JP3432768B2 - Antennas for portable communication terminals - Google Patents

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 used for a wireless device, a mobile communication terminal, etc., and more particularly to an antenna configuration that enables effective diversity reception.

[0002]

2. Description of the Related Art FIG. 9 is a diagram showing a portable communication terminal device using a loop antenna as a diversity antenna.
Reference numeral 5 in the figure denotes a ground plane which is a ground conductor. This ground plane 5
It is composed of a plate-shaped body having a substantially rectangular shape. The loop antenna 1 is attached to the upper portion of the base plate 5 such that its loop surface 1a is perpendicular to the base plate 1.

A balanced / unbalanced conversion circuit 2 for converting between a balanced signal and an unbalanced signal is connected to the loop antenna 1, and the balanced / unbalanced conversion circuit 2 is connected to a ground plane 5. . In addition, the ground plate 5 on the side of the loop antenna 1
The power supply spring 4 is attached to the top so as to extend from the surface of the main plate 5. The monopole antenna 3 is attached to the tip of the feeding spring 4. The monopole antenna 3 is attached to the feed spring 4 so that its axial direction is substantially parallel to the surface of the base plate 5.

For example, in a portable radio such as a current mobile phone, an outer case which is a casing, a monopole antenna 3 and a feeding spring 4 are integrated. In this wireless device, the monopole antenna 3 is fed from the base plate 5 via the feeding spring 4. On the other hand, the loop antenna 1 is fed from the ground plane 5 via the balanced-unbalanced conversion element 2.

In the antenna having such a configuration, the loop antenna 1 is balanced-fed from the balance-unbalance conversion circuit 2.

On the other hand, the monopole antenna 3 is fed from the ground plate 5 via the feeding spring 4 to perform diversity reception with the loop antenna 1 so as to perform stable communication. .

[0007]

However, the loop antenna 1 is about 3 to 4 mm from the monopole antenna 3.
It is arranged on the main plate 5 which is distant from it. In this case, inter-antenna coupling occurs between the loop antenna 1 and the monopole antenna 3. The amount of coupling in this antenna coupling is −
It is very large, about 4 to -6 dB. If the amount of coupling is large in this way, the energy radiated from one antenna enters the other antenna, resulting in energy loss. There is a problem that the antenna gain becomes low due to this energy loss.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an antenna for a portable communication terminal, which is less affected by coupling between antennas and has high gain.

[0009]

The essence of the present invention is that, in a diversity antenna, a shield member is arranged between two antenna elements to reduce the amount of antenna coupling between both antenna elements, and equivalently both antenna elements. With a distance between them,
It is to realize a high gain diversity antenna.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An antenna for a portable communication terminal according to a first aspect of the present invention comprises a ground conductor formed of a plate and a loop surface perpendicular to the main surface of the ground conductor. A first antenna element that is provided on the ground conductor, a second antenna element that is provided on the ground conductor and that forms a diversity antenna with the first antenna element, and a second antenna element that is perpendicular to the loop surface. So that the first
An antenna extending from the ground conductor between the antenna element and the second antenna element and between the antenna element and the first antenna element;
A tenter capacitor is formed, and the first antenna element and the second antenna element are formed.
A shielding means for shielding the coupling between the antenna and the antenna ,
The configuration including is adopted.

An antenna for a portable communication terminal according to a second aspect of the present invention has a ground conductor composed of a plate-like body and a loop surface perpendicular to the main surface of the ground conductor, A first antenna element provided on a ground conductor; a second antenna element provided on the ground conductor and forming a diversity antenna with the first antenna element; One shield element is provided so as to face each other so as to sandwich one antenna element and to extend from the ground conductor.

According to these structures, since the capacitance is formed between the shielding means and the antenna element, the size of the antenna element itself can be reduced. As a result, the distance between both antenna elements can be increased, and the coupling between both antennas can be reduced.

In the antenna for portable communication terminal according to the third aspect of the present invention, in the first or second aspect, the shielding means is provided on the tip side thereof and extends to the first antenna element side. A configuration having a first plate is adopted.

An antenna for a portable communication terminal according to a fourth aspect of the present invention is the antenna for a portable communication terminal according to any one of the first to third aspects, wherein the shielding means is provided on the tip side thereof.
The configuration has a second plate that partially surrounds the antenna element.

According to these configurations, the first plate and the second plate also contribute to the increase of the antenna capacity, so that the size of the antenna element itself can be further reduced.
As a result, the distance between both antenna elements can be increased,
The coupling between both antennas can be reduced.

The antenna for portable communication terminals according to the fifth aspect of the present invention has a configuration in which the second antenna element is a monopole antenna.

A portable communication terminal device according to a sixth aspect of the present invention has a configuration including the portable communication terminal antenna according to any one of the first to fifth aspects.

According to this structure, since the small portable communication terminal antenna is mounted, it is possible to reduce the size of the entire apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment 1) FIG. 1 is a diagram showing a portable communication terminal apparatus according to Embodiment 1 of the present invention. In the figure, reference numeral 105 indicates a ground plane which is a ground conductor. This main plate 105
Is a plate-shaped body having a substantially rectangular shape. The loop surface 101a is provided on the upper surface of the main plate 105 as the main plate 1.
Loop antenna 10 so that it is perpendicular to 05
1 is attached. This loop antenna 101
Is provided on the side of the main plate surface not facing the human body (user).
Further, the loop antenna 101 is arranged away from the main surface (surface) of the ground plane 105 by an extremely short distance as compared with the wavelength, and the perimeter is set to approximately one wavelength or less.

A ground plate 105 on the side of the loop antenna 101
A power supply spring 104 is attached to the top of the ground plate 105 so as to extend from the surface of the ground plate 105. The monopole antenna 103 is attached to the tip of the feeding spring 104. The monopole antenna 103 is attached to the feeding spring 104 so that its axial direction is substantially parallel to the surface of the ground plate 105.

As described above, in the portable communication terminal antenna of this embodiment, the loop antenna 101 and the monopole antenna 103 constitute a diversity antenna.

A shield plate 106, which is a shield member, is provided on the main plate 105 between the loop antenna 101 and the monopole antenna 103. In the present embodiment,
The shield plate 106 is arranged on the surface of the main plate 105 so that its main surface is perpendicular to the surface of the main plate 105.

The size and material of the shield plate 106 are such that the amount of antenna coupling between the loop antenna 101 and the monopole antenna 103 can be reduced. For example, a metal shield plate or the like can be used as the shield plate 106.

In the portable communication terminal antenna having such a configuration, the monopole antenna 103 is fed from the ground plate 105 via the feeding spring 104. On the other hand, the loop antenna 101 is directly fed with power from the ground plane 105.

The loop antenna 101 fed from the ground plane 105 receives horizontal polarized waves substantially parallel to the loop plane. On the other hand, the monopole antenna 103 is fed from the ground plane 105 via the feeding spring 104, and the loop antenna 1
01 and the diversity reception are performed, and stable communication is performed.

FIG. 2 is a diagram for explaining the operation of the antenna for a portable communication terminal according to the embodiment of the present invention,
It is the figure seen from the A direction of FIG. As can be seen from FIG. 2, the loop antenna 101 forms a capacitance C1 with the base plate 105, and also forms a capacitance C2 with the shield plate 106.
Therefore, as the antenna capacity, the loop antenna 10
1 and the shield plate 106.

Therefore, in order to secure the required antenna capacity, the loop antenna 101 and the shield plate 106
Loop antenna 1
The size of 01 itself can be reduced.

That is, the loop antenna 1 in FIG.
It is possible to shorten the length L of 01. Therefore, the loop antenna 101 and the monopole antenna 103
The distance d between the antennas can be increased, and the coupling between both antennas can be reduced.

The shield plate 106 is the loop antenna 1
Since 01 and the monopole antenna 103 are shielded, the amount of antenna coupling between both antennas can be reduced.

As a result, it is possible to realize a high gain diversity antenna which is less affected by the coupling between the antennas.

(Second Embodiment) FIG. 3 is a diagram showing a portable communication terminal apparatus according to a second embodiment of the present invention. Figure 3
2, the same parts as those in FIG. 1 are designated by the same reference numerals as those in FIG.

In the antenna for portable communication terminal according to the present embodiment, the L-shaped shield plate 107 is used as a shield member.
Is used. The L-shaped shield plate 107 has a main surface 10 so that its main surface is perpendicular to the surface of the main plate 105.
5 shield plate body 107a disposed on the surface and the first plate 1 connected to the tip side of the shield plate body 107a
07b and.

The first plate 107b extends in the direction of the loop antenna 101 from the tip side of the shield plate body 107a, and the shield plate body 107a and the first plate 107.
The loop antenna 101 is partially surrounded by b.

By the L-shaped shield plate 107, the antenna capacitance becomes larger than that in the first embodiment, so that the length L of the loop antenna 101 can be further shortened. Therefore, it is possible to secure a wider distance d between the loop antenna 101 and the monopole antenna 103.

Further, since the L-shaped shield plate 107 shields the loop antenna 101 and the monopole antenna 103, the antenna coupling amount between both antennas can be reduced.

As a result, it is possible to obtain a highly gain diversity antenna that is more efficient and less affected by the coupling between the two antennas.

(Embodiment 3) FIG. 4 is a diagram showing a portable communication terminal apparatus according to Embodiment 3 of the present invention. Figure 4
2, the same parts as those in FIG. 1 are designated by the same reference numerals as those in FIG. 1 and their description is omitted.

In the mobile communication terminal antenna according to the present embodiment, the L-shaped shield plate 107 is used as a shield member.
Is used. The L-shaped shield plate 107 has a main surface 10 so that its main surface is perpendicular to the surface of the main plate 105.
5 shield plate main body 107a disposed on the surface and the second plate 1 connected to the tip side of the shield plate main body 107a
07b and.

The second plate 107c extends from the tip side of the shield plate body 107a toward the monopole antenna 103, and the shield plate body 107a and the second plate 1 are provided.
07c partially surrounds the monopole antenna 103.

Since the L-shaped shield 107 increases the antenna capacity as compared with the case of the first embodiment, the length L of the loop antenna 101 can be further shortened.
Therefore, it is possible to secure a wider distance d between the loop antenna 101 and the monopole antenna 103.

Further, since the L-shaped shield plate 107 shields the loop antenna 101 and the monopole antenna 103, the amount of antenna coupling between both antennas can be reduced.

As a result, it is possible to obtain a high-gain diversity antenna that is more efficient and less affected by the coupling between the two antennas.

(Embodiment 4) FIG. 5 is a diagram showing a portable communication terminal apparatus according to Embodiment 4 of the present invention. Figure 5
2, the same parts as those in FIG. 1 are designated by the same reference numerals as those in FIG.

In the portable communication terminal antenna according to the present embodiment, the T-shaped shield plate 108 serves as a shield member.
Is used. The T-shaped shield plate 108 has a main surface 10 so that its main surface is perpendicular to the surface of the main plate 105.
5 includes a shield plate main body 108a disposed on the surface, and first and second plates 108b and 108c connected to the tip end side of the shield plate main body 108a.

The first plate 108b extends in the direction of the loop antenna 101 from the tip side of the shield plate body 108a, and the shield plate body 108a and the first plate 108 are provided.
The loop antenna 101 is partially surrounded by b.

The second plate 108c extends in the direction of the monopole antenna 103 from the tip side of the shield plate body 108a, and the shield plate body 108a and the second plate 108c partially surround the monopole antenna 103. It is like this.

Since the T-shaped shield plate 108 increases the antenna capacity as compared with the case of the first embodiment, the length L of the loop antenna 101 can be further shortened.
Therefore, it is possible to secure a wider distance d between the loop antenna 101 and the monopole antenna 103.

Since the T-shaped shield plate 108 shields the loop antenna 101 and the monopole antenna 103, the amount of antenna coupling between both antennas can be reduced.

As a result, it is possible to obtain a highly gain diversity antenna that is more efficient and less affected by the coupling between the two antennas.

(Fifth Embodiment) FIG. 6 is a diagram showing a portable communication terminal device according to a fifth embodiment of the present invention. Figure 6
2, the same parts as those in FIG. 1 are designated by the same reference numerals as those in FIG.

In the portable communication terminal antenna according to the present embodiment, shield plates 106a and 106b arranged so as to sandwich the loop antenna are used as shield members. The shielding plates 106a and 106b are arranged on the surface of the main plate 105 such that their main surfaces are perpendicular to the surface of the main plate 105, and the main surfaces are opposed to each other.

The loop antenna 101 forms a capacitance with the ground plane 105, and also forms a capacitance with the shield plates 106a and 106b. Therefore, the antenna capacity can be considered as the loop antenna 101 and the shield plates 106a and 106b.

Therefore, in order to secure the required antenna capacity, the loop antenna 101 and the shielding plate 106
Since it is only necessary to secure with a and 106b, it is possible to reduce the size of the loop antenna 101 itself.

As described above, since the shield plates 106a and 106b increase the antenna capacitance as compared with the case of the first embodiment, the length L of the loop antenna 101 can be further shortened. Therefore, it is possible to secure a wider distance d between the loop antenna 101 and the monopole antenna 103.

Since the shield plates 106a and 106b shield the loop antenna 101 and the monopole antenna 103, the amount of antenna coupling between both antennas can be reduced.

As a result, it is possible to obtain a highly gain diversity antenna that is more efficient and less affected by the coupling between the two antennas.

(Embodiment 6) FIG. 7 is a diagram showing a portable communication terminal apparatus according to Embodiment 6 of the present invention. Figure 7
6, the same parts as those in FIG. 6 are denoted by the same reference numerals as those in FIG. 6 and their description is omitted.

In the portable communication terminal antenna according to the present embodiment, the loop antenna 10 is used as the shielding member.
The L-shaped shield plates 107 that face each other with 1 in between are used.
The L-shaped shield plate 107 has a shield plate main body 107a disposed on the surface of the main plate 105 and its shield plate main body 10 such that its main surface is perpendicular to the surface of the main plate 105.
The first plate 107b is connected to the tip side of 7a.

The first plate 107b extends in the direction of the loop antenna 101 from the tip end side of the shield plate body 107a, and the shield plate body 107a and the first plate 107 are provided.
The loop antenna 101 is partially surrounded by b.

As described above, since the L-shaped shield plate 107 increases the antenna capacitance as compared with the case of the first embodiment, the length L of the loop antenna 101 can be further shortened. Therefore, it is possible to secure a wider distance d between the loop antenna 101 and the monopole antenna 103.

Further, since the L-shaped shield plate 107 shields the loop antenna 101 and the monopole antenna 103, the amount of antenna coupling between both antennas can be reduced.

As a result, it is possible to obtain a highly gain diversity antenna that is more efficient and less affected by the coupling between the two antennas.

(Embodiment 7) FIG. 8 is a diagram showing a portable communication terminal apparatus according to Embodiment 7 of the present invention. Figure 8
6, the same parts as those in FIG. 6 are denoted by the same reference numerals as those in FIG. 6 and their description is omitted.

In the portable communication terminal antenna according to the present embodiment, the loop antenna 10 is used as the shielding member.
The L-shaped shield plate 107 and the T-shaped shield plate 108 that face each other with the No. 1 interposed are used. The L-shaped shield plate 107 has its main surface perpendicular to the surface of the main plate 105.
Shielding plate main body 107a disposed on the surface of the main plate 105
And a first plate 107b connected to the tip side of the shielding plate body 107a.

The first plate 107b extends in the direction of the loop antenna 101 from the tip end side of the shield plate body 107a, and the shield plate body 107a and the first plate 107b.
The loop antenna 101 is partially surrounded by b.

The main surface of the T-shaped shield 108 is the ground plane 1.
The shield plate main body 108a disposed on the surface of the main plate 105 and the first and second plates 108b and 108c connected to the tip end side of the shield plate main body 108a so as to be perpendicular to the surface of the shield plate 05. It is configured.

The first plate 108b extends in the direction of the loop antenna 101 from the tip end side of the shield plate body 108a, and the shield plate body 108a and the first plate 108 are provided.
The loop antenna 101 is partially surrounded by b.

The second plate 108c extends from the tip side of the shield plate body 108a toward the monopole antenna 103, and the shield plate body 108a and the second plate 108c partially surround the monopole antenna 103. It is like this.

Since the antenna capacity is increased by the L-shaped shield plate 107 and the T-shaped shield plate 108 as compared with the case of the first embodiment, the length L of the loop antenna 101 can be further shortened. Therefore, the loop antenna 1
It is possible to secure a wider distance d between 01 and the monopole antenna 105.

Since the L-shaped shield plate 107 and the T-shaped shield plate 108 shield the loop antenna 101 and the monopole antenna 103, the amount of antenna coupling between both antennas can be reduced.

As a result, it is possible to obtain a highly gain diversity antenna that is more efficient and less affected by the coupling between the two antennas.

The first to seventh embodiments of the present invention can be implemented in combination as appropriate.

The present invention is not limited to the above-described first to seventh embodiments, but can be implemented with various modifications.

[0075]

The antenna for portable communication terminal of the present invention is
A high gain diversity antenna can be realized by increasing the antenna capacity by the shield plate arranged between the antenna elements and reducing the antenna coupling amount between both antennas.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an antenna for a mobile communication terminal according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a coupled state of an antenna for a mobile communication terminal according to an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of an antenna for a mobile communication terminal according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of an antenna for a mobile communication terminal according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of an antenna for a mobile communication terminal according to a fourth embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of an antenna for a mobile communication terminal according to a fifth embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of an antenna for a mobile communication terminal according to a sixth embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of an antenna for a mobile communication terminal according to a seventh embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of a conventional antenna for a portable communication terminal.

[Explanation of symbols]

101 loop antenna 103 monopole antenna 104 connection spring 105 Ground plane (ground conductor) 106 Shield 107 L-shaped shield 108 T-shaped shield

─────────────────────────────────────────────────── ───Continued from the front page (56) References JP-A-11-27026 (JP, A) JP-A-2000-31721 (JP, A) JP-A-8-23218 (JP, A) Actual development Sho-63-81406 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01Q 1/00-1/52 H01Q 7/00 H01Q 9/30 H01Q 21/28

Claims (6)

(57) [Claims] 1. A first antenna element provided on the ground conductor, the ground conductor having a plate-like body, a loop surface perpendicular to the main surface of the ground conductor, and the ground. Between the first antenna element and the second antenna element, which is provided on the conductor and constitutes the diversity antenna with the first antenna element, and between the first antenna element and the second antenna element so as to be perpendicular to the loop surface. Extends from the ground conductor to form an antenna capacitance with the first antenna element
Of the first antenna element and the second antenna element
An antenna for a mobile communication terminal, comprising: a shielding unit that shields coupling between the antennas. 2. A grounding conductor formed of a plate-like body, a loop surface perpendicular to the main surface of the grounding conductor, and a first antenna element provided on the grounding conductor, and the grounding. A second antenna element, which is provided on the conductor and constitutes a diversity antenna with the first antenna element, is opposed to the second antenna element perpendicularly to the loop surface so as to sandwich the first antenna element, and from the ground conductor. An antenna for a portable communication terminal, comprising: an extending shielding unit. 3. The portable communication terminal according to claim 1, wherein the shielding means has a first plate which is provided on the tip side thereof and extends toward the first antenna element side. For antenna. 4. The shielding means includes a second plate which is provided on the tip side of the shielding means and which partially surrounds the second antenna element.
An antenna for a portable communication terminal according to any one of 1. 5. The antenna for a mobile communication terminal according to claim 1, wherein the second antenna element is a monopole antenna. 6. A mobile communication terminal device comprising the mobile communication terminal antenna according to claim 1. Description: