JP2001156532A - Antenna, and portable terminal provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna having a nearly equal mount area to that of a conventional antenna whose reception efficiency can be enhanced and to provide a portable terminal provided with it. SOLUTION: A radiating conductor 2 formed on a ground on a ground conductor plate 1 being a case of the portable terminal via dielectric body 4, a short- circuit plate 3 interconnecting the ground conductor plate 1 and a 1st side #1 of the radiating conductor 2, and a coaxial line 5 feeding the radiating conductor 2 are placed on the ground conductor plate 1. A flat part spread in an upper left direction of the radiating conductor 2 forms a 1st radiating part #a and a flat part spread in an upper right direction of the radiating conductor 2 forms a 2nd radiating part #b, and the 1st side #1 is placed nearly orthogonally to the length direction of the portable terminal. Using the 1st and 2nd radiating parts #a, #b can receive radio waves in different polarized wave directions without a polarization loss.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a built-in antenna for a portable terminal typified by a portable telephone, and a small and thin antenna for improving the reception efficiency by realizing the dual use of polarization, and the same. Mobile terminal.

[0002]

2. Description of the Related Art In land mobile communication using the L band represented by a portable telephone, a vertically polarized radio wave is radiated from a base station. By reflection and scattering from surrounding buildings and trees,
Various linearly polarized radio waves arrive at the mobile terminal.
When these arriving radio waves are divided into vertical and horizontal polarization components, the horizontal polarization is generally at a level lower than the vertical polarization by about -6 dB, but equivalently, both polarizations arrive. I have.

[0003] A portable terminal has a built-in antenna as shown in FIG. That is, a radiation conductor 82 is formed on a ground conductor plate 81 which is a casing of a portable terminal via a dielectric 83, and one end thereof is connected to the ground conductor plate 81 by a short-circuit plate 84 and short-circuited. Further, a coaxial line 85 that feeds the radiation conductor 82 is provided.

[0004] However, the portable terminal is used in a state of being inclined about 60 degrees from the vertical axis. Therefore, FIG.
When a one-side short-circuited microstrip antenna shown in FIG. 1 is used, a cos component and a sin component of vertically and horizontally polarized waves are received. For this reason, there is a problem that generally called polarization loss occurs and reception efficiency is reduced.

[0005] This will be described with reference to FIG. 9.
Receive the most efficiently. However, when the radio wave arriving at the terminal is divided into a vertical polarization component 93 and a horizontal polarization component 94, the built-in antenna 91 outputs the cos component 95 of the vertical polarization component 93.
And the sine component 96 of the horizontal polarization component 94. For this reason, a polarization loss occurs.

[0006]

As described above, when the incoming radio wave is decomposed into vertical and horizontal polarization components, the conventional built-in antenna for a portable terminal has a problem that the cos component and the s
Since the in component is to be received, there is a problem that polarization loss occurs and reception efficiency is reduced.

An object of the present invention is to provide an antenna which solves the above-mentioned problems of the prior art, improves the reception efficiency with an antenna area substantially equal to that of the conventional antenna, and a portable terminal provided with the same. With the goal.

[0008]

According to a first aspect of the present invention, there is provided an antenna according to the present invention, comprising: a grounding conductor plate; and an antenna facing the grounding conductor plate and extending in a first direction. A radiation conductor having a first planar portion and a second planar portion extending in a second direction; a short-circuit plate for connecting the radiation conductor to a ground conductor plate; and a power supply unit for supplying power to the radiation conductor. , The first plane portion and the second plane portion form a radiation section for receiving radio waves in different polarization directions.

According to the antenna having such a configuration, radio waves in different polarization directions can be received without polarization loss, and the polarization efficiency can be improved.

According to a second aspect of the present invention, in the antenna according to the first aspect, the feeding unit feeds the first and second plane portions from one feeding unit.

According to a third aspect of the present invention, in the antenna according to the first aspect, the feeding means has two feeding portions for feeding the first and second plane portions, respectively.

According to such a configuration, radio waves in different polarization directions can be received without polarization loss, and power supply to the first and second plane portions is separately controlled by the two power supply units. Therefore, polarization diversity reception can be performed.

According to a fourth aspect of the present invention, there is provided a portable terminal provided with the antenna according to the present invention, comprising: a ground conductor plate serving as a housing; and a first flat portion facing the ground conductor plate and extending in a first direction. A radiating conductor having a second plane portion extending in the second direction, a short-circuit plate for connecting the radiating conductor and the ground conductor, and a power supply unit for supplying power to the radiating conductor; The first planar portion forms a radiating portion that receives a substantially vertical polarization, and the second planar portion forms a radiating portion that receives a substantially horizontal polarization.

According to the portable terminal equipped with the antenna having such a configuration, it is possible to receive the vertically polarized wave and the horizontally polarized wave without any polarization loss, and to perform good communication with the base station. .

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a portable terminal provided with an antenna according to a first embodiment of the present invention.
FIG. 2 is a perspective view showing the configuration of the main part, and FIG. 2B is a plan view showing the arrangement of the radiation conductor.

As shown in FIG. 1, a radiating conductor 2 formed on a grounding conductor plate 1 as a housing of a portable terminal via a dielectric 4, and a first of the grounding conductor plate 1 and the radiating conductor 2. It is composed of a short-circuit plate 3 that connects side # 1 and short-circuits, and a coaxial line 5 that feeds the radiation conductor 2.

Here, when the short-circuited first side of the radiating conductor 2 is set to # 1 and each side of the radiating conductor 2 is numbered clockwise, the radiating conductor 2 has the first side # 1 A part or the whole is short-circuited to the ground conductor 1, and the second side # 2 and the fourth side # 4, and the fifth side # 5 and the seventh side # 7 are parallel and the fourth side
Side # 4 and the fifth side # 5 are at right angles. Further, the third side # 3 and the fourth side # 4 are orthogonal, and the fifth side # 5 and the sixth side # 6 are also orthogonal. Further, the radiating conductor 2 is arranged on the housing (ground conductor plate) 1 so that the first side # 1 is orthogonal to the y-axis which is the longitudinal direction of the housing (ground conductor plate) 1. That is, the structure is symmetric with respect to the y-axis shown in FIG.

With such a configuration, the radiating conductor 2 has the first radiating portion #a formed by the flat portion extending to the upper left including the left portion of the short-circuited first side # 1. The second radiating portion #b is formed by a flat portion extending in the upper right direction including the right portion of the first side # 1 as shown in FIG.
As shown in (b), the first radiating portion #a is-
The polarization 6 in the 45-degree direction and the second radiating section #b become a polarization 7 in the 45-degree direction with respect to the y-axis, and the polarizations 6 and 7 are orthogonal to each other.

Considering the case where the housing 1 is inclined by 45 degrees in the x-axis direction, the first radiating section #a receives a vertically polarized radio wave and the second radiating section #b receives a horizontally polarized radio wave. To receive the radio waves. That is, by designing the antenna element having the radiating portions #a and #b to resonate at a predetermined frequency, vertical and horizontal polarized waves can be received most efficiently.

FIGS. 2A and 2B show contour lines of the electric field Ez between the ground conductor plate 1 and the radiation conductor 2 at the reflection frequency and the resonance frequency in the antenna configuration shown in FIG. 1, respectively.
2B, the resonance frequency is f, the length of the first side # 1 is L # 1, the length of the second side # 2 is L # 2, and the length of the third side # 3 is L # 3, the length of the sixth side # 6 is L # 6, the length of the seventh side # 7 is L # 7, the thickness of the dielectric 4 is h, and the permittivity of the dielectric 4 is εr, when the distance from the connection point between the fourth side # 4 and the fifth side # 5 to the feeding point by the coaxial line 5 is d, f = 1.32 GHz, L # 3 = L # 6 = 25. 0
mm, L # 2 = L # 7 = 38.0 mm, h = 5 mm, ε
r = 1.0, d = 7.0 mm, L # 1 = 28.28 mm
It is about the case of.

From this figure, the antenna of this embodiment is matched with the coaxial line 5 which is a feed line.
The electric field distribution on the third side # 3 and the sixth side # 6, which are the radiation ends of the first radiating section #a and the second radiating section #b, appears most strongly. Therefore, when the housing 1 is tilted by approximately 45 degrees, it can be understood that the antenna of this embodiment operates at a predetermined resonance frequency with both vertical polarization and horizontal polarization.

In the above case, the vertical and horizontal polarized waves are most efficiently received when the housing 1 is tilted by approximately 45 degrees. However, when the housing 1 is tilted by approximately 60 degrees. To
A configuration in which vertical and horizontal polarized waves are received most efficiently can also be adopted. To achieve such a configuration, as shown in FIG. 3, the radiation conductor 2 is arranged on the housing (ground conductor plate) 1 such that the first side # 1 is inclined by −15 degrees with respect to the x-axis. It should be fine.

Further, a housing (ground conductor plate) 1 of the radiation conductor 2
May be arranged so that the vertical and horizontal polarized waves are received most efficiently when the housing 1 is tilted at a predetermined angle, and is not limited to the above-described case, and various methods can be considered.

As a modification of this embodiment, FIG.
As shown in (a), the width of the first radiating portion #a (that is, the length of the sixth side # 6) and the width of the second radiating portion #b (that is, the length of the third side # 3) 4 and the antenna structure in which the length of the fourth side # 4 and the length of the fifth side # 5 are different as shown in FIG. 4B, a and the second radiating section #b operate with orthogonal linear polarization. Therefore, even with this antenna configuration, the reception efficiency can be improved. Further, by changing the length and width, the first radiating portion #a
And the resonance frequency of the second radiating section #b can be controlled, so that it is possible to achieve a wider band, a dual frequency, or the like. That is, the resonance frequency can be lowered by increasing the length, and the bandwidth can be widened by increasing the width.

Further, in the above description, the case where the second side # 2 and the fourth side # 4 and the fifth side # 5 and the seventh side # 7 are parallel has been described. Side # 2 and fourth side # 4, and fifth side # 5 and seventh side # 7 may not be parallel.

Further, a slit or a U-shaped slot can be provided on the radiation conductor 2 shown in FIG. That is, FIG.
(A) and (b) show modifications in which a slit 31 and a U-shaped slot 32 are provided on the radiation conductor 2 respectively. Also in this antenna configuration, the first radiating section #a and the second radiating section #b operate with orthogonal linearly polarized waves. Further, by providing the slit 31 and the U-shaped slot 32 on the radiation conductor 2, the current flowing on the radiation conductor 2 can be changed to lower the resonance frequency. Therefore,
The size of the antenna can be reduced.

FIG. 6 shows a modification in which the first side # 1 and the short-circuit plate 3 of the radiation conductor 2 shown in FIG. 1 are bent in the direction inside the radiation conductor. First side # 1b and eighth side 1a of radiation conductor 2
Of the short circuit plate 61b and the short circuit plate 6
1a, each is connected to a ground conductor plate (not shown). Also in this antenna configuration, the first radiating section #
a and the second radiating section #b operate with orthogonal linear polarization.
Also in this case, the length of the sixth side # 6 and the length of the third side # 3 of the radiation conductor 2 may be different, or the length of the fourth side # 4 and the length of the fifth side # 5 may be different. May be different,
A slit or a U-shaped slot may be provided on the radiation conductor 2.

Next, a portable terminal equipped with an antenna according to a second embodiment of the present invention will be described.

In this embodiment, a short-circuit plate is inserted between the first radiating portion #a and the second radiating portion #b in the first embodiment, and the first radiating portion #a and the second For the radiating section #b,
They are configured so that they can be fed separately.

FIG. 7 is a plan view showing the configuration of the second embodiment.

FIG. 3A shows a straight line (over the entire line) connecting a connection point between the fourth side # 4 and the fifth side # 5 and an arbitrary point on the first side # 1. ) And a ground conductor plate (not shown) are connected by a short-circuit plate 71 and short-circuited. The first radiating section #a and the second radiating section #b are configured so that power is supplied by the coaxial lines 5a and 5b, respectively.

FIG. 4B shows the short-circuited first side # 1b and eighth side # 1a of the radiation conductor 2.
, A portion of a straight line (over all) connecting the connection point of the fourth side # 4 and the connection point of the fifth side # 5, and a ground conductor plate (not shown) are connected by a short-circuit plate 71. Has been short-circuited.
The first radiating section #a and the second radiating section #b are configured so that power is supplied by the coaxial lines 5a and 5b, respectively.

The housing (ground conductor plate) 1 of the radiation conductor 2
In the same manner as in the first embodiment, when the housing 1 is tilted at a predetermined angle, vertical and horizontal polarized waves may be received most efficiently.

In the case of the second embodiment, the coaxial line 5 for feeding power to the first radiating section #a and the second radiating section #b
a, since the coaxial line 5b is provided, the first radiating section #a
And the second radiating section #b can be separately controlled, so that diversity transmission and reception of vertically polarized waves and horizontally polarized waves can be performed.

Therefore, for example, when an incoming radio wave from a base station is received, the reception is performed with diversity, and the better one or both are combined, and when transmitting to the base station, the reception state is changed. Power can be supplied only to the better antenna element.

Also, in the second embodiment, as in the first embodiment, the sixth side # of the radiation conductor 2
6 may be different from the length of the third side # 3, or the length of the fourth side # 4 may be different from the length of the fifth side # 5. May be provided.

In each of the above embodiments, coaxial power supply has been described as a power supply method, but power supply by a strip line, electromagnetic coupling, or the like can be used.

Further, in each of the above embodiments, the radiation conductor 2
Is a polygon having straight sides, but the shape of the radiation conductor 2 is not limited to this, and has a plane portion extending in the first direction and a plane portion extending in the second direction. If so, various shapes composed of a combination of curves and straight lines can be used.

[0040]

According to the present invention, it is possible to solve the problem that the reception efficiency, which is the polarization loss that occurs in the conventional built-in antenna for a terminal, is reduced. By providing a slit or a U-shaped slot, it is possible to further reduce the volume of the antenna, and it is possible to further reduce the size and cost.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams showing a configuration of a portable terminal provided with an antenna according to a first embodiment of the present invention, wherein FIG. 1A is a perspective view showing a configuration of a main part thereof, and FIG. The top view showing a state.

FIGS. 2A and 2B are diagrams showing characteristics of the antenna according to the first embodiment of the present invention, wherein FIG.
(B) is a diagram showing the electric field distribution.

FIG. 3 is a plan view showing an arrangement of radiation conductors according to a modification of the first embodiment.

FIG. 4 is a plan view showing a configuration of a main part of a modified example of the first embodiment.

FIG. 5 is a plan view showing a configuration of a main part of a modification of the first embodiment.

FIG. 6 is a perspective view showing a configuration of a main part of a modification of the first embodiment.

FIG. 7 is a plan view showing a configuration of a mobile terminal provided with an antenna according to a second embodiment of the present invention.

FIG. 8 is a perspective view showing a configuration of a conventional example.

FIG. 9 is a diagram for explaining that a polarization loss occurs.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Grounding conductor plate (casing) 2 ... Radiation conductor 3, 61, 61a, 61b, 71 ... Short-circuit plate 4 ... Dielectric 5, 5a, 5b ... Coaxial line 6, 7 ... Polarization 31 ... Slit 32 ... U-shape Mold slot

Claims (4)

[Claims] 1. A ground conductor plate, and opposed to the ground conductor plate,
A radiation conductor having a first plane portion extending in a first direction and a second plane portion extending in a second direction; a short-circuit plate connecting the radiation conductor to the ground conductor plate; An antenna, comprising: a power supply unit configured to supply power, wherein the first planar portion and the second planar portion form a radiation unit that receives radio waves having different polarization directions. 2. The antenna according to claim 1, wherein the feeding unit feeds the first and second planar portions from one feeding unit. 3. The antenna according to claim 1, wherein said feeding means has two feeding portions for feeding the first and second plane portions, respectively. 4. A radiation conductor having a ground conductor plate serving as a housing, a first plane portion facing the ground conductor plate and extending in a first direction, and a second plane portion extending in a second direction. A short-circuit plate for connecting the radiation conductor to the ground conductor; and a power supply unit for supplying power to the radiation conductor, wherein the first plane portion is substantially vertically polarized when the housing is tilted. A portable terminal equipped with an antenna, wherein a radiating portion for receiving the horizontal polarization is formed, and the second plane portion forms a radiating portion for receiving the substantially horizontal polarization.