The present invention has been made in order to solve such a problem. Even when an antenna is built in the housing of an electronic device such as a personal computer, radio waves are generated by the housing and parts inside the housing. It is an object of the present invention to provide an antenna mounting structure for preventing the efficiency of the antenna from being reduced by absorbing the antenna.

[0007]

SUMMARY OF THE INVENTION The present inventors have found that when an antenna is built in the housing of an electronic device such as a notebook personal computer, the sensitivity is not reduced as much as possible, and signals are sufficiently transmitted / received even with a small antenna. To be able to
As a result of diligent studies, the ground conductor of the antenna was enlarged by attaching the ground conductor of the antenna to a metal plate such as a shield plate or a frame existing in the housing of the electronic device, or by attaching it so as to make direct contact. It looks like that, and the radio wave wrapping around the back side of the antenna is reduced, the loss inside the housing can be reduced, the radio wave is efficiently radiated out of the housing or received from the outside, and it transmits and receives with high sensitivity I found that I can do it.

That is, as described above, with the recent trend toward smaller and lighter electronic devices, the housing is made of resin, and the inner surface thereof tends to be coated with a conductive paint. The antenna has a large resistance loss for high-frequency signals such as those used for Bluetooth, acts as an absorber, and even if the antenna is mounted so that the front (radiation surface) of the antenna is directly exposed from the housing, It has been found that radio waves circulating on the back side of are attenuated by being absorbed by the conductive paint provided on the inner surface of the housing. If the ground conductor of the antenna is directly contacted and attached to the coating on the inner wall surface of the housing, the resistance loss will be large and will be absorbed, which may lead to a reduction in antenna efficiency. I found it.

According to the antenna mounting structure of the present invention, in the case where the antenna is built in the housing of the electronic device, the radiation surface of the antenna faces outward from the inside of the housing and is mounted on the housing in front of the radiation surface. The material that reflects or absorbs radio waves is prevented from being present, and the ground conductor of the antenna or the ground conductor of the mounting board on which the antenna is mounted is
It is mounted so as to directly contact a metal plate existing in the housing.

[0010] With this configuration, since the ground conductor of the antenna and the metal plate are in direct contact with each other on the surface, the ground conductor functions in the same manner as the size of the metal plate, and the back side of the antenna is (Behind the radiation surface) the transmission of radio waves is blocked. That is, when viewed from the radiating element of the antenna, the ground conductor appears to be large, and the size of the metal plate is many wavelengths long of the signal normally used for transmission and reception, and is 1 /
Since the wavelength is sufficiently larger than two wavelengths, the amount of radio waves radiated from the radiating element radiating to the back side, that is, to the inside of the housing is greatly reduced, and the amount of loss due to being absorbed in the housing is greatly reduced. As a result, it is possible to efficiently transmit and receive signals to and from the outside of the housing with a small antenna while being mounted inside the housing.

The antenna comprises a dielectric antenna in which a radiating element is formed on a front surface side of a dielectric substrate and a ground conductor is provided on a back surface of the dielectric substrate, wherein the ground conductor of the dielectric antenna or the dielectric Since the ground conductor of the mounting board on which the antenna is mounted is brought into direct contact with the metal plate by surface contact, the metal plate completely acts as a ground conductor, and since the metal plate is large, the radiation surface Signal waves are efficiently radiated to the side.

[0012]

Next, an antenna mounting structure according to the present invention will be described with reference to the drawings. The antenna mounting structure according to the present invention is, as shown in FIG. 1, an explanatory view of a state in which an antenna is built in a notebook personal computer as an embodiment, as shown in FIG. The radiation surface 21 (see FIG. 2) of the
1, the housing 11 facing outward from the inside and in front of the radiation surface 21
The grounding conductor 27 of the antenna 2 or the grounding conductor of the mounting board on which the antenna 2 (not shown) is mounted is connected to the shield plate 13 in the housing 11. It is characterized in that it is mounted so as to directly contact a metal plate such as a metal frame 14 (see FIG. 4). What is direct contact?
This means that the ground conductor of the antenna or the ground conductor of the mounting board on which the antenna is mounted is connected to the metal plate by surface contact, instead of being connected via a lead or the like.

FIG. 1 is an explanatory view of a state in which the display unit 1b of the notebook computer 1 is set up, and the main unit 1a is shown.
Is provided with a keyboard (not shown) on the front surface side, and the front side, the periphery, the side surface, and the back surface side are covered with a resin housing 11. FIG. 1 shows a state in which the keyboard and its internal parts have been removed. A metal plate (not shown) for obtaining mechanical strength is provided below the keyboard, and a hard disk or the like is further provided below the metal plate. It has a structure in which a microprocessor or the like is built in, and a shield plate 13 made of metal is provided on the back side thereof so as not to be affected by external noise.

In the example shown in FIG.
An antenna 2 is attached to the ground conductor 3 so that its ground conductor is in direct surface contact with the metal plate, and its radiating surface 21 is mounted so as to face outward from the housing 11. By providing the hollow portion 11a, there is no material that reflects or absorbs on the front surface thereof. However, even if such a hollow portion 11a is not provided, if the above-described conductive paint or other absorbing member, or a metal plate is inside the housing 11, only the portion facing the radiation surface is used. May be removed, and the resin housing may be used. Even when the casing 11 is provided with the hollow portion 11a, it is preferable that the surface thereof be covered with a resin or the like that transmits radio waves.

As shown in FIG. 2, a radiating element 23 is provided on the surface (radiating surface 21) of a dielectric substrate 26 made of ceramics, and a ground conductor 27 is provided on the back surface. The excitation electrode 2 is provided via a power supply electrode 25 from a power supply unit provided on the back side.
A dielectric antenna having a structure in which the radiating element 23 is excited by 2 is used. The ground conductor 27 on the back surface of the antenna 2 is attached to a metal plate such as the above-mentioned shield plate 13 with screws or the like, so that the ground conductor 27 of the antenna 2 is integrated with a large metal plate, and a very large ground conductor is formed. It behaves like an antenna with. In addition, when the antenna 2 and the shield plate 13 were in contact with each other, better electrical contact was obtained when the antenna 2 and the shield plate 13 were securely tightened with screws than using a conductive adhesive. Although the example shown in FIG. 1 is a dielectric antenna, the antenna used is not limited to such a dielectric antenna, and a shortened monopole antenna that radiates signals in all directions can be used.

In this example, a ceramic having a relative dielectric constant of about 8 is used as the dielectric substrate 26. For example, the length (L) × width (M) × height (H) is 15 mm × 7 mm.
× 6mm, 15mm × 4mm × 4mm, 15mm × 3m
It is formed in a size such as mx 2 mm. The larger the volume, the better the antenna performance, but the size of the antenna is determined by the required performance, the space in the electronic device housing, and the like. Further, a material having a dielectric constant as large as possible, for example, BaO—TiO ₂ —SnO ₂ , MgO—CaO—
The performance is further improved by using ceramics such as TiO _{2 having} a relative dielectric constant of about 30 or more,
While the size is about mx 4 mm x 3 mm, the number of radiating elements 23 can be reduced to three, for example, to widen the band.

The ground conductor 27, the excitation electrode 22 and the radiating element 23 can be easily formed by providing a conductive film such as a silver film provided on the dielectric substrate 26 by printing or vacuum deposition and patterning. However, the present invention is not limited thereto, and a structure in which conductive wires or conductive plates of copper or the like are arranged on the dielectric substrate 26 may be used. The length of the radiating element 23 is formed so as to have an electrical length of １ ／ wavelength of the used frequency band in relation to the dielectric constant of the substrate 26. Further, the wider the width, the more the sensitivity contributes to the improvement of the sensitivity. However, the width may be narrower than that shown in the figure, or may be formed on the entire surface of the dielectric substrate 26. The antenna characteristics are improved as the width of the radiating element 23 is increased. Further, the radiating element 23 may be composed of a plurality of antennas, and may be used in a plurality of frequency bands. Alternatively, the resonance frequency of the plurality of antennas may be slightly different to form a wideband antenna.

The excitation electrode 22 causes the radiating element 23 to excite a signal from a feeder (not shown)
The electrode for transmitting the signal received by the to the power supply unit,
It is formed to a length considerably smaller than a quarter wavelength,
The tip of the maximum voltage point is capacitively coupled to the radiating element 23, and the other end is connected to a feeding unit (not shown). In the example shown in FIG. 2, the other end is connected to a power supply unit (not shown) provided on the back surface of the dielectric substrate 26 via the power supply electrode 25. Usually, this antenna
The power supply line is mounted on a mounting substrate having a ground plate, a power supply line, and the like formed on the surface, and the power supply line is connected to a signal processing circuit by a cable. In addition, the ground conductor on the back surface of the mounting board contacts and is connected to the metal plate 13 such as the above-mentioned shield plate.

The example shown in FIG. 1 is an example in which a ground conductor on the back surface of a dielectric antenna is attached to a metal plate such as a shield plate so as to make direct surface contact. However, as shown in FIG. Can be mounted so that the radiation surface 21 faces the outside from the side wall of the personal computer housing 11, that is, the antenna 2 is oriented sideways. However, in this case,
As shown in an enlarged view of the antenna 2 in FIG.
A mounting board 28 on which the antenna 2 is mounted is made of an L-shaped metal plate or the like.
When the antenna is mounted so as to make surface contact with the metal plate 13, the antenna operates as if the entire metal plate 13 was used as the ground conductor of the antenna 2, which is preferable. In FIG. 3, reference numeral 12 denotes a keyboard, and the same parts as those in FIG.

Further, in the above-described example, the metal plate on which the antenna 2 is mounted is an example of the shield plate. However, as described above, the metal plate on the lower side of the keyboard except for each key portion for mechanical reinforcement is also provided. Is provided, and such a metal plate may be used. In addition, as shown in FIG.
There is usually a metal frame 14 on the back side of the device, which may be attached to such a frame 14 as shown in FIG. The metal plate on which the antenna is mounted may be any metal plate as long as it is a metal plate existing in the housing of the electronic device and the antenna 2 can be mounted so that the radiation surface faces the outside of the housing. . Note that the size of the metal plate is 1/1 in the direction of the electric field of the antenna 2 (in the case of the dielectric antenna having the above-described shape, the length direction of the radiating element).
If it is for two wavelengths or more, that is, for 2.4 GHz band Bluetooth, it is sufficient that the length is about 60 mm or more, and a metal plate in an ordinary electronic device, the radiation plate of the antenna can be attached outward. If it is, it can be used almost as it is.

In the above example, the electronic device is a notebook personal computer. However, the electronic device is not limited to the notebook personal computer, but may be a desktop personal computer, a PDA, a portable terminal, a portable telephone,
The present invention can be applied to all electronic devices capable of performing communication with a personal computer, such as digital cameras and home electric appliances, each having a metal plate in a housing.

According to the mounting structure of the present invention, even when a conventional electronic device such as a personal computer is provided with a built-in antenna, the ground conductor of the antenna is not a point but a line or a wire on a metal plate in the housing of the conventional electronic device. Attach the antenna so that it comes into contact with the surface, and make sure that there is no material that absorbs or reflects radio waves in the housing on the radiation side of the antenna. It can be made to act, and it becomes very small that it goes around the back side of the antenna. Even with a small antenna, the transmission and reception sensitivity can be greatly improved. As a result, the design of the conventional electronic device can be incorporated in the electronic device without much change, and it is possible to cope with short-range communication using Bluetooth without any hindrance and with high sensitivity.

[0023]

As described above, note PCs and PDAs
A small antenna can be easily attached to a conventional electronic device such as a printer while maintaining high performance, so that it can be installed between a personal computer and peripheral devices such as a printing press, digital camera, mobile phone, home appliance, etc. Signals can be easily transmitted and received wirelessly between each other, and furthermore, the elimination of wiring greatly contributes to simplification of OA equipment and further simplification of data transfer, which can further promote the development of IT.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of an embodiment of a mounting structure according to the present invention.

FIG. 2 is an explanatory diagram illustrating an example of the antenna of FIG. 1;

FIG. 3 is a diagram illustrating another embodiment of the antenna mounting structure according to the present invention.

FIG. 4 is a diagram illustrating still another embodiment of the antenna mounting structure according to the present invention.

FIG. 5 is an explanatory diagram of a structure for attaching an antenna to a conventional personal computer or the like.

[Description of Signs] 1 Personal computer 2 Antenna 11 Housing 13 Metal plate 14 Frame

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J045 AA21 AB05 AB06 DA09 EA07 MA04 NA01 5J046 AA04 AB13 PA07 5J047 AA04 AB13 EF04

Claims (2)

[Claims] 1. A mounting structure for an antenna built in a housing of an electronic device, wherein a radiation surface of the antenna faces outward from inside the housing and a radio wave is transmitted to the housing in front of the radiation surface. A grounding conductor of the antenna or a grounding conductor of a mounting board on which the antenna is mounted is attached so as to be in direct contact with a metal plate existing in the housing while preventing the presence of a material that reflects or absorbs. Antenna mounting structure. 2. The antenna according to claim 1, wherein the radiating element is formed on a front surface side of a dielectric substrate, and a ground conductor is provided on a back surface of the dielectric substrate. 2. The antenna mounting structure according to claim 1, wherein a ground conductor of the mounting board on which the dielectric antenna is mounted is mounted in contact with the metal plate by direct surface contact.