JP2000174553A - Portable telephone set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve radiation characteristics and to improve a diversity effect by arranging a loop-shaped built-in antenna at the central part of a printed circuit board so that the normal standing on the surface surrounded with the loop can be parallel with the direction of a whip antenna. SOLUTION: The antenna of a portable telephone set is composed of a printed circuit board 10, whip antenna 1 and linear loop antenna 3. Concerning the linear loop antenna 3, the linear material of metal is loop-shaped, and this antenna is arranged so that the loop shape can stand vertically to the surface of the board 1O and one side can be parallel to the short side of the board and can be almost in contact at the central part of the board 10. Namely, the normal standing on the surface surrounded with the loop of the linear loop antenna 3 is parallel with the direction of protruding the whip antenna 1. The linear loop antenna 3 has strong directional characteristics in the direction of null point of the whip antenna 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable telephone (including a PHS), which is a portable telephone, and more particularly to a portable telephone capable of improving the effect of diversity.

[0002]

2. Description of the Related Art In a radio system such as a mobile phone system, two or more antennas are appropriately arranged in a housing of a mobile phone to perform transmission / reception in order to improve transmission / reception sensitivity due to multipath fading or the like. Diversity.

[0003] The arrangement of an antenna of a conventional portable telephone will be described with reference to FIGS. FIG. 7 is an explanatory diagram showing an arrangement state of an antenna of a conventional mobile phone;
8 and 9 are explanatory diagrams showing the directivity characteristics of the antenna of the conventional mobile phone when the operating frequency is 820 MHz. The configuration related to the antenna of the conventional mobile phone includes a printed board 10 provided in a housing and a printed board 1.
A whip antenna 1 protruding outside the housing from 0;
The antenna is designed to have a polarization in the longitudinal direction (vertical) of the housing because the base station uses a vertically polarized wave and a built-in antenna 2 for diversity.

[0006] As shown in FIG. 7, the whip antenna 1 is configured to protrude in the housing along an extension of one side in the longitudinal direction of the printed circuit board 10. In FIG. 7,
The printed circuit board 10 has a size of 120 × 35 mm,
Whip antenna 1 is 90 mm from printed circuit board 10
Only the protrusion is shown. In the following description, a normal direction standing on the surface of the printed circuit board 10 is defined as an X axis, a short side direction of the printed circuit board 10 is defined as a Y axis, and a longitudinal direction of the printed circuit board 10 is defined as a Z axis. On the Z axis, when the right-handed screw is turned from the positive direction of the X axis to the positive direction of the Y axis, the direction in which the screw advances is positive.

As shown in FIG. 8, the whip antenna 1 has 0 ° and 180 ° directions (Z-axis direction) in the θ direction on the YZ plane formed by the Y-axis and the Z-axis.
Is a null point, and has directivity characteristics that are maximum at ± 90 degrees (Y-axis direction), and has substantially the same directivity characteristics in all directions in the φ direction. , In the ZY plane, the rotation angle from the positive Z-axis direction to the Y-axis positive direction, and the φ-direction refers to the rotation angle direction from the X-axis positive direction to the Y-axis positive direction.

The built-in antenna 2 is formed by bending a material such as a metal wire to form a rectangle, a quadrilateral, or another loop (loop).
This is illustrated as a loop of m. In addition, built-in antenna 2
Is attached, for example, inside the housing facing the printed circuit board 10 so that the plane of the loop is parallel to the plane of the printed circuit board 10. In FIG. The illustration is such that the distance to the surface of the built-in antenna 2 is 5 mm.

In consideration of the fact that the portable telephone is to be used in the hand, the built-in antenna 2 is arranged above the center of the printed circuit board 10 to reduce the influence on the electromagnetic waves of the hand. It has become common practice.

[0008] As shown in FIG.
The directional characteristics are such that they become weaker in directions of approximately 0 degrees and 180 degrees (Z-axis direction) and become maximum in ± 90 degrees (Y-axis direction). In the φ direction, it has weak directional characteristics in all directions.

[0009]

However, in the above-mentioned antenna of the conventional portable telephone, the correlation between the antennas is large because the whip antenna 1 and the built-in antenna 2 are arranged close to each other. There is a problem that the effect of diversity is not sufficient.
There is a problem that the two antennas may be coupled to each other to cause deterioration of characteristics.

Further, when performing polarization diversity, the polarization of the built-in antenna is made different from the polarization of the whip antenna. However, in the conventional structure in which the built-in antenna is mounted above the center of the housing, these are not the same. However, there is a problem that the polarization cannot be made different. That is, in a mobile phone, the housing is small and a ground plate of a sufficient size cannot be secured, so that the current flowing through the ground plate greatly contributes to radiation, so that the polarization cannot be made different.

The present invention has been made in view of the above circumstances, and an antenna having any shape can be used as a built-in antenna.
Focusing on the fact that unless it is mounted in the center of the housing, the directional characteristics will be almost the same as a whip antenna protruding outside the housing, and it is possible to improve the radiation characteristics and improve the diversity effect It is intended to provide a telephone.

[0012]

According to a first aspect of the present invention, there is provided a whip antenna which is provided inside a housing, wherein the whip antenna is provided inside the housing. A mobile phone having a printed circuit board to be mounted and a built-in antenna provided in the housing, wherein the built-in antenna is an antenna formed in a loop shape, and is surrounded by the loop at a central portion of the printed circuit board. Characterized by being arranged so that the normal standing on the inclined surface is parallel to the direction of the whip antenna,
The effect of directivity diversity can be improved.

According to a second aspect of the present invention, there is provided a portable telephone according to the first aspect, wherein the built-in antenna is an antenna having a plate-like material formed in a loop. It is a built-in antenna that adjusts the ratio of the wave component to the cross-polarized component by the width of the plate, and the effect of diversity can be improved.

In the portable telephone according to the second aspect,
It is preferable that the board width of the built-in antenna be 10 mm to 20 mm.

According to a fourth aspect of the present invention, there is provided a whip antenna which projects to the outside of a housing, a printed circuit board provided inside the housing and to which the whip antenna is mounted. A mobile phone having a built-in antenna provided in the housing, wherein the built-in antenna is a helical antenna using a helical element in which a material of the antenna is wound in a coil shape, and is disposed close to the whip antenna. And a C loading switching element for switching between a terminal condition of open and a capacitor loaded condition is provided. The terminal condition can be switched to switch the main polarization plane of the helical antenna. Diversity can be achieved.

[0016]

Embodiments of the present invention will be described. The mobile phone according to the first embodiment of the present invention includes:
At the center of the printed circuit board, place the looped antenna
It is installed so that it stands perpendicular to the surface of the printed circuit board and one side of the loop is parallel to the short side of the printed circuit board and substantially touches the printed circuit board surface,
The effect of the diversity can be improved.

A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing the configuration of the antenna in the mobile phone according to the first embodiment of the present invention, and FIG. 2 is a diagram illustrating the directivity of the built-in antenna in the mobile phone according to the first embodiment of the present invention. FIG. 4 is an explanatory diagram showing characteristics. In FIG. 1, an example P of the feeding point is exaggerated. As shown in FIG. 1, the antenna of the mobile phone according to the first embodiment of the present invention includes a printed circuit board 10 having a substantially rectangular shape, and a housing extending in a direction extending one side in the longitudinal direction of the printed circuit board 10. It is composed of a whip antenna 1 projecting outward and a linear loop antenna 3. Here, the whip antenna 1 is
This is the same as the conventional one, and therefore has the directional characteristics shown in FIG.

The linear loop antenna 3 is obtained by processing an antenna material such as a metal into a linear shape and forming the linear material into a rectangular or quadrilateral shape or any other loop shape. Are arranged so that the loop shape stands in the vertical direction, the one side of the loop is parallel to the short side of the printed circuit board 10, and the center of the printed circuit board 10 (the printed circuit board 10 is
Because it is 0 mm x 35 mm, whip antenna 1
(At a position of about 60 mm from the mounting part). That is, the linear loop antenna 3
The normal standing on the surface surrounded by the loop is whip antenna 1.
Are parallel to the direction in which they protrude.

When the linear loop antenna 3 is installed in this manner, the directional characteristics of the linear loop antenna 3 are, as shown in FIG.
(In the axial direction), and has a weak directivity in the direction of ± 90 degrees (Y-axis direction).
That is, the θ direction has strong directional characteristics in the direction of the null point of the whip antenna 1,
It is easy to receive a signal polarized in the Z-axis direction.

The directional characteristics of the linear loop antenna 3 in the φ direction have weak directional characteristics in the directions of 0 degree and 180 degrees (X-axis direction), and in the directions of ± 90 degrees (Y-axis direction). And the directional characteristic of the whip antenna 1 in the φ direction has a weak directional characteristic substantially uniformly regardless of the direction. The directional characteristic 3 in the φ direction makes it easy to transmit and receive signals polarized in the Y-axis direction.

As described above, according to the arrangement of the antennas in the portable telephone according to the first embodiment of the present invention, the diversity transmission / reception is performed by combining whip antenna 1 and linear loop antenna 3 to obtain the whip antenna. 1 has excellent directivity characteristics of the linear antenna 3 in the Z-axis direction having no directivity, so that in the θ direction, a signal polarized in the Z-axis direction is polarized by the linear loop antenna 3 in the Y-axis direction. There is an effect that the effect of the directional diversity can be improved, for example, the wave signal is easily transmitted and received by the whip antenna 1. Also, the gain is greatly increased in the φ direction, and from this viewpoint, there is an effect that the effect of the polarization diversity can be improved.

Next, a mobile phone according to a second embodiment of the present invention will be described with reference to FIGS.
FIG. 3 is an explanatory diagram showing the configuration of the antenna of the mobile phone according to the second embodiment of the present invention. FIG. 4 is a diagram illustrating the directivity of the built-in antenna of the mobile phone according to the second embodiment of the present invention. FIG. 4 is an explanatory diagram showing characteristics. In FIG. 3, the feeding point P is exaggerated.

The portable telephone according to the second embodiment of the present invention uses a plate-shaped loop antenna 4 instead of the linear loop antenna 3, and can select a radiation characteristic having a high diversity effect depending on the plate width. Is what you do.

As shown in FIG. 3, the portable telephone according to the second embodiment of the present invention has a linear loop antenna 3 as a built-in antenna of the portable telephone according to the first embodiment shown in FIG. Is a plate-shaped loop antenna 4.

As shown in FIG. 3, the plate-shaped loop antenna 4 is made of a metal material such as metal instead of the linear loop antenna 3 as a built-in antenna of the portable telephone according to the first embodiment. It is processed into a short plate shape (so-called ribbon shape), and the ribbon-shaped material is bent to form a rectangular or quadrilateral shape or other cylindrical shape (loop). Opposes the surface of the printed circuit board 10 so that one side of the loop is substantially parallel to the short side of the printed circuit board 10 and the printed circuit board 1
It is installed so as to substantially contact zero. In other words, the normal that stands on the surface formed by the four sides of the plate-shaped loop antenna 4 is parallel to the direction in which the whip antenna 1 projects.

By doing so, the plate-like loop antenna 4
When the plate width W is 10 mm (corresponding to the example shown in FIG. 3), as shown in FIG. 4A, the case of the linear loop antenna 3 shown in FIG. Although the directional characteristics and the directional characteristics in the φ direction are substantially the same, the ratios of the magnitudes are different. Further, when the plate width W of the plate-shaped loop antenna 4 is set to 20 mm, it can be experimentally confirmed that the directivity characteristics as shown in FIG. Thus, the plate width W of the plate-like loop antenna is 10 mm to 20 m.
About m is appropriate, and broadly about 5 mm to 30 mm may be used.

In Table 1, when the operating frequency is 820 MHz, the rod-shaped loop antenna 3, the plate-shaped loop antenna 4 having a plate width W of 10 mm, and the plate width W are 20
The maximum gain in each of the θ and φ directions of each antenna when the plate-shaped loop antenna 4 mm and the built-in antenna are used as built-in antennas is listed.

[0028]

[Table 1]

As described above, according to the antenna of the portable telephone according to the second embodiment of the present invention, by changing the plate width of the plate-like loop antenna, the θ-direction (main polarization component) and the φ-direction By adjusting the gain of each polarization plane with (cross-polarization component), there is an effect that the radiation characteristic with the highest diversity effect can be easily selected. Regarding which radiation characteristics actually increase the dipersitiy effect,
It will be determined by experiment. In the case of a mobile terminal typified by a mobile phone, the use state (posture) is not constant, and it is not known which radio wave component arrives due to fading. When the selection can be made, there is an effect that sensitivity at the time of communication can be greatly improved.

Further, the portable telephone according to the third embodiment of the present invention uses a helical antenna in which a material of the antenna is wound in a coil shape as a built-in antenna.
The directional characteristics in the φ direction can be improved, and the effect of diversity can be improved.

An antenna of a mobile phone according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 5 is an explanatory diagram showing the configuration of the antenna of the mobile phone according to the third embodiment of the present invention. FIG. 6 is a diagram illustrating the directional characteristics of the antenna of the mobile phone according to the third embodiment of the present invention. FIG.

An antenna-related configuration in a mobile phone according to a third embodiment of the present invention is as shown in FIG.
It mainly includes a whip antenna 1, a helical antenna 5, a C loading switching element 6, and a printed circuit board 10.
In FIG. 5, the feeding point P is exaggerated.

The whip antenna 1 and the helical antenna 5 are both arranged to protrude in the longitudinal direction of the printed circuit board 10. In addition, whip antenna 1
Is the same as the conventional one.

The helical antenna 5 is, for example, a helical element (parasitic element) having a shape in which an antenna material such as a metal is processed into a linear shape, and the linearly processed material is wound into a coil shape at a certain interval in a cylindrical shape. ), Which are installed close to the whip antenna 1. Further, a C-load switching element 6 is provided at a contact point (terminal of the helical antenna 5) between the helical antenna 5 and the printed circuit board 10 so that the impedance can be switched.

The C loading switching element 6 includes a helical antenna 5
The terminal condition can be switched between an open state and a capacitor loaded state. Specifically, by switching a switch, the open state or the capacitor loaded state is switched. It is conceivable that this is the case.

Here, the directional characteristics of the helical antenna 5 will be described with reference to FIG. In FIG. 6, the winding length of the helical antenna 5 is set to approximately half wavelength, 7φ / 8 turns (turns), that is, 7 mm (diameter) × π × 8 (turns) = 176.
mm, and the capacitance of the capacitor when the capacitor is loaded is 1 pF. When the terminal condition of the helical antenna 5 is set to the open state, as shown in FIG. 6A, in the θ direction, 0 ° and 180 ° directions (Z-axis direction) are null points, and ± 90 ° directions. (Y-axis direction)
It has a strong directional characteristic. In the φ direction, the directional characteristics are weak in all directions. That is, when the terminal condition is set to the open state, the main polarization plane of the helical antenna 5 is in the θ direction.

When the terminal condition of the helical antenna 5 is a capacitor loaded state, in the θ direction, 0 ° and 180 ° directions (Z axis direction) are null points, and ± 90 ° directions (Y axis direction). ) Has a rather strong directional characteristic. Note that the gain in the θ direction is reduced by about 5 dB as compared with the case where the terminal condition is in the open state. Also, in the φ direction, the gain is improved by about 15 dB as compared with the case where the terminal condition is in the open state, and the directional characteristics are strong in all directions. Has the effect of realizing polarization plane diversity by combining diversity.

In the case of a mobile terminal such as a mobile phone, the attitude changes according to the use situation, and it is not known which radio wave arrives due to fading. Therefore, it is advantageous to realize the polarization plane diversity. It is believed that there is.

That is, according to the portable telephone according to the third embodiment of the present invention, the effect of uneven plane diversity can be improved and the sensitivity of communication can be greatly improved.

[0040]

According to the first aspect of the present invention, the built-in antenna is formed in a loop shape, and a normal standing on a surface surrounded by the loop in the center of the printed circuit board is parallel to the whip antenna. Since the mobile phones are arranged, the directional characteristics of the whip antenna and the built-in antenna are made different from each other, so that the effect of directional diversity can be improved.

According to the second aspect of the present invention, the built-in antenna is an antenna in which a plate-like material is formed in a loop, and the ratio of the main polarization component to the cross-polarization component is adjusted by the width of the plate. Since the portable telephone according to the first aspect is provided, there is an effect that the effect of diversity can be improved.

According to the fourth aspect of the present invention, the built-in antenna is a helical antenna using a helical element, and is disposed close to the whip antenna and switches between open terminal conditions and capacitor loaded state. Since the mobile phone is provided with the C loading switching element, the main polarization plane of the helical antenna can be switched by switching the terminal conditions, and there is an effect that polarization plane diversity can be performed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a method of arranging antennas in a mobile phone according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating directivity characteristics of a built-in antenna in the mobile phone according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating an arrangement of an antenna of a mobile phone according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram illustrating directivity characteristics of a built-in antenna of a mobile phone according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating an arrangement of an antenna of a mobile phone according to a third embodiment of the present invention.

FIG. 6 is an explanatory diagram illustrating directivity characteristics of an antenna of a mobile phone according to a third embodiment of the present invention.

FIG. 7 is an explanatory diagram illustrating an arrangement state of an antenna of a conventional mobile phone.

FIG. 8 is an explanatory diagram showing directivity characteristics of an antenna of a conventional mobile phone.

FIG. 9 is an explanatory diagram showing directivity characteristics of an antenna of a conventional mobile phone.

[Description of Signs] 1 ... whip antenna, 2 ... built-in antenna, 3 ... linear loop antenna, 4 ... plate loop antenna, 5 ... helical antenna, 6 ... C loading switching element, 10 ... printed circuit board

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mitsuru Muramoto 3-14-20 Higashinakano, Nakano-ku, Tokyo Kokusai Denki Co., Ltd. F-term (reference) 5J021 AA02 AA13 AB02 AB04 FA04 FA31 GA01 GA08 HA05 HA06 HA10 JA05 5K059 CC05 DD27

Claims (4)

[Claims] 1. A mobile phone comprising: a whip antenna protruding outside a housing; a printed circuit board provided in the housing, to which the whip antenna is attached; and a built-in antenna provided in the housing. Wherein the built-in antenna is an antenna formed in a loop shape, and is arranged at a central portion of the printed circuit board such that a normal standing on a surface surrounded by the loop is parallel to a direction of the whip antenna. Mobile phone. 2. The built-in antenna is an antenna in which a plate-like material is formed in a loop, and is a built-in antenna that adjusts a ratio between a main polarization component and a cross-polarization component by a width of the plate. The mobile phone according to claim 1. 3. The board width of the built-in antenna is 10 mm to 20 m.
3. The mobile phone according to claim 2, wherein m is m. 4. A mobile phone comprising: a whip antenna protruding outside a housing; a printed circuit board provided in the housing, to which the whip antenna is attached; and a built-in antenna provided in the housing. The built-in antenna is a helical antenna using a helical element in which the material of the antenna is wound in a coil shape, and is disposed close to the whip antenna, and whether the terminal condition is open or a capacitor loaded state is determined. A mobile phone provided with a C loading switching element for switching.