JPH07263941A - Moving body communication machine - Google Patents

Abstract

PURPOSE:To constitute a non-directional device to stabilize the reception level and to miniaturize the device by arranging plural antennas so that their directional patterns are compensated by one another and mounting them on the surface of a circuit board. CONSTITUTION:Two small-sized antennas 8 having dipole type directivities are closely arranged at right angles like inverse T and are mounted as a diversity device on the same surface of a circuit board 13 attached in a portable telephone set main body 21. Consequently, two antennas 8 compensate low-gain parts each other, and the resultant directional pattern is spherical and shows a non-directional pattern. Thus, the reception level is fixed independently of the using direction of a portable telephone set 22 to realize stable reception, and the device is miniaturized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication device having a built-in antenna, and more specifically to the arrangement of the antenna.

[0002]

2. Description of the Related Art As a conventional mobile communication device, for example, in a mobile phone, as shown in FIG. 6, an omnidirectional whip antenna 30 is attached so as to project above an upper part of a mobile phone 31, and at the A plate-shaped inverted F antenna 33 is attached to the circuit board 32, and radio waves are transmitted from the whip antenna 30 during transmission, and the whip antenna 30 and the inverted F antenna 33 constitute a space diversity device during reception.

[0003]

However, in the above-mentioned conventional mobile phone, the whip antenna 30 and the inverted F are used.
Since the antenna 33 has a large shape and its mounting position is restricted, it imposes restrictions on the design and downsizing of the mobile phone 31. Also, the whip antenna 30 and the inverted F antenna 3
Since the space diversity device is composed of 3 and 3, depending on the direction in which the mobile phone 31 is used, it may not match the directivity of the vertically polarized wave that is the received radio wave, resulting in a decrease in reception level and instability. The reception performance was poor.

The present invention has been made to solve such a problem, and an object thereof is to provide a small-sized mobile communication device in which the directional characteristics of the antenna are nondirectional.

[0005]

In order to achieve the above object, according to the present invention, a plurality of surface mount antennas are arranged on the circuit board in a direction in which the directivity characteristics are complemented with each other. It is a feature.

In addition, a dipole type directional characteristic 2
It is characterized in that two surface mount antennas are arranged at right angles to each other and surface mounted on a circuit board.

Further, the plurality of surface mount antennas are
It is characterized by being used in a diversity device.

[0008]

According to the above construction, since the plurality of surface mount antennas are arranged so as to compensate for the weak directions of the radio waves of the respective surface mount antennas, the combined directional characteristics become omnidirectional. Become.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mobile communication device according to the present invention, for example, an embodiment of a mobile phone will be described below with reference to the drawings. Figure 1
FIG. 3 is a perspective view of an antenna used in the mobile phone of the present invention. In FIG. 1, reference numeral 1 denotes a rectangular parallelepiped dielectric substrate made of ceramic or resin, and a linear radiation electrode 2 is formed on the surface of the dielectric substrate 1 in parallel with the long side direction, and one side surface on the short side is formed. A power supply electrode 3 that is electrically connected to the radiation electrode 2 is formed on the above, and a first ground electrode 4 that is electrically connected is formed above the power supply electrode 3. On the other hand, a second ground electrode 5 is formed on almost the entire back surface of the dielectric substrate 1, and fixed electrodes 6 electrically connected to the ground electrode 5 on the back surface are formed on both side surfaces of the dielectric substrate 1 on the long side. And the antenna 8 is formed. The first ground electrode 4 and the second ground electrode 5 are electrically connected under the ground electrode 4.

Then, the antenna 8 is placed on the circuit board 13 having the power supply line 11 and the ground electrode 12, the power supply line 11 and the power supply electrode 3 are connected, and the ground electrode 4, the fixed electrode 6 and the ground electrode 12 are connected. And the antenna 8 is surface-mounted.

The antenna 8 thus constructed has the power supply electrode 3, the ground electrode 4 and the fixed electrode 6 formed on the side surface,
Since the bottom surface of the dielectric substrate 1 is flat, the circuit board 1
3, the directional characteristic of the antenna 8 is a dipole shape of a figure 8 in the short side direction (the direction perpendicular to the radiation electrode 2) of the antenna 8 as shown in FIG. Also,
Since the antenna 8 has the dielectric substrate 1, the radiation electrode 2
If the dielectric constant between the ground electrode 5 and the ground electrode 5 is increased and the resonance frequencies are the same, the antenna shape can be downsized. Therefore, restrictions on the mounting position on the circuit board 13 are reduced.

FIG. 3 is a partial sectional view of a mobile phone according to the first embodiment of the present invention. As shown in FIG. 3, two antennas 8 and 8 are arranged in a reverse T-shape at right angles on the same surface of the circuit board 13 mounted inside the mobile phone body 21 and mounted on the surface. , The mobile phone 22 is configured. The antennas 8 and 8 are used in the diversity device. The right-angled direction is a direction in which the central axis of the antenna 8 in the longitudinal direction (direction parallel to the radiation electrode 2) intersects at right angles between the two antennas.

As shown in FIG. 4, the directional characteristics of the mobile phone 22 constructed in this manner are such that the antennas 8 are arranged on the circuit board 13 at right angles to each other. The low portion is compensated, and the directional characteristic 9 synthesized by the antennas 8 and 8 is spherical and omnidirectional. In FIG. 4, the solid line represents the directional characteristic of the antenna 8 arranged vertically, and the broken line represents the directional characteristic of the antenna 8 arranged horizontally. Therefore, the mobile phone 22
No matter which direction is used, vertically polarized radio waves can be received at the same level.

When the antennas 8 and 8 are arranged close to each other, since the antennas 8 and 8 are small, the central axes are close to each other,
It is possible to obtain omnidirectionality closer to a true spherical shape. Further, when the antennas 8 are spaced from each other, a space diversity effect can be obtained.

FIG. 5 is a partial sectional view of a mobile phone according to the second embodiment of the present invention. As shown in FIG. 5, the two antennas 8 are arranged on the front and back surfaces of the circuit board 13 mounted inside the mobile phone main body 21 at right angles with the circuit board 13 in between, and are surface-mounted on the circuit board 13. The mobile phone 23. Mobile phone 2 configured in this way
The directional characteristic of 3 is also omnidirectional, and omnidirectional closer to a true spherical shape can be obtained than that of the mobile phone 22.

The antennas 8 and 8 can be arranged in a T-shaped or L-shaped right angle direction other than the orthogonal arrangement. In this case, the space diversity effect can be obtained by separating the antennas 8 from each other.

The number of antennas that can be used in the mobile communication device according to the present invention is not limited to two, but three or more can be used, and the arrangement can be radial or circular. That is, in the directional characteristics of the individual antennas, the weak direction of the radio wave may be supplemented by another antenna so that the combined directional characteristics are omnidirectional. Since the transmitting antenna is compatible with vertically polarized waves, it is preferable to use the antenna 8 in which the radiation electrode 2 of the antenna 8 is arranged in the vertical direction with respect to the ground.

[0018]

As described above, according to the mobile communication device of the present invention, since the plurality of antennas are arranged so as to supplement the weak directions of the radio waves of the respective antennas, there is no directional characteristic. It is possible to provide a mobile communication device which becomes directional and does not cause a decrease in reception level or instability in any direction.

Further, since the built-in antenna is small and can be surface-mounted on the circuit board, restrictions on the mounting position thereof are reduced, which can contribute to simplification and size reduction of the mobile communication device. .

[Brief description of drawings]

FIG. 1 is a perspective view of an antenna used in a mobile communication device of the present invention.

FIG. 2 is a directional characteristic diagram of the antenna of FIG.

FIG. 3 shows a mobile communication device according to the first embodiment of the present invention,
(A) is a side sectional view, and (b) is a rear surface sectional view.

FIG. 4 is a directional characteristic diagram of the mobile communication device of FIG.

FIG. 5 shows a mobile communication device according to a second embodiment of the present invention,
(A) is a side sectional view, and (b) is a rear surface sectional view.

FIG. 6 is a partial cross-sectional view of a conventional mobile communication device.

[Explanation of symbols]

 8 antenna 13 circuit board 21 mobile phone body 22, 23 mobile phone

Claims (3)

[Claims] 1. A mobile communication device in which a plurality of surface mount antennas are arranged in a direction in which directivity characteristics are mutually complemented and surface mounted on a circuit board. 2. A mobile communication device in which two surface mount type antennas having dipole type directional characteristics are arranged at right angles to each other and surface mounted on a circuit board. 3. A mobile communication device using the plurality of surface mount antennas according to claim 1 or 2 in a diversity device.