JP4651411B2 - ANTENNA DEVICE AND RADIO DEVICE - Google Patents

Description

  The present invention relates to a wireless device and an antenna device used for the wireless device, and more particularly to heat dissipation of the device.

  Although portable wireless devices such as mobile phones have been pursued for miniaturization and high performance, heat generation from built-in electronic circuits, electric circuits that drive vibrators, etc. has become a problem. . If the heat generation is not sufficiently dissipated, the temperature inside the wireless device becomes high. The electronic circuit may malfunction due to this high temperature, and even if it does not cause malfunction, in the case of a portable wireless device, in many cases, the user uses it in direct contact with the hand or human head For this reason, there are cases where the user misidentifies that an abnormality has occurred in the wireless device or that the user feels uncomfortable.

  Generally, in the UL standard (information processing equipment-UL1950), the surface temperature of the equipment is determined. According to this, “the outer surface of the device that can be contacted” is a temperature rise of 45 ° C. or less in the case of metal, and 70 ° C. or less in the case of plastic or rubber. When the ambient temperature is 25 ° C., the outer surface of the housing is 70 ° C. for metal and 95 ° C. for plastic or rubber.

  Since many people feel that the actual temperature due to the standard is high, many mobile phones and the like are designed with a margin larger than the temperature defined by the standard.

Also, in the portable telephone or the like, the structure and the conductive parts of the housing portion, the structure for performing the heat radiation by natural convection of the layout or the like of the IC issuing heat is generally applied.

  However, mobile phones are required to be smaller and have higher performance, which tends to increase the amount of heat dissipated inside, and part of the outer surface of the housing to obtain high mechanical strength and metallic texture. In view of the mechanism that heat is easily transmitted to the user by using metal, a more efficient heat dissipation mechanism is required.

  On the other hand, in a portable wireless device typified by a mobile phone, an antenna is required to be built in the housing because of the demand for convenience and design. For example, a linear antenna or a plate antenna is known as an antenna that can be built in the housing, and in general, a plate antenna is often used in view of transmission and reception characteristics.

  As a plate-like antenna, for example, an inverted F antenna having a short-circuit portion in the vicinity of the feeding point position is known. In addition, a loop antenna having a loop shape in a planar shape is also known.

  In the plate antenna, a radiating element is arranged in parallel with the circuit board, and the radiating element is provided with a feeding point for supplying a high-frequency signal and a short-circuit point for impedance matching.

  FIG. 9 is a diagram for explaining an outline of an antenna device provided in a conventional wireless device. In FIG. 9, only a portion related to the antenna device of the wireless device is shown in a simplified manner. In FIG. 9, the wireless device 101 is provided with an electromagnetic shield box 103 on a circuit board 102. The electromagnetic shield box 103 covers a circuit formed on the circuit board 102, thereby preventing electromagnetic noise entering the circuit from the outside and preventing leakage of electromagnetic noise generated in the circuit to the outside.

Antenna equipment has a radiating element 111 which is disposed parallel to the circuit board 102, between the radiating element 111 and the circuit board 102 are connected at the feed section 112 and the short-circuit unit 114. Here, a plate-like antenna having a short-circuit portion such as an inverted F-type antenna is shown as an antenna device. The power feeding unit 112 and the short circuit unit 114 are connected to the circuit board 102 at a power feeding point 113 and a short circuit point 115, respectively. The position of the feeding point 113 is generally the end of the circuit board 102 in order to ensure the antenna characteristic of λ / 4.

  In the antenna device, a certain distance H is required between the circuit board 102 and the radiation element 111 from the viewpoint of antenna characteristics. If this distance H is reduced, the radiation resistance becomes low, which causes deterioration of antenna efficiency and narrowing of the band, so that a certain distance is required. The distance H between the circuit board and the radiating element is one factor that determines the thickness of the wireless device 101. However, since the distance H cannot be made smaller than a certain degree as described above, the antenna device and the wireless device are downsized. Difficult to do.

  Moreover, in order to reduce the loss of the transmission line of the high frequency signal, the high frequency circuit (RF circuit) is generally mounted in the vicinity of the radiating element. In this high-frequency circuit, a transmission power amplifier (power amplifier) that generates a large amount of heat is installed, and circuit components sensitive to temperature characteristics such as a VCO (voltage controlled oscillator) are also mounted.

  Therefore, when designing the layout of circuit components, it is important to take measures against heat in addition to downsizing. Since downsizing and obtaining good cooling performance are contradictory elements, in some cases, either or both of downsizing and thermal countermeasures may be limited.

In general, for example, Non-Patent Document 1 discloses a known technique for thermal design in an electronic circuit. Further, as a heat dissipation mechanism in a wireless device, one that radiates heat generated by a power amplifier by a built-in antenna is known (see Patent Document 1).
JP 2003-218729 A "A complete introduction to thermal design for electronics" Naoki Kunimine Nikkan Kogyo Shimbun July 18, 1997

  In the configuration disclosed in the above patent document, the antenna mass is fixed between the power amplifier mass and the circuit board so that the antenna mass and the power amplifier mass can be fixed at the circuit board portion. It is necessary to design the shape of the antenna and the power amplifier. As described above, a wireless device that needs to be carried, such as a mobile phone, is required to be small, and since there is a limited space in which each component is placed in the housing, the above-described antenna and power amplifier masses are limited. There is a problem that it is not always possible to provide, and in some cases, a necessary mass may not be provided.

  In addition, even if both the masses can be provided, when designed in accordance with the space allowed in the housing, the shape is expected to be complex, and the process of connecting both mass parts However, there is a possibility that a problem that complexity is expected and a long time is required may occur.

  In view of the above, an object of the present invention is to solve the above-described problems and obtain good heat dissipation characteristics in an antenna device and a wireless device.

  The antenna device and the wireless device of the present invention have a configuration in which a short-circuit portion is grounded to a heat-generating component installed on a circuit board in a configuration having a radiating element having a high-frequency signal feeding unit and a short-circuit unit, or processing of a high-frequency signal By adopting a configuration in which the short-circuit portion is grounded to the electromagnetic shield box including the circuit, heat generated in the heat generating component or the high-frequency signal processing circuit is guided to the radiating element through the short-circuit portion, and the radiating element is used as a heat radiating member. Thus, good heat dissipation characteristics are obtained.

  In the configuration according to the present invention, the heat conducting portion for guiding the heat of the heat source to the radiating element is configured by using the short-circuit portion of the radiating element, and the connection between the heat source and the short-circuit point is installed on the circuit board. By making it an electromagnetic shield box including a heat generating component or a high-frequency signal processing circuit, it is less affected by the shape of the space in the housing, simplifies the configuration, and facilitates connection of the short-circuit portion. To do.

  The heat generating component can be a power amplifier or a CPU, and the radiating element can be a plate antenna or a linear antenna.

  As a configuration to improve the heat dissipation characteristics, for example, the short-circuit portion is grounded at a plurality of locations on the circuit board and / or the electromagnetic shield box, and the configuration includes a plurality of fins that configure the heat sink, and the area of the radiating element is The configuration can be increased. As a configuration for increasing the area of the radiating element, the plate-shaped antenna is configured to include a first radiating element surface parallel to the circuit board and a second radiating element surface perpendicular to the circuit board. Connect electrically and thermally.

  Furthermore, it can be set as the structure provided with a space area | region between a radiation element and a circuit board and / or an electromagnetic shielding box. With this space area, it is possible to secure an arrangement area in which the members of the wireless device are arranged in a housing having a limited space. In the wireless device, at least a part of a resin component that constitutes a cooling fan that cools the heat-generating component can be disposed in the space region.

  According to the antenna device of the present invention, good heat dissipation characteristics can be obtained.

  In addition, even within a limited space of a wireless device, the shorted part of the radiating element is grounded on the circuit board or the electromagnetic shield box, so that it is affected by the shape and arrangement of the space. And a mechanism for heat dissipation can be easily configured.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The antenna device of the present invention can use a linear radiating element in addition to the plate-shaped radiating element. In the following description, the plate-shaped radiating element will be described. In addition to the plate-like inverted F-type antenna, the plate-like radiating element can take various forms such as a configuration in which a loop of the loop antenna is formed in a flat shape to form a pseudo plate-like radiating element. However, the following description will be made mainly using a plate-like inverted F-type antenna.

  FIG. 1 is a diagram for explaining the outline of the first aspect of the antenna device of the present invention. FIG. 1 is a diagram for mainly explaining the configuration of the radiating element, and other configurations are omitted. FIG. 1A is a perspective view of the wireless device 1 and the antenna device 10, and FIG. 1B is a side view seen from the direction A in the drawing.

  In FIG. 1, the wireless device 1 includes an electromagnetic shield box 3 on a circuit board 2. The electromagnetic shield box 3 covers a circuit formed on the circuit board 2 to prevent electromagnetic noise entering the circuit from the outside and prevent leakage of electromagnetic noise generated in the circuit to the outside.

  The antenna device 10 includes a radiating element 11 installed in parallel with the circuit board 2, and the radiating element 11 and the circuit board 2 are connected by a power feeding unit 12 and a short-circuit unit 14. Here, a plate-like antenna having a short-circuit portion such as an inverted F-type antenna is shown as an antenna device.

The power supply unit 12 is connected at a power supply point 13 on the circuit board 2 and supplies a high frequency current from a high frequency circuit (not shown) to the radiation element 11. The position of the feeding point 13 is generally the end of the circuit board 102 in order to ensure the antenna characteristic of λ / 4, but the present invention is not necessarily limited to this.

  The short-circuit portion 14 is connected at a short-circuit point 15 on the electromagnetic shield box 3 and is impedance-matched by being grounded to the circuit board 2 via the electromagnetic shield box 3. Further, the short-circuit portion 14 conducts the heat of the electromagnetic shield box 3 to the radiating element 11. In the electromagnetic shield box 3, the heat generating parts such as the power amplifier and the CPU are mounted so as to be disposed immediately below or near the short-circuit point 15, so that the heat generated by the heat generating parts such as the power amplifier and the CPU is short-circuited. The efficiency of heat transfer to 12 can be improved.

  In FIG. 1, the short-circuit point 15 is on the electromagnetic shield box 3, but when a heat-generating component such as a power amplifier (power amplifier) is not covered with the electromagnetic shield box 3, it may be connected to the power amplifier. In this way, the heat generated in the power amplifier may be conducted to the radiating element 11 via the short-circuit portion 14 and radiated in the radiating element 11. When the short-circuit portion 14 is connected to a heat-generating component such as a power amplifier, silicon having good thermal conductivity may be filled around the short-circuit point 15.

  By connecting the radiating element 11 of the antenna device 10 to the electromagnetic shield box 3 via the short-circuit portion 14 and the short-circuit point 15, the heat generated in the heat-generating components such as the power amplifier and CPU provided in the electromagnetic shield box 3 is generated. Heat can be transferred to the radiating element 11 and heat can be radiated from the radiating element 11 to the outside.

  In the wireless device 1, the casing surface covering the antenna device 10 is normally covered with a resin or the like without any metal parts being arranged in order to ensure antenna characteristics. Therefore, even if the user touches the casing portion where the radiating element 11 is arranged, the heat radiated from the radiating element 11 of the antenna device 10 is transmitted to the user through the resin portion. Become. Since the resin has a lower thermal conductivity than the metal, the user does not feel discomfort due to the high temperature unlike when the resin is in contact with the metal part.

  Also, from the viewpoint of ensuring antenna characteristics, the built-in antennas that are usually placed in the housing are laid out in locations where the user's handle is difficult to touch, or the housing structure is designed so that the handle is difficult to touch. Therefore, it can be said that the possibility of touching the heat generation part is smaller than in other places.

  That is, the configuration in which the radiating element of the antenna device is used as a part of the heat dissipation mechanism is an effective configuration from the viewpoint of the actual usage environment of the wireless device such as the antenna characteristics and the structure of the housing, and affects the antenna characteristics. It is possible to take heat countermeasures with a simple configuration without any problems.

  Next, a second aspect of the present invention will be described with reference to FIG. A 2nd aspect improves thermal conductivity by making a short circuit point into multiple places. In the following description, only parts different from the first aspect described above will be described, and description of common parts will be omitted.

  In the perspective view shown in FIG. 2 (a), the antenna device 10 has two short-circuit portions 14a and 14b, and is short-circuited at two short-circuit points 15a and 15b on the electromagnetic shield box 3, and on the electromagnetic shield box 3 side. Heat is conducted to the radiating element 11.

  2 (b) is a side view seen from the direction of arrow A in FIG. 2 (a), and FIG. 2 (c) is a side view seen from the direction of arrow B in FIG. 2 (b). is there.

  In addition to the configuration in which the short-circuit points 15a and 15b are provided close to each other on the electromagnetic shield box 3, the short-circuit points 15a and 15b may be provided according to the arrangement of the heat generating components in the electromagnetic shield box 3, The thermal conductivity can be improved by providing the position.

  In FIG. 2, the two short-circuit points are grounded. However, the number of short-circuit points is not limited to two, and may be three or more, and a configuration in which a plurality of short-circuit points are provided for one short-circuit portion may be employed. . Moreover, you may set the width | variety of the member of a short circuit part as wide, for example, 3 mm.

  Next, a third aspect of the present invention will be described with reference to FIGS. In the third aspect, heat conductivity is improved by providing a heat sink in the radiating element. In the following description, only parts different from the first aspect described above will be described, and description of common parts will be omitted.

  In the perspective view shown in FIGS. 3A and 4A and the side view shown in FIGS. 3B and 4B, the antenna device 10 is provided with a heat sink 16 and a heat sink 17 on the radiating element 11. . The heat sink 16 is composed of a plurality of plate-shaped heat radiation fins, and the heat sink 17 is composed of a plurality of stick-shaped heat radiation pins.

  These heat sinks 16, 17 can be arranged in a space portion (space region 20) formed by a gap between the circuit board 2 and the radiating element 11. Since this space is a portion that is not normally used from the viewpoint of antenna characteristics, it is possible to effectively use this space portion as a space region 20 in which members of the wireless device are arranged.

  Further, a part of the heat sinks 16 and 17 may be brought into contact with the electromagnetic shield box 3 to form a short circuit point. In addition to good heat dissipation by the radiating element 11, heat of the electromagnetic shield box 3 is applied to the radiating element 11. It can also be used as a component to be conducted.

  FIGS. 3B and 4B are side views seen from the direction of arrow A in FIGS. 3A and 4A, respectively.

  Next, the 4th aspect of this invention is demonstrated using FIG. In the fourth aspect, the heat radiation property is improved by extending the radiation element to expand the heat radiation area. In the following description, only parts different from the first aspect described above will be described, and description of common parts will be omitted.

  In the perspective view shown in FIG. 5A, the antenna device 10 includes an extended portion 11 a in addition to the radiating element 11. FIG. 5B is a side view seen from the direction of arrow A in FIG.

  In FIG. 5, the radiating element 11 is installed in parallel to the circuit board 2, while the extension portion 11 a is installed perpendicular to the circuit board 2. The radiating element 11 and the extended portion 11a are formed by bending an integral plate, and the radiating element 11 and the extended portion 11a are prepared as separate members, and at least electrically connect these members. Can be configured. 5 shows an example in which the extended portion 11a is formed on the short side of the circuit board 2, the configuration in which the extended portion 11a is formed on the long side of the circuit board 2, and the short side. It is good also as a structure formed in the both sides of a side and a long side.

  By providing the radiating element 11 with the extended portion 11a, the heat radiation area can be expanded and the heat radiation efficiency can be improved.

  Next, a fifth aspect of the present invention will be described with reference to FIGS. In the fifth aspect, a heat-generating component is provided at a position below the radiating element, and the heat radiation performance is improved by short-circuiting the radiating element with the heat-generating component or with the electromagnetic shield box covering the heat-generating component. It is something to be made. In the following description, only parts different from the first aspect described above will be described, and description of common parts will be omitted. FIGS. 6B and 7B are side views seen from the direction of arrow A in FIGS. 6A and 7A, respectively.

  FIG. 6 shows a configuration example in which the electromagnetic shield box is extended. In FIG. 6, a part of the electromagnetic shield box 3 is extended to a lower part of the radiating element 11, and a short-circuit point 15 is provided on the extension 3a. The short circuit part 14 connects between the radiation element 11 and the short circuit point 15 on the extension part 3a, and conducts heat from the electromagnetic shield box 3 to the radiation element 11.

  Normally, metal parts are not provided below the radiating element 11 from the viewpoint of antenna characteristics. However, the extension of the electromagnetic shield box 3 is limited to a part below the radiating element 11 to deteriorate the antenna characteristics. Can be suppressed.

  FIG. 7 shows a configuration example in which a heat generating component is provided on a circuit board below the radiating element. In FIG. 7, a power amplifier 4 is provided on the circuit board 2 below the radiating element 11, and a short-circuit point 15 is provided on the power amplifier 4. The short-circuit unit 14 connects between the radiating element 11 and the short-circuit point 15 on the power amplifier 4, and conducts heat from the power amplifier 4 to the radiating element 11.

  Normally, metal parts are not provided below the radiating element 11 from the viewpoint of antenna characteristics. However, the area occupied by the power amplifier 4 is reduced as compared with the area of the radiating element 11, thereby deteriorating the antenna characteristics. Can be suppressed. The power amplifier 4 is known to be composed of, for example, a 4 mm square element, and can be sufficiently smaller than the area of the radiating element 11.

  Next, a sixth aspect of the present invention will be described with reference to FIG. In the sixth aspect, a cooling mechanism is provided in a space portion between the radiating element and the circuit board, and heat dissipation is improved by the cooling mechanism. In the following description, only parts different from the first aspect described above will be described, and description of common parts will be omitted. In addition, FIG.8 (b) is the side view seen from the direction of arrow A in Fig.8 (a).

  FIG. 8 shows a configuration example in which a cooling fan 18 is provided as a cooling mechanism. In FIG. 8, the structural member of the cooling fan 18 is provided in the space formed in the gap between the radiating element 11 and the circuit board 2. As described above, a metal part is usually not provided at a position below the radiating element 11 from the viewpoint of antenna characteristics, but any member that does not affect the antenna characteristics, such as resin, can be disposed. Therefore, a resin fan 18 is installed in the space portion among the cooling fans, and the fan 18 is driven to perform forced cooling.

  The constituent member having a metal portion such as a motor for driving the fan 18 can be provided in a portion that does not affect the antenna characteristics such as the back surface of the circuit board 2.

  In the sixth aspect, the cooling mechanism is provided in the space formed between the radiating element 11 and the circuit board 2. However, as shown in the second aspect, the wireless device has other configurations. Members may be placed.

  The antenna device of the present invention can be applied not only to a mobile phone but also to a portable wireless device.

It is a figure for demonstrating the outline of the 1st aspect of the antenna apparatus of this invention. It is a figure for demonstrating the outline of the 2nd aspect of the antenna apparatus of this invention. It is a figure for demonstrating the outline of the 3rd aspect of the antenna apparatus of this invention. It is a figure for demonstrating the outline of the 3rd aspect of the antenna apparatus of this invention. It is a figure for demonstrating the outline of the 4th aspect of the antenna apparatus of this invention. It is a figure for demonstrating the outline of the 5th aspect of the antenna apparatus of this invention. It is a figure for demonstrating the outline of the 5th aspect of the antenna apparatus of this invention. It is a figure for demonstrating the outline of the 6th aspect of the antenna apparatus of this invention. It is a figure for demonstrating the outline of the antenna device with which the conventional radio | wireless apparatus is provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Radio | wireless apparatus, 2 ... Circuit board, 3 ... Electromagnetic shielding box, 3a ... Extension part, 4 ... Power amplifier, 10 ... Antenna apparatus, 11 ... Radiation element, 11a ... Expansion part, 12 ... Feeding part, 13 ... Feeding point , 14, 14a, 14b ... short circuit part, 15, 15a, 15b ... short circuit point, 16, 17 ... heat sink, 18 ... fin, 20 ... space region.

Claims (14)

A circuit board on which heat generating component is installed, the antenna device of the radio apparatus having an electromagnetic shielding box which covers the heat-generating component in the circuit board,
It has a plate-shaped radiating element with a high-frequency signal feeding part and a short-circuit part,
On one end side of the electromagnetic shield box, a space region where the electromagnetic shield box does not exist is formed between the plate-like radiation element and the circuit board, and the power feeding unit feeds power on the circuit board in the space region. It is connected to the point, and wherein the short-circuit portion is grounded on the electromagnetic shielding box, antenna device.   The antenna device according to claim 1, wherein the heat generating component is a power amplifier and / or a CPU.   The antenna device according to claim 1, wherein the radiating element is a radiating element of a plate-like inverted F-type antenna.   The antenna device according to claim 1, wherein the radiating element includes a plurality of fins constituting a heat sink.   The antenna device according to claim 1, wherein the short-circuit portion is grounded at a plurality of locations of the electromagnetic shield box.   The plate-shaped radiating element includes a first radiating element surface parallel to the circuit board, and a second radiating element surface perpendicular to the circuit board, and the first radiating element surface and the second radiating element. The antenna device according to claim 1, wherein the surfaces are connected electrically and thermally. A plate-shaped radiating element provided with a high-frequency signal feeding portion and a short-circuit portion ;
A circuit board on which heat generating components are installed;
And an electromagnetic shielding box which covers the heat generating component in the circuit board,
On one end side of the electromagnetic shield box, a space region where the electromagnetic shield box does not exist is formed between the plate-like radiation element and the circuit board, and the power feeding unit feeds power on the circuit board in the space region. It is connected to the point, and wherein the short-circuit portion is grounded on the electromagnetic shielding box, wireless device. The wireless device according to claim 7 , wherein the heat generating component is a power amplifier and / or a CPU provided in the wireless device. The radio apparatus according to claim 7 , wherein the radiating element is a radiating element of a plate-like inverted F-type antenna. The wireless device according to claim 9 , wherein the radiating element includes a plurality of fins constituting a heat sink. The radio apparatus according to claim 7 , wherein the short-circuit portion is grounded at a plurality of locations on the electromagnetic shield box. The plate-like radiation element includes a first radiation element surface parallel to the circuit board and a second radiation element surface perpendicular to the circuit board, and the first radiation element surface and the second radiation element. The radio apparatus according to claim 7 , wherein the surfaces are at least electrically connected, and the first and second radiating element surfaces are insulated from an inner wall of the housing. The plate-like radiation element includes a first radiation element surface parallel to the circuit board and a second radiation element surface perpendicular to the circuit board, and the first radiation element surface and the second radiation element. 8. A wireless device according to claim 7 , characterized in that the surfaces are connected electrically and thermally. A cooling fan composed of resin parts that cools the heat-generating parts provided in the wireless device,
The radio apparatus according to claim 7 , wherein at least a part of the cooling fan is disposed in the space area.

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