JPH06314984A - Mobile communication equipment - Google Patents

Abstract

PURPOSE:To prevent the characteristic of an inverted F antenna built in the mobile communication equipment from being deteriorated due to the effect of a human body and to make the equipment small. CONSTITUTION:An inverted-F plate antenna in which a dielectric board 16 whose one side is formed with a metallic foil 15 is provided closely to a metallic member 17 is arranged to an upper part of a case 1 so that the dielectric board 16 is made perpendicular to a 1st side 5 of the case 1 of the mobile body communication equipment having at least a reception section 4. Furthermore, the metallic member 17 is formed to be an L-shape comprising a 1st side 17a on which the dielectric board 16 is closely provided and a 2nd side 17b perpendicular to the 1st side, and the 2nd side is arranged along a rear side 18 of the case.

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 so-called plate-shaped inverted F antenna in which a dielectric substrate having a metal foil formed on one surface is provided in close contact with a metal member. .

[0002]

2. Description of the Related Art In recent years, with the development of mobile communication devices such as mobile phones and car phones, there has been an increasing demand for miniaturization of these devices. As a result, the antennas used in the communication devices have become smaller and smaller. There is a demand for a built-in antenna that has high gain and can be placed inside the housing. An inverted F antenna is an antenna element suitable for such an application.

An inverted F antenna is a linear inverted F antenna, which is formed as a printed pattern on a dielectric substrate inside a communication device due to the shape of the element.
Plate-shaped inverted F that has an antenna and a dielectric independently for the antenna element
Can be roughly divided into antennas. The principle of operation is the same for both. The plate-shaped inverted F antenna is a small antenna with a perimeter of about 1/2 wavelength, and unlike an ordinary dipole antenna, it is an antenna that can transmit and receive in a relatively wide range on any of XY, YZ, and ZX planes. Both polarization components can be received.

Such a plate-shaped inverted F antenna is disclosed in, for example, Japanese Patent Application Laid-Open No. 4-129302 (H01Q 1/2).
As described in 4), a small and thin antenna that can be built in the device body has been proposed. In this prior art,
A dielectric substrate is provided in close contact with a casing made of a metal material, and an antenna element made of a metal foil containing a comb-shaped pattern composed of a plurality of irregularities on at least one side is formed on the dielectric substrate. A part of the edge of the antenna element is grounded to the housing with a metal wire or a metal strip, and power is supplied between a slit formed between the antenna element and the housing near the metal wire or metal strip. Is.

In an actual mobile communication device, such an antenna is arranged in a housing as shown in FIG. 3, for example, and is used for diversity at the time of reception. In the figure, (A) is a partially cutaway side view, and (B) is a front view of the same. Reference numeral 1 is a housing of a communication device main body, 2 is rotatably mounted on the housing 1, and a microphone (not shown) is provided. The built-in transmitter section 3 is an operation button such as a numeric keypad or a function key, and 4 is an earpiece speaker attached to one surface 5 of the housing 1. Reference numeral 6 denotes a plate-shaped inverted F antenna. The plate-shaped inverted F antenna 6 is provided with a dielectric substrate 7 having a metal foil 8 formed on one surface in close contact with a metal plate 9, and the metal foil 8 and the metal plate 8. 9 are electrically connected by a conductive member 10, and power feeding 11 is further performed between the metal foil 8 and the metal plate 9. Reference numeral 12 is a normal transmitting / receiving rod antenna.

[0006]

When an antenna is built in a housing of a mobile communication device, the main body of the device is directly held in the hand and used, so that it is directly affected by the human body.
Antenna characteristics such as the resonance frequency, gain, and directional characteristics of the antenna are significantly deteriorated. In the mobile communication device according to the related art shown in FIG. 3 described above, in order to minimize the influence of the human body, the dielectric substrate 7 on which the metal foil 8 is formed is arranged on the upper part of the housing 1, and the device main body is provided. Even if the hand is held by hand, the antenna portion is not directly covered, but depending on how to hold the antenna portion, the antenna portion may be covered, which causes the antenna characteristics to deteriorate.

Further, in the above-mentioned conventional inverted-F antenna, mounting a ground potential component next to the antenna mounting surface adversely affects the antenna characteristics.
Parts cannot be arranged in the region 13 shown by the dotted line, which has a drawback that the miniaturization of the product is hindered.

[0008]

In order to solve the above-mentioned problems of the prior art, in the mobile communication device of the present invention, a dielectric substrate having a metal foil formed on one surface is provided in close contact with the metal member. In a mobile communication device having a plate-shaped inverted F antenna, the dielectric substrate of the plate-shaped inverted F antenna is perpendicular to the first surface of the casing of the mobile communication device, which has at least the earpiece, and the casing. It is characterized by being placed on the upper part of the body.

Further, in the mobile communication device of the present invention, the first metallic member is provided in close contact with the dielectric substrate.
And a second surface perpendicular to the first surface, which is L-shaped, and the second surface is arranged along the back surface of the housing.

[0010]

The dielectric substrate of the plate-shaped inverted F antenna is arranged vertically to the first surface of the main body housing having the earpiece and at the top of the housing. There is no obscurity.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a mobile communication device according to the present invention. As in the prior art of FIG. 3, (A) is a partially cutaway side view and (B) is a front view. Further, the same configurations as those in FIG. 3 are denoted by the same reference numerals, and the description thereof will be omitted. 14 is a plate-shaped inverted F antenna, and has a metal foil 15 on one surface.
The dielectric substrate 16 on which is formed is adhered and fixed to the metal plate 17. The metal plate 17 has an L-shape including a first surface 17a provided in close contact with the dielectric substrate and a second surface 17b perpendicular to the first surface. And this plate-shaped inverted F
The antenna 14 is arranged such that the dielectric substrate 16 is perpendicular to the first surface 5 on which the receiving speaker 4 is arranged, and the metal plate 1
The second surface 17b of the second main body 7 is arranged in the housing 1 along the rear surface 18 of the main body.

Next, power feeding and diversity reception of the mobile communication device according to the present invention will be described with reference to FIG. The metal foil 15 of the plate-shaped inverted F antenna 14 is a conductive member 19.
Is electrically connected to the first surface 17a of the metal plate 17 and is connected to the detection circuit 22 by the power supply line 20. On the other hand, the rod antenna 12 is electrically connected to the metal plate 17 by the connecting portion 17c, and is also connected to the detection circuit 23 by the power supply line 21. The reception signals are detected by the detection circuits 22 and 23, and a signal (RSSI) indicating the electric field strength is sent to the control circuit 24. The control circuit 24 uses the RSSI signal to transmit the plate-shaped inverted F antenna 14
It is determined which of the reception intensity of the rod antenna 12 and the reception intensity of the rod antenna 12 is large, and the switch 25 is switched to send either one to the demodulation circuit 26.

It should be noted that the connection point of the conductive member 19 and the power supply line 20 to the metal foil 15 should be as far away from the rod antenna 12 as possible to improve the diversity reception performance. In this embodiment, the rod antenna of the dielectric substrate 16 is improved. It is arranged at the end opposite to 12.

Next, the characteristics of the mobile communication device according to the present invention will be described in comparison with the prior art. 4 shows a model for a characteristic measurement experiment of a plate-shaped inverted F antenna used in the mobile communication device. FIG. 1A shows a plate-shaped inverted F antenna used in the mobile communication device according to the present invention, in which the dielectric substrate 28 having the metal foil 27 is formed on the first surface 29a of the L-shaped metal plate 29. It is in close contact with.
Further, FIG. 3B shows a plate-shaped inverted F antenna used in the conventional technique shown in FIG. 3, in which a dielectric substrate 28 on which a metal foil 27 is formed is attached to an L-shaped metal plate 29. It is closely attached to the second surface 29b. Note that the X, Y, and Z coordinates are defined as shown in the figure.

FIG. 5 shows VSWR (standing wave ratio) characteristics of the plate-shaped inverted F antenna shown in FIG. 4, and FIG. 5A shows the VSWR (standing wave ratio) according to the present invention shown in FIG. 4A. FIG. 4B is based on the conventional technique of FIG.

As shown in FIG. 5A, in the plate-shaped inverted F antenna according to the present invention, the frequency bandwidth of VSWR of 1.5 or less is 56 MHz, and the conventional 26 MHz shown in FIG. Almost twice as much. Therefore, when the mobile communication device is used, there is a sufficient margin even if the center frequency is largely shifted due to the influence of the human body.

FIGS. 6 to 8 respectively show XY of the plate-shaped inverted F antenna according to the present invention and the prior art shown in FIG.
4A and 4B show measurement results of radiation pattern characteristics on a plane, a YZ plane, and a ZX plane. In each drawing, FIG. 4A is according to the present invention of FIG. 4A, and FIG. )
Of the prior art.

The above antenna characteristics are summarized in a table as shown in Table 1.

[0019]

[Table 1]

The plate-shaped inverted F antenna according to the present invention is inferior to the prior art in the average gain of the vertically polarized component,
Other characteristics are superior to those of the prior art, and especially in mobile communication devices such as mobile phones, radio waves are vertically polarized, and considering that the communication device is used vertically during a call, according to the present invention. The XY plane peak gain and the average gain of the vertically polarized components are much higher than those of the conventional technology.
It turns out to be excellent.

[0021]

As described above, in the mobile communication device according to the present invention, the dielectric substrate of the plate-shaped inverted F antenna is perpendicular to the first surface of the main body housing having the earpiece and the housing. Since it is placed on the upper part of the antenna, it is possible to prevent the antenna characteristic from being deteriorated due to the influence of the human body without directly covering the antenna portion when it is held in the hand. In addition, the metal member has an L-shape including a first surface provided in close contact with the dielectric substrate and a second surface perpendicular to the first surface, and the second surface extends along the back surface of the housing. Since it is arranged, the antenna part and the circuit part inside the telephone can be completely separated by the metal plate, the space can be effectively utilized, and the product can be miniaturized.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a mobile communication device according to the present invention.

FIG. 2 is a block diagram of a mobile communication device according to the present invention.

FIG. 3 is a partial cross-sectional view of a conventional mobile communication device.

FIG. 4 is a diagram showing a model for a characteristic measurement experiment of a plate-shaped inverted F antenna used in a mobile communication device, (A) showing the present invention, and (B) showing a conventional technique.

5 is a graph showing VSWR (standing wave ratio) characteristics of the plate-shaped inverted F antenna shown in FIG. 4, where (A) represents the present invention;
(B) shows a conventional technique.

6A and 6B are graphs showing radiation pattern characteristics on the XY plane of the plate-like inverted F antenna shown in FIG. 4, in which FIG. 6A shows the present invention and FIG.

7A and 7B are graphs showing a radiation pattern characteristic on the YZ plane of the plate-like inverted F antenna shown in FIG. 4, where FIG. 7A shows the present invention and FIG.

8A and 8B are graphs showing radiation pattern characteristics on the ZX plane of the plate-shaped inverted F antenna shown in FIG. 4, where FIG. 8A shows the present invention and FIG.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 housing 4 reception speaker 5 first surface of housing 14 plate-shaped inverted F antenna 15 metal foil 16 dielectric substrate 17 metal member (metal plate) 17a first surface of metal member 17b second surface of metal member 18 Rear of case

Claims (2)

[Claims] 1. A mobile communication device having a plate-shaped inverted F antenna in which a dielectric substrate having a metal foil formed on one surface thereof is provided in close contact with a metal member, wherein the plate-shaped inverted F antenna has a dielectric substrate. A mobile communication device, wherein the mobile communication device is arranged perpendicular to a first surface having at least a receiver of the housing of the mobile communication device and above the housing. 2. The mobile communication device according to claim 1, wherein the metal member is composed of a first surface on which the dielectric substrate is closely attached and a second surface perpendicular to the first surface.
A mobile communication device having a character shape, wherein the second surface is arranged along the back surface of the housing.