JP2003338783A - Antenna assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diversity antenna assembly which has a low cost and a small occupied space. <P>SOLUTION: When an X-type antenna 13 is fed from feed terminals 13a, 13b, currents flow in mutually orthogonal directions, resulting in that polarizing characteristics are mutually orthogonal in both feeding ways. Utilizing this effect, an antenna switch 14 can be controlled in accordance with a desired polarization of electromagnetic waves to enable the diversity with one antenna, thereby realizing a diversity antennal with a reduced occupied space at low cost. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device used for wireless communication or the like.

[0002]

2. Description of the Related Art Antenna diversity used in wireless communication is an effective means for removing the effects of fading from received signals. Generally, antennas are separately received by a plurality of antennas, and those signals are detected before or after detection. It is a method of synthesizing or switching automatically.
Typical examples of this method include spatial diversity and polarization diversity.

Spatial diversity utilizes the fact that the fading fluctuations at points distant from each other near the reception point are independent of each other. Usually, two or more antennas are spatially separated from each other and they are received separately and then the signals are combined or switched for use. Polarization diversity is a method in which a plurality of antennas having different polarizations are used and an antenna whose polarization plane matches that of incoming electromagnetic waves is received.

FIG. 9 shows an antenna configuration diagram of a conventional diversity radio apparatus. In FIG. 9, reference numeral 61 is a substrate on which the antenna is mounted. 62 is a ground plane formed on the substrate 61. Reference numerals 63 and 64 are antennas, 63a and 64a are power supply terminals that also serve as antenna supports, and 63b and 64b are ground terminals that also serve as antenna support. 65 is a power feeding terminal 63a or a power feeding terminal 64
It is an antenna switch that selects either one of a.
Reference numeral 66 is a transmission / reception circuit that performs signal processing for transmission / reception and control of the antenna switch 65. In this configuration, the antennas 63 and 64 are so-called inverted F antennas, and the two antennas perform diversity.

[0005]

A plurality of antennas are required to perform diversity, but in recent years, there has been a strong demand for miniaturization of radio devices, and the space allocated to the antennas has become smaller.

[0006] Therefore, an object of the present invention is to provide an antenna device which performs diversity with only one antenna element and saves space and has a merit in cost.

[0007]

According to the present invention, in order to realize a diversity antenna, one antenna element is provided with a plurality of feeding terminals.

[0008] According to the present invention, it is possible to provide an antenna apparatus which performs diversity with only one antenna element and saves space and has a cost advantage.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is an antenna having a ground terminal and a plurality of terminals for feeding, and a switch for selecting any one of the terminals for feeding. An antenna device that is connected to the switch and includes a transmission / reception circuit that performs signal processing for transmission / reception, control of the switch, and the like, and performs diversity by switching the switch. In addition, it has an effect that cost can be reduced.

According to a second aspect of the present invention, in the x-type antenna, a grounding terminal is provided at the tip of the adjacent antenna element to ground each, and power is supplied to any part of the adjacent antenna element. The antenna device according to claim 1, wherein the polarization diversity is performed by providing a terminal and switching a power feeding terminal with a switch, and the diversity can be performed with only one antenna element, which means that space can be saved and cost can be reduced. Have an effect.

The invention according to claim 3 of the present invention is the antenna device according to claim 2 in which the angle at which the antenna elements intersect in the x-shaped antenna is changed, and the radiation directivity of the antenna can be adjusted. Have.

The invention according to claim 4 of the present invention is the antenna device according to claim 2, wherein the length of adjacent antenna elements is slightly changed with respect to the wavelength in the x-shaped antenna, and the antenna has a wide band. It has the effect that it can be realized.

The invention according to claim 5 of the present invention is the antenna device according to claim 2 in which the lengths of adjacent antenna elements are asymmetrical in the x-shaped antenna, and they resonate at two different frequencies. It has the effect that

The invention according to claim 6 of the present invention is the antenna device according to claim 2, wherein the length and width of the antenna element are asymmetrical in the x-type antenna, and desired polarization characteristics are obtained. It has an effect that diversity can be performed.

The invention according to claim 7 of the present invention is the antenna device according to claim 2, wherein the antenna element on the open end side is bent in the x-shaped antenna, and a desired polarization characteristic is obtained. It has an effect that diversity can be performed.

The invention according to claim 8 of the present invention is an antenna device of an x-shaped antenna, comprising one feeding terminal and one or a plurality of ground terminals. Have the effect of exhibiting different polarizations.

According to a ninth aspect of the present invention, an L-shaped antenna is provided with one ground terminal provided at a bent portion and two power supply terminals provided so as to sandwich the previous ground terminal. The antenna device according to claim 1, wherein diversity is performed by switching a power feeding terminal with a switch, and since diversity can be performed with only one antenna element, there is an effect that space can be saved and cost can be reduced.

The invention according to claim 10 of the present invention is the antenna device according to claim 9 in which the angle at which the antenna elements intersect in the L-shaped antenna is changed, and the radiation directivity of the antenna can be adjusted. Have.

The eleventh aspect of the present invention is the antenna device according to the ninth aspect in which the lengths of the two antenna elements in the L-shaped antenna are slightly changed with respect to the wavelength. It has the effect of widening the characteristics.

A twelfth aspect of the present invention is the antenna device according to the ninth aspect in which the lengths of the two antenna elements are asymmetrical in the L-shaped antenna and resonates at two different frequencies. Have an effect.

The thirteenth aspect of the present invention is the antenna device according to the ninth aspect, in which the length and width of the two antenna elements are asymmetric in the L-shaped antenna, and a desired polarization characteristic is obtained. It has the effect that diversity can be obtained.

The invention according to claim 14 of the present invention is the antenna device according to claim 9, wherein the antenna element on the open end side is bent in the L-shaped antenna, and a desired polarization characteristic is obtained to obtain diversity. It has the effect of being able to perform.

According to a fifteenth aspect of the present invention, an L-shaped antenna is an antenna device having one feeding terminal and one or a plurality of ground terminals, and is an ordinary inverted F antenna. Have the effect of exhibiting different polarizations.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 8.

(Embodiment 1) FIG. 1 is a block diagram of an antenna device cited as a first embodiment of the present invention.
In FIG. 1, reference numeral 11 is a substrate on which an antenna is mounted.
Reference numeral 12 is a ground plane formed on the substrate 11. Reference numeral 13 is an X-shaped antenna. Reference numerals 13a and 13b denote power feeding terminals that also serve as a support for the X-shaped antenna 13, and 13c and 13b.
d also serves as a support for the x-shaped antenna 13,
Is a ground terminal for electrically connecting to the ground plane 12. Reference numeral 14 is an antenna switch that selects either the power supply terminal 13a or the power supply terminal 13b. 15 is a signal processing for transmission / reception and an antenna switch 14
It is a transmission / reception circuit that controls the above.

Now, assuming that the antenna switch 14 selects the power supply terminal 13a side to supply power, the current mainly flows in the direction of arrow A in FIG. On the other hand, antenna switch 1
If 4 selects the power supply terminal 13b side and power is supplied, the current mainly flows in the direction of arrow B in FIG. In this way, the case where power is supplied to the power supply terminal 13a and the case where power is supplied to the power supply terminal 13a
When power is supplied to b, currents flow in directions orthogonal to each other, so that the polarization characteristics in each case are also orthogonal. Utilizing this fact, if the antenna switch 14 is controlled so that the polarization characteristic of the desired electromagnetic wave and the polarization characteristic of the X-type antenna 13 match, it becomes possible to perform diversity with one antenna. As a method of matching the polarization characteristics, for example, the antenna switch 14 may be used for the power feeding terminal 13a.
When the antenna switch 14 is selected and the power supply terminal 1
By comparing the received electric field strengths when 3b is selected and selecting the feeding terminal having the larger received electric field strength for communication, the polarization characteristics of the desired electromagnetic wave and the polarization characteristics of the x-type antenna 13 are selected. Is equivalent to combining.

Further, in FIG. 2, it is possible to adjust the polarization characteristic of the antenna by setting the angles θ1 to θ4 of the adjacent antenna elements of the X type antenna 13 to appropriate values. For example, θ1 = θ3 = 60 °, θ2 = θ4 =
At 120 °, the current component in the horizontal direction of the paper surface increases and the current component in the vertical direction of the paper surface decreases, compared to the case of θ1 = θ2 = θ3 = θ4 = 90 °. Regarding the wave characteristics, the polarized waves on the left and right of the paper surface are strong, and the polarized waves on the top and bottom of the paper surface are weak. In this way, the polarization characteristics can be changed by adjusting the angles θ1 to θ4 of the antenna element.

Further, as shown in FIG. 3, it is possible to bend the antenna element and adjust the radiation directivity. In the shape of FIG. 3, the current in the vertical direction on the paper surface is larger than that in the non-bent x-shaped antenna, and the polarization in the vertical direction on the paper surface is stronger. The bending angle and length are not limited to those shown in FIG.
It can be freely determined to obtain desired characteristics.

Further, in order to make the characteristic of the X-type antenna 13 a wide band, for example, as shown in FIG.
Lengthen by L1. ΔL1 is a small value compared with the wavelength of the desired electromagnetic wave. If power is supplied to the power supply terminal 13a or the power supply terminal 13b in this state, the X-type antenna 13 operates as an antenna having a band widened to the low frequency side by ΔL1. If you want to extend the band to the high frequency side, ΔL
1 may be a negative value, that is, the length of the antenna element may be shortened. Further, if the absolute value of ΔL1 is increased, ×
Since the die antenna 13 has two resonance frequencies, it can be operated as a two-resonance antenna.

The band of the X type antenna 13 can also be adjusted by changing the widths W1 and W2 of the antenna elements. If the width W1 or W2 of the antenna element is increased, the band becomes wider, and conversely, the width W1 of the antenna element is increased.
Alternatively, narrowing W2 narrows the band.

As described above, by adjusting the angle, bend, length, and width of the X-shaped antenna, desired antenna characteristics can be obtained, and diversity can be achieved with one antenna. Even when only one feeding terminal is used without performing diversity, the angle, bend, length, width, etc. of the X-shaped antenna can be adjusted to have characteristics different from those of a general inverted F antenna. .

(Embodiment 2) FIG. 5 is a block diagram of an antenna device cited as a ninth embodiment of the present invention.
In FIG. 5, reference numeral 51 is a substrate on which the antenna is mounted.
Reference numeral 52 is a ground plane formed on the substrate 51. 53 is an L-shaped antenna. 53a and 53b are power supply terminals that also support the L-type antenna 53, and 53c are ground terminals that also support the L-type antenna 53 and electrically connect the L-type antenna 53 to the ground plane 52. 54 is a power supply terminal 53a or a power supply terminal 53b
It is an antenna switch that selects either one of the above. 55
Is a transmission / reception circuit that performs signal processing for transmission / reception, control of the antenna switch 54, and the like.

Now, assuming that the antenna switch 54 selects the power supply terminal 53a side to perform power supply, the current mainly flows in the direction of arrow C in FIG. On the other hand, antenna switch 5
4 selects the power supply terminal 53b side to supply power, the current mainly flows in the direction of arrow D in FIG. In this way, the case where power is supplied to the power supply terminal 53a and the case where power is supplied to the power supply terminal 53a
When power is supplied to b, currents flow in directions orthogonal to each other, so that the polarization characteristics in each case are also orthogonal. Utilizing this fact, if the antenna switch 54 is controlled so that the polarization characteristic of the desired electromagnetic wave and the polarization characteristic of the L-shaped antenna 53 match, it becomes possible to perform diversity with one antenna. As a method of matching the polarization characteristics, for example, the antenna switch 54 is used for the power feeding terminal 53a.
When the antenna switch 54 is selected
By comparing the received electric field strengths when 3b is selected and selecting the feeding terminal having the larger received electric field strength to perform communication, the polarization characteristics of the desired electromagnetic wave and the polarization characteristics of the L-type antenna 53 are compared. Is equivalent to combining.

Further, in FIG. 6, the polarization characteristic of the antenna can be adjusted by setting the angle θ5 of the adjacent antenna elements of the L-shaped antenna 53 to an appropriate value. For example, when θ5 = 60 °, the current component in the horizontal direction of the paper surface increases and the current component in the vertical direction of the paper surface decreases, compared to the case of θ5 = 90 °. As for the property, the polarized waves on the left and right sides of the paper become stronger, and the polarized waves on the upper and lower sides of the paper become weaker. In this way, the polarization characteristic can be changed by adjusting the angle θ5 of the antenna element.

Further, as shown in FIG. 7, it is possible to bend the antenna element and adjust the radiation directivity. In the shape of FIG. 7, the current in the vertical direction on the paper surface is larger than that of the L-shaped antenna without bending, and as a result, the polarized wave in the vertical direction on the paper surface is stronger. The bending angle and length are not limited to those shown in FIG.
It can be freely determined to obtain desired characteristics.

Further, in order to make the characteristics of the L-type antenna 53 have a wide band, for example, as shown in FIG.
Lengthen by L2. ΔL2 is a small value compared to the wavelength of the desired electromagnetic wave. When power is supplied to the power supply terminal 53a or the power supply terminal 53b in this state, the L-shaped antenna 53 operates as an antenna whose band is widened to the low frequency side by ΔL2. If you want to extend the band to the high frequency side, ΔL
2 may be a negative value, that is, the length of the antenna element may be shortened. Further, if the absolute value of ΔL2 is increased, L
Since the pattern antenna 53 has two resonance frequencies, it can be operated as a two-resonance antenna.

The band of the L-shaped antenna 53 can also be adjusted by changing the widths W3 and W4 of the antenna elements. If the width W3 or W4 of the antenna element is increased, the band becomes wider, and conversely, the width W3 of the antenna element is increased.
Alternatively, narrowing W4 narrows the band.

As described above, by adjusting the angle, bending, length, and width of the L-shaped antenna, desired antenna characteristics can be obtained, and diversity can be achieved with one antenna. Even when only one feeding terminal is used without performing diversity, the angle, bend, length, width, etc. of the L-shaped antenna can be adjusted to have characteristics different from those of a general inverted F antenna. .

Although the X-type and L-type antennas are shown as examples of the present invention, the present invention is not limited to these shapes.

[0040]

According to the present invention, one antenna is provided with a plurality of power feeding terminals, and the antenna has an antenna structure in which the polarization characteristic of the antenna changes depending on which of the power feeding terminals is selected, and the antenna is switched by a switch. By selecting any one of the terminals for power feeding, diversity can be performed with one antenna, so that the cost of the antenna can be suppressed and the occupied space can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an antenna device according to a first embodiment of the present invention.

FIG. 2 is a top view of the antenna according to the first embodiment of the present invention.

FIG. 3 is a top view of the antenna according to the first embodiment of the present invention.

FIG. 4 is a top view of the antenna according to the first embodiment of the present invention.

FIG. 5 is a configuration diagram of an antenna device according to a second embodiment of the present invention.

FIG. 6 is a top view of the antenna according to the second embodiment of the present invention.

FIG. 7 is a top view of the antenna according to the second embodiment of the present invention.

FIG. 8 is a top view of the antenna according to the second embodiment of the present invention.

FIG. 9 is an antenna configuration diagram of a conventional diversity wireless device.

[Explanation of symbols]

11, 51, 61 Substrate 12, 52, 62 Ground plane 13 x type antenna 53 L type antenna 63, 64 Inverse F antenna 13a, 13b, 53a, 53b, 63a, 64a Antenna power supply terminals 13c, 13d, 53c, 63b , 64b Antenna ground terminals 14, 54, 65 Antenna switches 15, 55, 66 Transmitter / receiver circuit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshinori Yonesu             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 5J021 AA01 AA02 CA06 DB04 FA31                       GA02 HA05 HA06 JA07                 5J045 AA05 AA12 AB05 DA08 HA06                       NA01                 5J046 AA01 AA04 AA07 AA12 AB13                       PA07                 5K059 CC05 DD24

Claims (15)

[Claims] 1. An antenna having a ground terminal and a plurality of power feeding terminals, a switch for selecting any one of the plurality of power feeding terminals, and a signal processing for transmission / reception and the signal processing connected to the switch. An antenna device, comprising: a transmission / reception circuit for controlling a switch, etc., and performing diversity with one antenna by switching the switch. 2. In an x-shaped antenna, grounding terminals are provided at the tips of adjacent antenna elements to be grounded respectively, and power feeding terminals are respectively provided at arbitrary portions of the adjacent antenna elements, and power feeding terminals are provided by a switch. 2. The antenna device according to claim 1, wherein polarization diversity is performed by switching between the two. 3. The antenna device according to claim 2, wherein in the X-shaped antenna, the directivity is adjusted by changing the angle at which the antenna elements intersect. 4. The antenna device according to claim 2, wherein in the X-shaped antenna, the band of the antenna is widened by slightly changing the length of adjacent antenna elements with respect to the wavelength. 5. The antenna device according to claim 2, wherein in the x-shaped antenna, adjacent antenna elements have asymmetrical lengths and resonate at two different frequencies. 6. The antenna device according to claim 2, wherein in the X-shaped antenna, a desired polarization characteristic is obtained by making the length and width of the antenna element asymmetrical to perform diversity. 7. The antenna device according to claim 2, wherein in the X-shaped antenna, a desired polarization characteristic is obtained by bending the antenna element on the open end side to perform diversity. 8. An antenna device, wherein an X-shaped antenna is provided with one feeding terminal and one or a plurality of grounding terminals, and exhibits a polarization different from that of a normal inverted F antenna. 9. An L-shaped antenna, comprising one grounding terminal provided at a bent portion and two power feeding terminals provided so as to sandwich the grounding terminal, and the power feeding terminal is switched by a switch. The antenna device according to claim 1, wherein the polarization diversity is performed by the following method. 10. The antenna device according to claim 9, wherein in the L-shaped antenna, the directivity is adjusted by changing the angle at which the antenna elements intersect. 11. An L-shaped antenna, wherein the lengths of two antenna elements are slightly changed with respect to wavelength,
The antenna device according to claim 9, wherein the antenna has a wide band. 12. The antenna device according to claim 9, wherein in the L-shaped antenna, the two antenna elements have asymmetrical lengths and resonate at two different frequencies. 13. The antenna device according to claim 9, wherein, in the L-shaped antenna, desired polarization characteristics are obtained by asymmetrical lengths and widths of the two antenna elements and diversity is performed. 14. The antenna device according to claim 9, wherein in the L-shaped antenna, a desired polarization characteristic is obtained by bending the antenna element on the open end side to perform diversity. 15. An antenna device comprising an L-shaped antenna, which is provided with one feeding terminal and one or a plurality of grounding terminals, and exhibits a polarization different from that of a normal inverted F antenna.