JP2001230622A - Antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna, capable of changing characteristics by controlling external conditions. SOLUTION: Antenna elements 10 and 11 of a dipole antenna 1 are composed of semiconductors. When the antenna elements 10 and 11 are irradiated with a light from a light irradiating part 2, the antenna 1 functions as an antenna. When irradiation is stopped, the antenna 1 is not functioned as antenna.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna for transmitting or receiving electromagnetic waves.

[0002]

2. Description of the Related Art In a conventional antenna, there is no known antenna that changes the characteristics of the antenna itself by controlling external conditions.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an antenna whose characteristics can be changed by controlling external conditions.

[0004]

An antenna according to claim 1 is an antenna provided with an antenna element, wherein at least a part of the antenna element is made of a material whose resistance value changes depending on external conditions. Configuration. Here, the antenna element refers to a part that receives or transmits an electromagnetic wave in the antenna,
For example, it refers to a dipole part in a dipole antenna, a loop part in a loop antenna, and the like.

[0005] An antenna according to a second aspect is the antenna according to the first aspect, wherein the material is a semiconductor.

According to a third aspect of the present invention, there is provided the antenna according to the second aspect, wherein the external condition is light irradiated to the material, and the light is a wavelength capable of exciting a carrier in the semiconductor from a valence band to a conduction band. Ingredients were included.

According to a fourth aspect of the present invention, in the antenna according to the third aspect, the light is laser light.

[0008] The antenna according to the fifth aspect is the antenna according to the first to fourth aspects.
In the antenna according to any one of the above, the antenna element is an antenna element in a linear antenna or a plate antenna. Here, a linear antenna or a plate antenna refers to an antenna having a linear or plate antenna element such as a dipole antenna, a monopole antenna, a loop antenna, a helical antenna, a spiral antenna, etc. It does not include an aperture antenna.

The antenna according to claim 6 is the antenna according to claims 1-4.
In the antenna according to any one of the above, the antenna element is a closing member that closes all or a part of the opening of the aperture antenna. Here, an aperture antenna is an antenna such as a slot antenna, a horn antenna, or a reflector antenna that transmits and receives electromagnetic waves propagating through a dielectric through an aperture directed to the dielectric such as air or vacuum. Name.

The antenna according to claim 7 is the antenna according to claims 2-6.
5. The antenna according to claim 1, wherein the semiconductor is germanium.

An antenna system according to an eighth aspect of the present invention includes an antenna and a light irradiating unit, wherein the antenna includes an antenna element, and at least a part of the antenna element is formed of a semiconductor whose resistance value changes by light irradiation. The light irradiation unit is configured to irradiate light toward the semiconductor, and the light includes a wavelength component that can excite carriers in the semiconductor from a valence band to a conduction band. It has become.

An antenna system according to a ninth aspect includes an antenna and a light irradiating unit, wherein the antenna is common to a plurality of antenna elements forming an array antenna and to all or a part of the plurality of antenna elements. A feeder connected to the feeder, at least a part of the plurality of antenna elements to which the feeder is connected is formed of a semiconductor having a resistance value changed by light irradiation, and the light irradiation unit is connected to the semiconductor. The semiconductor device is configured to irradiate light toward the semiconductor device, and the light includes a wavelength component that can excite carriers in the semiconductor from a valence band to a conduction band.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An antenna system according to a first embodiment of the present invention will be described with reference to FIG. This antenna system can be used for both reception and transmission due to the reversibility of the antenna.

The antenna system of this embodiment is
It has a tener 1 and a light irradiator 2. Antenna 1 is a wire
Constitute a dipole antenna as a type of antenna
Antenna elements 10 and 11 and these antennas
Feeder (feed line) connected to elements 10 and 11
Roads) 12 and 13. Antenna element 1
The whole of 0.11 is "The resistance value changes due to light irradiation.
Composed of intrinsic germanium
ing. The light irradiation unit 2 includes an optical fiber and an optical system (not shown).
), And where the data is transmitted by optical fiber.
The constant power laser light is transmitted through the optical system to the antenna element.
To be able to irradiate almost the whole of the
I have. Here, as the power and wavelength of the laser light,
Germanium carriers are excited to make the antenna element
Is sufficient to obtain sufficient conductivity. concrete
Depends on the design conditions.
About 0.5 μm to 1.6 μm in wavelength, 0.1 W in power
/ Cm²~ 1.0W / cm ²I think the degree is appropriate
It is. Feeders 12 and 13 have terminals 12a and 13a.
Input or output required as an antenna.
It has become so.

Next, the operation of the antenna system according to this embodiment will be described. When it is desired to operate the antenna 1 as an antenna, the light irradiation unit 2 irradiates the antenna elements 10 and 11 with laser light. This allows
In the semiconductor germanium forming the antenna elements 10 and 11, carriers are excited from the valence band to the conduction band. Of course, in this case, the wavelength of the light needs to be such that the excitation of the carrier can occur. Then, the resistance value of the antenna element in the portion irradiated with light decreases and approaches the property of the conductor, so that the antenna element can function as an antenna. Here, in the antenna element, the portion where the resistance value decreases is only the portion irradiated with light, that is, only the surface portion, but the antenna element can be operated only with the surface portion. Power may be supplied by irradiating light so that the resistance value decreases to the junction with the feeders 12 and 13, but the present invention is not limited to this. Even in a state where the resistance value of the joint between the antenna elements 10 and 11 and the feeders 12 and 13 is high, input and output are possible by electromagnetic coupling between the two.

On the other hand, when it is not desired to operate the antenna 1 according to this embodiment as an antenna, the light irradiation unit 2 does not irradiate the antenna elements 10 and 11 with light. Then, light having a wavelength necessary for exciting the carriers does not hit the semiconductor, and the resistance values of the antenna elements 10 and 11 become sufficiently high. As a result, the antenna 1 has a low gain and does not substantially function as an antenna. Note that in order to ensure non-operation, it is desirable to block external light so that it does not hit the antenna elements 10 and 11 during non-operation.

Therefore, according to the antenna of the present embodiment, whether the antenna elements 10 and 11 function as antennas can be controlled by controlling the external condition of light irradiation.

Further, in this embodiment, since laser light is used as light, there is an advantage that carriers of a semiconductor can be efficiently excited with small power.

Next, a second embodiment of the antenna system according to the present invention will be described with reference to FIGS. In the description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The second embodiment differs from the first embodiment in that a slot antenna as an aperture antenna is used as an antenna element constituting the antenna 1 instead of a dipole antenna. . In the present embodiment, the opening (slot) 20 is used as an antenna element.
a (see FIG. 3) and a plate-shaped closing member 21 for closing the entire surface of the opening 20a. As a material of the closing member 21, germanium is used as in the first embodiment. Lecher wires 22 and 23 as feeders are connected to the back side of the conductor plate 20 near the opening 20a. The Rechel wires 22 and 23 are terminals 22a and 2 for input or output.
3a.

Next, the operation of the antenna system according to the second embodiment will be described. When it is not desired to operate the antenna 1 as an antenna, the light irradiation unit 2 irradiates the closing member 21 with laser light. As a result, the resistance value of the closing member 21 decreases and approaches the conductor. Then, the electric and magnetic fields of the electromagnetic wave transmitted through the opening 20a become small, and it becomes impossible to obtain a sufficient gain as an antenna. That is, the antenna substantially does not function.

On the other hand, when it is desired that the antenna 1 be operated as an antenna,
Is not irradiated with laser light. This allows
The resistance value of the closing member 21 increases and approaches the property of the dielectric. Then, the electromagnetic wave is easily transmitted through the closing member 21, and the electromagnetic wave can be operated in the same manner as a well-known slot antenna by the action of the opening 20a.

Therefore, according to the antenna of the second embodiment, on the contrary to the first embodiment, it is possible to perform control such that the function as the antenna can be stopped by irradiating light.

Although the slot antenna is used as the aperture antenna in the second embodiment, another aperture antenna such as a horn antenna may be used.
The closing member 21 used for the aperture antenna may have a configuration capable of concealing (blocking) all or a part of the aperture of the aperture antenna in the radio wave transmission / reception direction. Therefore, as the positional relationship between the closing member 21 and the opening, in addition to the configuration in which the closing member 21 is in contact with the opening, the closing member 21 may be separated from the opening in the outer direction, or may be disposed inside the opening. Is also good.

Next, a third embodiment of the antenna system according to the present invention will be described with reference to FIG. In the description of the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The light irradiating unit 2 in the third embodiment sets a range in which the laser beam is irradiated from the light irradiating unit 2 to the antenna elements 10 and 11 as a range D.
It is possible to select as ₁ and range D _2.

Next, the operation of the antenna system according to the third embodiment will be described. Basic operation is first
This is the same as that of the embodiment. In the antenna 1 according to the third embodiment, the length of a portion that operates as an antenna, that is, the resonance wavelength of the antenna can be changed by switching the range of irradiation with laser light. Therefore, there is an advantage that the frequency of the electromagnetic wave having the maximum gain in reception or transmission can be switched as required. That is, with the configuration as in this embodiment, it is possible to obtain a high-gain antenna in a wide band. Needless to say, the irradiation range can be changed not only in two stages but also in multiple stages or continuously.

Next, a fourth embodiment of the antenna system according to the present invention will be described with reference to FIG. In the description of the fourth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The antenna 1 in the fourth embodiment is a so-called array antenna. That is, a plurality of a pair of antenna elements 10 and 11 constituting a dipole are arranged. Each antenna element 10 and 11 has
The feeders 12 and 13 and the load resistor 14 are connected.

Next, the operation of the antenna system according to the fourth embodiment will be described. In this antenna system, since the same feeders 12 and 13 and the load resistor 14 are connected to each of the antenna elements 10 and 11, input or output cannot be performed for each antenna element, and the antenna functions as a normal array antenna. do not do.
However, in the present embodiment, it is assumed that only a pair of antenna elements 10 and 11 that are to function as an antenna are irradiated with laser light, and the other elements are not irradiated. Next, an antenna element 1 for irradiating a laser beam
0.11 is sequentially changed. According to the configuration of the antenna 1 according to the present embodiment, it is possible to function as an array antenna in this manner. In a normal array antenna, wiring of a feeder and electronic or mechanical switching for input or output must be performed independently for each element, and the configuration is extremely complicated. On the other hand, in the antenna system of the present embodiment, a plurality of antenna elements can be connected in parallel to a common feeder, and the configuration is simplified. Also, without the need for electronic or mechanical switching as in the past,
The element that functions as an antenna can be switched simply by changing the element that emits light. In addition, in the antenna 1 of the present embodiment, by making the resistance value of the load resistor 14 equal to the value of the characteristic impedance of the feeder, reflection can be eliminated and the operation can be stabilized. The array antenna as in the fourth embodiment is
It can also be used as an antenna array for an image sensor using electromagnetic waves, for example, microwaves. further,
Switching of the irradiation angle and range in the light irradiation unit 2 can be easily realized by using a well-known optical system such as a lens or a polygon mirror. In the present embodiment, the elements are arranged one-dimensionally in the x direction, but may be arranged two-dimensionally in the xy direction.

Next, a fifth embodiment of the antenna system according to the present invention will be described with reference to FIG. In the description of the fifth embodiment, the description of the configuration common to the first embodiment will be omitted. The antenna 1 according to the fifth embodiment is a so-called electromagnetic coupling antenna. The antenna 1 mainly includes an antenna element 30 forming a dipole, a strip line 31 formed on an upper surface of a dielectric substrate 32, and a ground plane 33 mounted on the back surface of the substrate 32. The antenna element 30 is formed in a plate shape, and
2 is attached by an adhesive. That is, instead of being connected to the strip line 31 via a conductor such as solder, the connection is made via a dielectric layer such as an adhesive or air. Antenna element 3
0 is the antenna element 10 in each of the above embodiments.
・ Similar to 11 is made of semiconductor.

Next, the operation of the antenna system according to the fifth embodiment will be described. Also in this antenna system, as in the first embodiment, the antenna element 30 can be operated as an antenna by irradiating the antenna element 30 with laser light. Antenna element 3
Since 0 and the strip line 31 are electromagnetically coupled,
At a relatively high frequency, the impedance between the two becomes sufficiently low for practical use, and input / output as an antenna can be performed via the strip line 31. When it is not desired to operate as an antenna, irradiation of laser light may be stopped. This is also the same as in the first embodiment. Also in the fifth embodiment, an array antenna similar to that of the fourth embodiment can be formed by using a plurality of antenna elements 30 and electromagnetically coupling them to the strip line 31.

In each of the above embodiments, a dipole antenna or a slot antenna has been described as an example. However, the present invention is not limited to this, and an antenna using a property that an object used as an antenna element is a conductor or a dielectric is used. The present invention can be applied to any antenna that exhibits the function described above. For example, the present invention is applicable to various antennas such as a monopole antenna, a loop antenna, a Yagi antenna, and a horn antenna. By irradiating the antenna elements of these antennas with light, their properties can be switched between a conductor and a dielectric, thereby controlling whether or not to operate as an antenna.

In each of the above embodiments, germanium, which is an intrinsic semiconductor, is used as a semiconductor. However, the present invention is not limited to this. For example, intrinsic silicon or other intrinsic semiconductors, impurity semiconductors, compound semiconductors, cadmium sulfide (CdS), etc. ,
A material whose resistance value changes with light can be used.

Further, in each of the above embodiments, the entire antenna element is made of a semiconductor. However, it is possible to operate as an antenna.

In each of the above embodiments, light is used as a condition for controlling the characteristics of the antenna. However, for example, if a material whose resistance changes with temperature is used, temperature can be used as the control condition. It is. In short, if the resistance of the antenna element changes according to external conditions,
The characteristics of the antenna can be controlled using the external conditions.

Further, in each of the above embodiments, the laser light is used as the external condition for controlling the characteristics of the antenna. However, the present invention is not limited to this. Light including a large number of wavelengths, for example, light such as an incandescent lamp is used. It is also possible. In short, it is only necessary that the light to be irradiated contains a substantially sufficient wavelength component capable of exciting the carrier to the conductor.

Further, in the drawings for describing each embodiment, the thickness and dimensions of the members are schematically illustrated for easy understanding.

The description of each embodiment is merely an example,
It does not show a configuration essential to the present invention. The material and structure of each member may be configured to achieve the purpose of the present invention.

[0037]

According to the first aspect of the present invention, there is provided an antenna including an antenna element, wherein at least a part of the antenna element is made of a material whose resistance value changes depending on external conditions. Therefore, the characteristics of the antenna itself can be changed by controlling the external conditions.

In the antenna according to the second aspect of the present invention, since the material is a semiconductor, the variation in the resistance value of the antenna element due to the variation in external conditions can be increased, and the characteristics of the antenna can be improved. It can vary greatly.

According to a third aspect of the present invention, there is provided the antenna according to the second aspect, wherein the external condition is light for irradiating a material, and the light is a wavelength capable of exciting a carrier in the semiconductor from a valence band to a conduction band. Since a component is included, a change in the resistance value of the antenna element due to light irradiation can be increased, and the characteristics of the antenna can be further changed.

In the antenna according to the fourth aspect, since the laser light is used in the antenna according to the third aspect, it is possible to efficiently change the characteristics of the antenna with light having a small power.

The antenna according to claim 7 is the same as the antenna according to claims 2-6.
In the antenna according to any one of the above, since the semiconductor is made of germanium, the resistance value largely fluctuates due to external conditions, for example, light irradiation, and the characteristics of the antenna can be efficiently changed.

An antenna system according to claim 8, comprising an antenna and a light irradiating section, wherein the antenna has an antenna element, and at least a part of the antenna element is formed of a semiconductor whose resistance value changes by light irradiation. The light irradiation unit is configured to irradiate light toward the semiconductor, and the light includes a wavelength component that can excite carriers in the semiconductor from a valence band to a conduction band. Therefore, whether or not the antenna operates as an antenna can be controlled by light irradiation.

According to a ninth aspect of the present invention, there is provided an antenna system including an antenna and a light irradiating unit, wherein the antenna is common to a plurality of antenna elements constituting an array antenna and to all or a part of the plurality of antenna elements. A feeder connected to the feeder, at least a part of the plurality of antenna elements to which the feeder is connected is formed of a semiconductor having a resistance value changed by light irradiation, and the light irradiation unit is connected to the semiconductor. It is configured to irradiate light toward the light, the light is configured to include a wavelength component that can excite carriers in the semiconductor from the valence band to the conduction band, for example, a microwave image sensor An array antenna to be used can be easily configured.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory diagram of an antenna system according to a first embodiment of the present invention.

FIG. 2 is a perspective view schematically showing an antenna structure used in an antenna system according to a second embodiment of the present invention.

FIG. 3 is a schematic explanatory view corresponding to a cross section taken along line AA of FIG. 2;

FIG. 4 is an explanatory view schematically showing a structure of an antenna used in an antenna system according to a third embodiment of the present invention.

FIG. 5 is an explanatory view schematically showing a structure of an antenna used for an antenna system according to a fourth embodiment of the present invention.

FIG. 6 is an explanatory view schematically showing a structure of an antenna used for an antenna system according to a fifth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 Light irradiation part 10 ・ 11 Antenna element 21 Closure member 30 Antenna element

Claims (9)

[Claims] 1. An antenna including an antenna element, wherein at least a part of the antenna element is made of a material whose resistance value changes depending on external conditions. 2. The antenna according to claim 1, wherein the material is a semiconductor. 3. The external condition is light irradiated on the material, and the light includes a wavelength component that can excite carriers in the semiconductor from a valence band to a conduction band. Item 2. The antenna according to Item 2. 4. The antenna according to claim 3, wherein the light is a laser light. 5. The antenna according to claim 1, wherein the antenna element is an antenna element in a linear antenna or a plate antenna. 6. The antenna according to claim 1, wherein the antenna element is a closing member that closes all or part of an opening of the aperture antenna. 7. The antenna according to claim 2, wherein the semiconductor is germanium. 8. An illumination device comprising an antenna and a light irradiator, wherein the antenna includes an antenna element, and at least a part of the antenna element is formed of a semiconductor whose resistance value changes by light irradiation. The antenna system, wherein the unit is configured to irradiate the semiconductor with light, and the light includes a wavelength component that can excite carriers in the semiconductor from a valence band to a conduction band. 9. An antenna comprising: an antenna; and a light irradiator, wherein the antenna includes a plurality of antenna elements constituting an array antenna, and a feeder commonly connected to all or a part of the plurality of antenna elements. At least a part of the plurality of antenna elements to which the feeder is connected is formed of a semiconductor whose resistance value changes by light irradiation, and the light irradiation unit irradiates light to the semiconductor. And the light is
An antenna system comprising a wavelength component capable of exciting carriers in the semiconductor from a valence band to a conduction band.