JP2001102834A - Radio communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide radio communication equipment capable of suppressing the noise of high frequency components generated in a control circuit from being inputted through a ground surface to a high frequency circuit without damaging the antenna characteristics of a monopole antenna. SOLUTION: This equipment is provided with a circuit board 15 of a multilayer substrate mounting a high frequency circuit 11 provided with a MO DEM circuit or the like to operated with a high frequency signal and a control circuit part 13 provided with a logic IC or the like to be operated with digital signal, a monopole antenna 17 of λ/4 length connecting one terminal to the high frequency circuit 11 and an auxiliary antenna 19 having nearly the same antenna characteristics as the monopole antenna 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication apparatus such as a portable telephone, and more particularly to a circuit board having a high-frequency circuit section and a control circuit section mounted thereon. The present invention relates to a wireless communication device having an antenna configured to suppress an input to a high-frequency circuit unit.

[0002]

2. Description of the Related Art As a conventional wireless communication apparatus, for example, there is one as shown in FIG. In FIG. 1, a wireless communication device 100 of the related art includes a circuit board 107 of a multi-layer board in which a high-frequency circuit unit 103 and a control circuit unit 105 are mounted in a housing 101, and has a λ / 4 length (1 / 4
Wavelength) monopole antenna 109 is provided.
The monopole antenna 109 is generally used as an antenna suitable for a wireless communication device requiring a small size, and is connected to an antenna plug 111 provided in the high-frequency circuit section 103 of the circuit board 107. That is, with such a configuration, the high-frequency circuit unit 103 performs communication via the monopole antenna 109.

In general, the monopole antenna 109 has unstable antenna characteristics as compared with antennas such as a dipole antenna and a sleeve antenna. To obtain stable antenna characteristics, a wide and stable ground plane is required as an antenna ground. It is said. Therefore, conventionally, one layer of the circuit board 107 is used as a conductor ground plane (not shown) of the entire surface to stabilize the antenna characteristics of the monopole antenna 109.

[0004]

However, in the conventional wireless communication apparatus 100, the high-frequency circuit section 103 and the control circuit section 105 are integrally mounted on the circuit board 107, and the monopole antenna 109 When the ground of the portion of the board ground plane close to the control circuit section 105 plays a role as the antenna ground, the noise of the high frequency component generated in the control circuit section 105 is not transmitted through the space but is transmitted through the board ground plane. There is a problem that the signal is input to the circuit unit 103.

In recent wireless communication devices, it is necessary to reduce the area of the circuit board due to the demand for miniaturization of the device, and the area of the ground plane of the board is also reduced. There is also a problem that sufficiently stable antenna characteristics cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. In a wireless communication apparatus having a circuit board on which a high-frequency circuit section and a control circuit section are mounted, the antenna characteristics of a monopole antenna are reduced. An object of the present invention is to provide a wireless communication device capable of suppressing noise of a high-frequency component generated in a control circuit unit from being input to a high-frequency circuit unit via a substrate ground plane without loss.

[0007]

According to a first aspect of the present invention, there is provided a radio communication apparatus including a high frequency circuit operating at a high frequency and a control circuit controlling the high frequency circuit. And a monopole antenna connected to the high-frequency circuit section, and a grounded auxiliary antenna having substantially the same antenna characteristics as the monopole antenna.

According to a second aspect of the present invention, in the wireless communication apparatus according to the first aspect, the auxiliary antenna is installed in a direction spatially symmetric with the monopole antenna.

According to a third aspect of the present invention, in the wireless communication device according to the first or second aspect, the auxiliary antenna is a chip antenna.

[0010] Furthermore, a wireless communication device according to claim 4 is
The wireless communication device according to claim 1, 2 or 3,
The monopole antenna is an inverted F antenna, an inverted L antenna, or an M-shaped antenna.

In the radio communication device according to the present invention, a grounded auxiliary antenna having substantially the same antenna characteristics as a monopole antenna is provided. As a result, the antenna ground of the monopole antenna, which has been widely dispersed in the past, can be concentrated on the ground point of the auxiliary antenna, and high frequency component noise generated in the control circuit unit of the circuit board is transmitted through the circuit board ( In particular, it is possible to suppress input to the high-frequency circuit section (via a conductive layer for grounding provided on the circuit board). Therefore, it is possible to prevent malfunction of the high-frequency circuit portion caused by noise of the high-frequency component, or to prevent noise from being mixed into a transmission / reception signal processed by the high-frequency circuit portion.

Although a monopole antenna is composed of an antenna element and a ground plane having a wide constant potential, it is difficult to form an ideal ground plane having a wide constant potential. It is difficult to obtain improved antenna characteristics. On the contrary,
In the wireless communication device according to the present invention, since the auxiliary antenna is added to the monopole antenna, stable antenna characteristics substantially equivalent to those of the dipole antenna can be obtained, and higher reception sensitivity can be obtained.

[0013] In the wireless communication apparatus according to the second aspect,
Since the auxiliary antenna is installed in a spatially symmetric direction with respect to the monopole antenna, the device can be configured without affecting basic characteristics of the antenna such as antenna gain and directivity with respect to the monopole antenna. . Therefore, it is not necessary to change the design of the circuit board due to the change in the antenna characteristics.

Further, in the wireless communication apparatus according to the third aspect,
It is desirable that the auxiliary antenna be a chip antenna having a small size. In this case, the size of the device can be reduced.

Further, even if the monopole antenna is an inverted F antenna, an inverted L antenna, or an M-type antenna as in the radio communication apparatus according to the fourth aspect, these have the same antenna characteristics as the monopole antenna. The same operational effects as those of the wireless communication device according to the first, second, and third aspects can be obtained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a wireless communication apparatus according to the present invention will be described in detail in the order of [first embodiment] and [second embodiment] with reference to the drawings.

[First Embodiment] FIG. 1 shows a first embodiment of the present invention.
FIG. 2 is a configuration diagram of a wireless communication device according to an embodiment. In FIG. 1, a wireless communication device 10 of the present embodiment includes a circuit board 15 on which a high-frequency circuit unit 11 and a control circuit unit 13 are mounted.
, A monopole antenna 17, an auxiliary antenna 19,
A housing 21 is provided.

First, as described above, the circuit board 15 includes a high-frequency circuit section 11 including a modulation / demodulation circuit and the like operated by a high-frequency signal, and a control circuit including a logic IC and the like operated by a digital signal. This is a configuration in which the circuit unit 13 is mounted. Further, the circuit board 15 is a multilayer board, and a conductor surface of a ground potential (not shown) (hereinafter, referred to as a board ground plane) is provided on one layer of the circuit board 15. The board ground plane stabilizes the ground potential of the entire circuit, and its effect is greater as the area is larger. However, in this embodiment, the board ground plane is provided on the entire surface of the circuit board 15. No need.

The monopole antenna 17 has a length of λ / 4, and has one end connected to the high-frequency circuit section 11 of the circuit board 15.
Is connected via a spring (not shown). A transmission signal modulated by the high-frequency circuit unit 11 is transmitted from the monopole antenna 17, and a reception signal is received by the monopole antenna 17.

Further, it is sufficient that the auxiliary antenna 19 has substantially the same antenna characteristics as the monopole antenna 17, but in the present embodiment, an antenna having exactly the same antenna characteristics as the monopole antenna 17 is used. I have. The auxiliary antenna 19 is connected to the monopole antenna 17 in a spatially symmetric direction at one point (hereinafter, referred to as a substrate ground point) 25 of the substrate ground plane provided on the circuit board 15.

As described above, according to the wireless communication device 10 of the present embodiment, the auxiliary antenna 19 having the same antenna characteristics as the monopole antenna 17 is connected to the board ground point 25 of the circuit board 15 so as to be widely dispersed. The antenna ground of the monopole antenna 17 which has been
Control circuit 13 when the digital signal rises or falls.
The noise of the high-frequency component generated by the above can be suppressed from being input to the high-frequency circuit section 11 via the substrate ground plane. Therefore, it is possible to prevent malfunction of the high-frequency circuit unit 11 caused by noise of the high-frequency component, or mixing of noise into transmission / reception signals subjected to modulation / demodulation processing in the high-frequency circuit unit 11.

Further, as shown in FIG. 2A, an ideal monopole antenna is constituted by an antenna element and a ground plane 27 having a wide constant potential, and is indicated by a dotted line which does not actually exist on the ground plane 27 side. It is considered that the antenna has a mirror image. Therefore, an ideal monopole antenna can obtain stable antenna characteristics equivalent to those of the dipole antenna shown in FIG. However, a small-sized device such as a mobile phone cannot provide a sufficiently large ground plane, and thus a monopole antenna cannot obtain stable antenna characteristics like a dipole antenna.

However, in the wireless communication apparatus 10 of the present embodiment, as shown in FIG. 2 (c), a configuration in which a λ / 4-length auxiliary antenna 19 grounded to a λ / 4-length monopole antenna 17 is added. So that it is possible to obtain a stable antenna characteristic almost equivalent to a dipole antenna,
Higher receiving sensitivity can be obtained.

Further, by arranging the auxiliary antenna 19 in a direction symmetrical to the monopole antenna 17, it is possible to prevent the monopole antenna 17 from affecting basic antenna characteristics such as antenna gain and directivity. 10 can be configured. Therefore, it is not necessary to change the design of the circuit board due to the change of the basic characteristics of the antenna.

In this embodiment, the auxiliary antenna 19
Although the board ground plane of the circuit board 15 is used for grounding,
It may be connected to another ground such as a conductive housing. Therefore, in the present embodiment, it is not necessary to provide the circuit board 15 with the board ground plane.

[Second Embodiment] FIG. 3 is a block diagram of a wireless communication apparatus according to a second embodiment of the present invention. In the figure, the same parts as those in FIG. 1 (first embodiment) are denoted by the same reference numerals, and description thereof is omitted. As in the first embodiment, the wireless communication device 30 of the present embodiment includes a circuit board 15 on which the high-frequency circuit unit 11 and the control circuit unit 13 are mounted.
, A monopole antenna 17, an auxiliary antenna 19,
And an auxiliary antenna 1.
As 9, a chip antenna 19 b having substantially the same antenna characteristics as the monopole antenna 17 is used.

Therefore, the wireless communication device 2 of the present embodiment
According to No. 0, since the auxiliary antenna 19 is a small-sized chip antenna 19b, the same effect as that of the first embodiment can be obtained while the wireless communication device 10 of the first embodiment is obtained.
The device can be made more compact as compared with.

Next, FIG. 4 is an explanatory diagram illustrating an application form of the wireless communication device 10 according to the first embodiment or the wireless communication device 30 according to the second embodiment. As shown in FIG. 1, a wireless communication device 10 or 30 is connected to a mobile computer 4 such as a notebook computer or a personal digital assistant (PDA).
Even when the monopole antenna 17 is inserted into the predetermined slot, the grounding surface of the board is not used as the antenna ground of the monopole antenna 17, but the structure is concentrated on one point of the board ground point 25. It is possible to suppress the noise of the high-frequency component from being input to the high-frequency circuit unit 11 of the wireless communication device 10 or 30 via the substrate ground plane, and it is possible to construct a mobile system having excellent noise resistance.

In the first or second embodiment, the monopole antenna 17 is used. However, the inverted L antenna having the same principle and the same antenna characteristics as the monopole antenna (see FIG. 5A). , Inverted F antenna (FIG. 5 (b)
The same effects as those of the first or second embodiment can be obtained even if an M-type antenna or the like is used.

[0030]

As described above, according to the radio communication apparatus of the present invention, since a grounded auxiliary antenna having substantially the same antenna characteristics as a monopole antenna is provided, it has conventionally been widely dispersed. The antenna ground of the monopole antenna can be concentrated on the grounding point of the auxiliary antenna, and the noise of the high frequency component generated in the control circuit section of the circuit board passes through the circuit board (particularly, the grounding provided on the circuit board). Input to the high-frequency circuit unit (via a conductive layer for the purpose). Therefore, it is possible to prevent malfunction of the high-frequency circuit portion caused by the noise of the high-frequency component, or to prevent noise from being mixed into a transmission / reception signal processed by the high-frequency circuit portion.

Although a monopole antenna is composed of an antenna element and a ground plane having a wide constant potential, it is difficult to form an ideal ground plane having a wide constant potential. Although it is difficult to obtain the antenna characteristics described above, the wireless communication device of the present invention has a configuration in which the auxiliary antenna is added to the monopole antenna, so that it is possible to obtain the same stable antenna characteristics as the dipole antenna, Higher receiving sensitivity can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a wireless communication device according to a first embodiment of the present invention.

2A is an explanatory diagram showing an antenna configuration of a monopole antenna, FIG. 2B is an explanatory diagram showing an antenna configuration of a dipole antenna, and FIG. 2C is an explanatory diagram showing an antenna configuration of the present invention.

FIG. 3 is a configuration diagram of a wireless communication device according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a state in which the wireless communication device according to the present invention is inserted into a mobile computer.

5A is an explanatory diagram illustrating an inverted L antenna, and FIG. 5B is an explanatory diagram illustrating an inverted F antenna.

FIG. 6 is a configuration diagram showing a conventional wireless communication device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 High frequency circuit part 13 Control circuit part 15 Circuit board 17 Monopole antenna 19 Auxiliary antenna 21 Housing 23 Antenna plug 25 Board ground point

Claims (4)

[Claims] 1. A circuit board on which a high-frequency circuit section operating at a high frequency and a control circuit section for controlling the high-frequency circuit section are mounted; a monopole antenna connected to the high-frequency circuit section; and substantially the same as the monopole antenna. And a grounded auxiliary antenna having the above antenna characteristics. 2. The wireless communication apparatus according to claim 1, wherein the auxiliary antenna is installed in a direction spatially symmetric with the monopole antenna. 3. The wireless communication device according to claim 1, wherein the auxiliary antenna is a chip antenna. 4. The wireless communication device according to claim 1, wherein the monopole antenna is an inverted F antenna, an inverted L antenna, or an M-type antenna.