JP6249906B2 - Array antenna device - Google Patents

Description

  The present invention relates to an array antenna device having a function of a frequency selection plate.

  In recent years, plasma media has attracted attention as a material that can freely control the reflection, transmission, or absorption of electromagnetic waves, and the reflection, transmission, or absorption of electromagnetic waves can be achieved by controlling the frequency characteristics of the plasma medium with respect to electromagnetic waves. Many frequency selection plates that can control the frequency have been announced. The frequency selection plate is often used in combination with an antenna device.

The following Patent Document 1 discloses a frequency selection plate made of a dielectric having a hollow structure, and the frequency selection plate is an electrode for generating uniform plasma in the hollow of the dielectric. It has.
In this frequency selection plate, the transmission frequency of electromagnetic waves can be dynamically changed by adjusting the size of the slot opened on the upper surface of the dielectric.

Patent Document 2 below discloses a radome (radar dome) using plasma, and the radome has frequency selectivity of electromagnetic waves.
This frequency selectivity is realized by two frequency selection plates, and a gas is sealed in a honeycomb-shaped plasma sealing layer provided between the two frequency selection plates.
Plasma is generated from the gas by the electrodes extending along the honeycomb-shaped plasma encapsulating layer giving energy to each plasma encapsulating layer.
Even if plasma is generated from gas, if the plasma has a conductive nature with respect to the frequency of radio waves incident from the outside, the frequency of radio waves incident from the outside is temporarily assumed. Even if it is the transmission frequency of the radome, the radio wave is reflected by the plasma and cannot enter the interior.

Non-Patent Document 1 below discloses a band stop type frequency selection plate.
This frequency selection plate uses the conductive nature of plasma, and periodically arranges a plurality of fluorescent tubes capable of generating plasma so as not to pass a specific frequency. Yes.

JP 2013-225797 A US 2009/0109115 A1

T. Anderson et. Al., “Plasma Frequency Selective Surfaces,” IEEE Trans. Plasma Sci., Vol. 35, no. 2, Apr (2007) 4

Since the conventional antenna device is configured as described above, a large number of wiring structures are required when frequency selection plates are combined (particularly, in the case of Patent Document 2 and Non-Patent Document 1, a large number of electrodes are arranged). There is a problem that a large number of wiring structures are necessary), and the large number of wiring structures greatly affect the electrical characteristics of the frequency selection plate.
In addition, there is a problem that the combination with the frequency selection plate leads to an increase in scale and complexity of the apparatus.

  The present invention has been made to solve the above-described problems, and provides an array antenna apparatus that can have the function of a frequency selection plate with a small number of wiring structures without increasing the scale and complexity of the apparatus. For the purpose.

  An array antenna device according to the present invention accommodates a gas absorber that absorbs radio waves and a gas that generates plasma by ionization in a space that is disposed on the radio wave absorber and electrodes are disposed at both ends. A dielectric container, a dielectric substrate disposed on the dielectric container, and a plurality of radiating conductors disposed on the dielectric substrate and connected to a power feeding line; By adjusting the current supplied to the electrode, the state of the gas accommodated in the dielectric container is set to a plasma state where plasma is generated or a gas state where plasma is not generated.

  According to the present invention, a radio wave absorber that absorbs radio waves, and a dielectric that accommodates a gas that generates plasma by ionization in a space that is disposed on the radio wave absorber and electrodes are disposed at both ends. A body container, a dielectric substrate disposed on the dielectric container, and a plurality of radiation conductors disposed on the dielectric substrate and connected to a power feeding line, and the state control means is provided on the electrode. By adjusting the current to be supplied, the state of the gas accommodated in the dielectric container is set to a plasma state where plasma is generated or a gas state where plasma is not generated. There is an effect that the function of the frequency selection plate can be provided with a small wiring structure without causing complication.

It is a perspective view which shows the array antenna apparatus by Embodiment 1 of this invention. It is sectional drawing which shows the electric power feeding structure of the array antenna apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows operation | movement of an array antenna apparatus in case the state of gas 4 is a plasma state. It is explanatory drawing which shows operation | movement of an array antenna apparatus in case the state of gas 4 is a gas state. It is sectional drawing which shows a part (element antenna) of the array antenna apparatus of FIG. 1 utilized for the analysis of a radiation characteristic. It is explanatory drawing which shows the directivity pattern in the E surface (cut surface containing the ZX surface of FIG. 5) in case the thickness of a gas enclosure area | region is 2 mm. It is explanatory drawing which shows the directivity pattern in E surface (cut surface containing ZX surface of FIG. 5) in case the thickness of a gas enclosure area | region is 5 mm. It is explanatory drawing which shows the array antenna apparatus in the case of operate | moving as a frequency selection board, without generating plasma. It is explanatory drawing which shows the frequency characteristic of the transmittance | permeability between transmission / reception in case the thickness of a gas enclosure area | region is 2 mm. It is explanatory drawing which shows the frequency characteristic of the transmittance | permeability between transmission / reception in case the thickness of a gas enclosure area | region is 5 mm. It is sectional drawing which shows a part (element antenna) of the array antenna apparatus by Embodiment 2 of this invention. It is sectional drawing which shows a part (element antenna) of the array antenna apparatus by Embodiment 2 of this invention. It is sectional drawing which shows a part (element antenna) of the array antenna apparatus by Embodiment 3 of this invention. It is a block diagram which shows the array antenna apparatus by Embodiment 4 of this invention. It is a block diagram which shows the array antenna apparatus by Embodiment 5 of this invention.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing an array antenna apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view showing a feeding structure of the array antenna apparatus according to Embodiment 1 of the present invention.
1 and 2, the radio wave absorber 1 is made of, for example, carbon or ferrite, and is a member that absorbs radio waves incident on the array antenna device from the outside. In FIG. In FIG. 1, the upper surface of the radio wave absorber 1 is expressed as a plane for simplification of the drawing, but it is the same member. . The shape of the upper surface of the radio wave absorber 1 may be any shape as long as it can absorb incident radio waves.

The dielectric container 2 is disposed on the radio wave absorber 1 and accommodates a gas 4 that generates plasma by ionization in a space in which electrodes 3 are disposed at both ends.
In the example of FIGS. 1 and 2, the space containing the gas 4 is a recess provided on the upper surface of the dielectric container 2, and a dielectric substrate 5 described later is placed on the upper surface of the dielectric container 2. As a result, the gas 4 is sealed in the space of the dielectric container 2.
In the example of FIGS. 1 and 2, since the upper surface of the dielectric container 2 is square, the opening of the recess formed on the upper surface of the dielectric container 2 is also square.
The dielectric container 2 is assumed to be made of a dielectric material such as quartz, for example. However, the dielectric container 2 only needs to be able to seal the gas 4 in the space, and is made of a dielectric material other than quartz. It may be.

The electrode 3 is an elongate member disposed along the side wall surface of the concave portion of the dielectric container 2 constituting the space in which the gas 4 is accommodated. In the example of FIG. 1, the elongated electrode 3 extends in the Y direction, one electrode 3 is disposed along the right side wall surface of the recess, and the other electrode 3 is along the left side wall surface of the recess. Are arranged.
The gas accommodated in the space of the dielectric container 2 is preferably a gas containing a Group 18 element (rare gas element), but may be a medium such as nitrogen or oxygen, or a mixed medium thereof. . Further, other media such as Hg or fructogel (TMAE) may be added to adjust the degree of plasma generation.

The dielectric substrate 5 is disposed on the dielectric container 2 and seals the gas 4 accommodated in the space of the dielectric container 2.
The radiating conductors 6 are periodically arranged on the dielectric substrate 5 (in the example of FIG. 1, the 8 × 9 radiating conductors 6 are arranged in an array), and the radiating conductors 6 are provided for feeding. A coaxial inner conductor 7 is connected.
The coaxial inner conductor 7 has one end connected to the radiation conductor 6 and the other end connected to a communication device (not shown).
Further, the coaxial outer conductor 8 connected to the communication device extends to a position where it contacts the gas 4 accommodated in the space of the dielectric container 2.
A dielectric 9 is provided between the coaxial inner conductor 7 and the coaxial outer conductor 8.

  The current adjusting device 10 is connected to the electrode 3 by inserting an insertion pin or the like into a hole provided on the side surface of the dielectric container 2, and adjusts the current supplied to the electrode 3 from a built-in power source. Thus, the state of the gas 4 accommodated in the space of the dielectric container 2 is set to a plasma state where plasma is generated or a gas state where plasma is not generated. The current adjustment device 10 constitutes a state control unit.

Next, the operation will be described.
When a large current is supplied to the electrode 3 from the power supply of the current adjusting device 10 and the current is transmitted to the gas 4 accommodated in the space of the dielectric container 2, the gas 4 is ionized and the state of the gas 4 is changed. Transition from the gas state to the plasma state.
Hereinafter, the plasma conductivity σ at the time of transition to the plasma state will be described.

式（１）において、ω_ｐはプラズマ角周波数、ωはプラズマに入射された電磁波の角周波数、νは衝突周波数（自由電子が他の粒子と衝突して消滅する１秒当たりの平均回数）、ｊは虚数単位である。
［非特許文献２］
R.J. Vidmar、“On the use of Atmospheric Pressure Plasmas as Electromagnetic Reflections and Absorber、”IEEE Trans. Plasma Sci.、Vol.18、No.4、1990 The plasma generated from the gas 4 becomes non-magnetized, low temperature, and collisional plasma.
In the text of the complex relative permittivity epsilon _r tilde (specification in unmagnetized, the low-temperature-collision of the plasma, on the relationship between the electronic application, it is not possible to subject the symbol "~" on the character, epsilon _r Is expressed by the following formula (1), as disclosed in Non-Patent Document 2 below.

In equation (1), ω _p is the plasma angular frequency, ω is the angular frequency of the electromagnetic wave incident on the plasma, ν is the collision frequency (the average number of times per second that free electrons collide with other particles and disappear), j is an imaginary unit.
[Non-Patent Document 2]
RJ Vidmar, “On the use of Atmospheric Pressure Plasmas as Electromagnetic Reflections and Absorber,” IEEE Trans. Plasma Sci., Vol. 18, No. 4, 1990

また、複素比誘電率ε_ｒチルダは、一般的に、下記の式（３）のように表される。

式（３）において、ε_ｒはプラズマの比誘電率、σはプラズマの導電率である。 The plasma angular frequency ω _p can be expressed using an electron density n _e , an electron charge e, an electron mass m _e , and a vacuum relative dielectric constant ε ₀ as shown in the following formula (2).

Further, the complex relative dielectric constant ε _r tilde is generally expressed as the following formula (3).

In the formula (3), is epsilon _r dielectric constant of the plasma, sigma is the conductivity of the plasma.

Comparing equation (1) and equation (3), the relative dielectric constant ε _r of the plasma is obtained as in the following equation (4), and the electrical conductivity σ of the plasma is obtained as in the following equation (5). .

From equation (4), the relative dielectric constant epsilon _r of the plasma obtained from such angular frequency ω and the electron density n _e of the incident electromagnetic wave. Thus, the current regulator 10, by adjusting the value of the current supplied to the electrode 3, by adjusting the electron density n _e of the plasma generated from the gas 4, to control the relative permittivity epsilon _r of the plasma it can.
Further, from equation (5), the plasma conductivity sigma, obtained from such angular frequency ω and the electron density n _e of the incident electromagnetic wave. Thus, the current regulator 10, by adjusting the value of the current supplied to the electrode 3, by adjusting the electron density n _e of the plasma generated from the gas 4, it is possible to control the conductivity of the plasma sigma.
In the first embodiment, when the state of the gas 4 is set to a plasma state, the plasma conductivity σ is controlled to be a value that can be regarded as a conductor with respect to the angular frequency ω of the incident electromagnetic wave. And For example, the plasma conductivity σ is 4 to 10 S / m, preferably 10 S / m or more.
Thus, the state of the gas 4 can be changed from the gas state to the plasma state by controlling the plasma conductivity σ. Further, by controlling the relative dielectric constant ε _r of the plasma, the conductor loss of the plasma can be adjusted, and the reduction amount of the electromagnetic energy of the incident electromagnetic wave can be controlled to an appropriate amount.

Next, the difference between the operation of the array antenna apparatus when the gas 4 is in the plasma state and the operation of the array antenna apparatus when the gas 4 is in the gas state will be described.
FIG. 3 is an explanatory diagram showing the operation of the array antenna apparatus when the gas 4 is in the plasma state, and FIG. 4 is an explanatory diagram showing the operation of the array antenna apparatus when the gas 4 is in the gas state. is there.

The current adjusting device 10 adjusts the current supplied to the electrode 3 from the built-in power source, thereby setting the state of the gas 4 accommodated in the space of the dielectric container 2 to a plasma state where plasma is generated. .
At this time, the current adjusting device 10 adjusts the current supplied to the electrode 3 so that the electrical conductivity σ of the plasma generated from the gas 4 is a conductor with respect to the angular frequency ω of the radio wave (electromagnetic wave) to be radiated. Set to a value that can be considered.
As a result, the plasma behaves as a conductor. When a communication device (not shown) feeds the radiation conductor 6, the structure of FIG. 1 operates as an antenna, and thus radiates radio waves with a radiation pattern as shown in FIG. can do.
On the other hand, when the radio wave coming from outside is in the same frequency band as the operating frequency of the antenna, a scattered wave determined by the structure and a scattered wave of the antenna generated by exciting the power feeding structure of the antenna are generated. For this reason, there is a possibility that the radar cross-sectional area increases depending on the superposition of two scattered waves.

The current adjusting device 10 sets the state of the gas 4 accommodated in the space of the dielectric container 2 to a gas state in which plasma is not generated by preventing the current from being supplied from the built-in power source to the electrode 3.
In this case, since plasma having a conductive property is not generated, the structure of FIG. 1 does not operate as an antenna.
Here, the case where the state of the gas 4 is set to the gas state is shown, but even if the state of the gas 4 is set to the plasma state, the conductivity σ of the plasma generated from the gas 4 is the angular frequency of the radio wave. If ω is not controlled to a value that can be regarded as a conductor, the structure in FIG. 1 does not operate as an antenna.

When the state of the gas 4 is set to a gas state, the structure of FIG. 1 does not operate as an antenna, but since a plurality of radiation conductors 6 are arranged, it operates as a frequency selection plate for radio waves coming from the outside. To come.
Frequency selection plates are roughly classified into a bandpass type that transmits only radio waves in a specific frequency band and a band stop type that reflects only radio waves in a specific frequency band. In the case of FIG. Since the radiating conductors 6 are periodically arranged, it operates as a band-stop type frequency selection plate.
Therefore, if the frequency of the radio wave coming from the outside is the operating frequency as the frequency selection plate, the radio wave is reflected on the array antenna device of FIG.
On the other hand, if the frequency of the radio wave coming from the outside is not the operating frequency as the frequency selection plate, as shown in FIG. 4, the radio wave is incident on the array antenna apparatus of FIG. However, since the array antenna apparatus of FIG. 1 includes the radio wave absorber 1, the incident radio wave is absorbed by the radio wave absorber 1, and reflection hardly occurs. Therefore, the radar cross-sectional area can be reduced.

Next, the evaluation results of the radiation characteristics as the antenna and the transmission characteristics as the frequency selection plate in the array antenna apparatus of FIG. 1 will be described.
FIG. 5 is a cross-sectional view showing a part (element antenna) of the array antenna apparatus of FIG. 1 used for analysis of radiation characteristics.
In FIG. 5, the thickness of the space of the dielectric container 2 in which the gas 4 is accommodated (the thickness of the gas sealing region) is two types, 2 mm and 5 mm.
Further, the conductivity σ of plasma generated from the gas 4 is set to three types of 100 S / m, 250 S / m, and 500 S / m.
In the analysis of this radiation characteristic, the array element directivity pattern in the infinite periodic array antenna is obtained. The material of the discharge tube is quartz (relative dielectric constant = 3.78), and the analysis frequency is 0.85 GHz which is the operating frequency of the antenna.

FIG. 6 is an explanatory diagram showing a directivity pattern on the E surface (a cut surface including the ZX surface in FIG. 5) when the thickness of the gas sealing region is 2 mm.
FIG. 6 also shows a directivity pattern when copper is used instead of plasma as a comparison target.
When the thickness of the gas sealing region is 2 mm, the higher the conductivity σ of the plasma generated from the gas 4 is, the closer the directivity pattern is to the directivity pattern when copper is used, and the plasma conductivity. The directivity pattern when the rate σ is 500 S / m substantially matches the directivity pattern when copper is used.
Therefore, when the thickness of the gas-filled region is 2 mm, if the plasma conductivity σ is set to 500 S / m, the antenna can be operated as an antenna having the same radiation characteristics as when copper is used.

FIG. 7 is an explanatory diagram showing a directivity pattern on the E plane (cut plane including the ZX plane in FIG. 5) when the thickness of the gas sealing region is 5 mm.
FIG. 7 also shows a directivity pattern when copper is used instead of plasma as a comparison target.
When the thickness of the gas-filled region is 5 mm, the thickness of the gas-filled region is thicker than when the gas-filled region is 2 mm. I can't get out. For this reason, even if the electrical conductivity σ of the plasma generated from the gas 4 is lowered as compared with the case where the thickness of the gas filled region is 2 mm, the directivity pattern is the same as the directivity pattern when copper is used. It ’s close.
Therefore, when the thickness of the gas-filled region is 5 mm, even if the conductivity σ of the plasma generated from the gas 4 is lowered, it can be operated as an antenna having the same radiation characteristics as when copper is used.

FIG. 8 is an explanatory diagram showing an array antenna apparatus when operating as a frequency selection plate without generating plasma.
In FIG. 8, the thickness of the space of the dielectric container 2 in which the gas 4 is accommodated (the thickness of the gas sealing region) is two types, 2 mm and 5 mm.
In the analysis of the transmission characteristics, the coaxial structure is omitted for simplicity, and the radio wave transmission source and reception source are omnidirectional.
Further, when used as a frequency selection plate, the gas 4 is not in a plasma state, and only being filled with the gas 4 hardly affects the electrical characteristics, and thus is analyzed as a vacuum.

FIG. 9 is an explanatory diagram showing the frequency characteristics of the transmittance between transmission and reception when the thickness of the gas sealing region is 2 mm.
FIG. 10 is an explanatory diagram showing the frequency characteristics of the transmittance between transmission and reception when the thickness of the gas filled region is 5 mm.
In the frequency characteristics shown in FIGS. 9 and 10, the frequency 1.5 GHz is the operating frequency of the frequency selection plate, and a radio wave (plane wave) having a frequency of 1.5 GHz cannot pass through the frequency selection plate.
On the other hand, at frequencies other than 1.5 GHz, it can be seen that light is transmitted at a level of approximately −5 dB or more. However, the transmitted radio wave is absorbed by the radio wave absorber 1.
Therefore, even when the thickness of the gas sealing region is 2 mm or when the thickness of the gas sealing region is 5 mm, it can be operated as a frequency selection plate that reflects only radio waves in a specific frequency band.

As is apparent from the above, according to the first embodiment, the ion absorber 1 is disposed in the space where the radio wave absorber 1 that absorbs radio waves is disposed, and the electrode 3 is disposed at both ends. Thus, the dielectric container 2 containing the gas 4 that generates plasma, the dielectric substrate 5 disposed on the dielectric container 2, the dielectric substrate 5 disposed on the dielectric substrate 5, A plurality of radiation conductors 6 connected to coaxial inner conductors 7 as lines are provided, and the current 4 is accommodated in the dielectric container 2 by the current adjusting device 10 adjusting the current supplied to the electrodes 3. Is set to a plasma state in which plasma is generated or a gas state in which plasma is not generated, so that the function of the frequency selection plate is provided with a small wiring structure without causing an increase in the scale and complexity of the apparatus. There is an effect that can be.
That is, since the structure of FIG. 1 shares the array antenna and the frequency selection plate, it is possible to suppress an increase in scale and complexity of the apparatus. In addition, it is not necessary to arrange a large number of electrodes as in the conventional example, and it is only necessary to arrange a pair of electrodes 3, so that a large number of wiring structures greatly affect the electrical characteristics of the frequency selection plate. Absent.

Embodiment 2. FIG.
In the first embodiment, the figure shows that the dielectric substrate 5 is placed on the dielectric container 2 having a space whose upper side is open, thereby sealing the gas 4 in the space. The dielectric container 2 may have a hollow space, and the gas 4 may be accommodated in the space.
11 and 12 are sectional views showing a part (element antenna) of an array antenna apparatus according to Embodiment 2 of the present invention.
In particular, FIG. 11 shows an element antenna arranged at the end of the array antenna device, and FIG. 12 shows an element antenna arranged at the end other than the end of the array antenna device.
11 and 12, the same reference numerals as those in FIGS. 1 and 2 indicate the same or corresponding parts, and thus the description thereof is omitted.

In the first embodiment, the gas 4 in the space is sealed by placing the dielectric substrate 5 on the dielectric container 2, but the gas 4 leaks while maintaining the sealed state of the gas 4. In order to prevent this, the type of dielectric substrate 5 is limited.
On the other hand, in the second embodiment, as shown in FIGS. 11 and 12, the dielectric container 2 includes a hollow space, and the gas 4 is accommodated in the space. Regardless of the type of the dielectric substrate 5, the sealed state of the gas 4 can be maintained.

In the case where the dielectric container 2 has a structure having a hollow space, when the plasma is generated from the gas 4, the upper surface of the dielectric container 2 and the multilayer substrate composed of the dielectric substrate 5 become the element antenna.
For example, when the relative dielectric constant of the dielectric container 2 is ε _r1 , the thickness of the dielectric container 2 is t ₁ , the relative dielectric constant of the dielectric substrate 5 is ε _r2 , and the thickness t ₂ of the dielectric substrate 5 is effective. The relative dielectric constant ε _eff is expressed as the following formula (6).

  As apparent from the above, according to the second embodiment, the dielectric container 2 has a hollow space, and the gas 4 is accommodated in the space. When selecting the material, there is an effect that the material can be selected regardless of the gas 4 sealing structure.

Embodiment 3 FIG.
In the first and second embodiments, the radiation conductor 6 is disposed on the dielectric substrate 5. However, a plurality of radiation conductors 6 and other radiation conductors are disposed inside the dielectric container 2. You may be allowed to.
13 is a sectional view showing a part (element antenna) of an array antenna apparatus according to Embodiment 3 of the present invention. In FIG. 13, the element antenna arrange | positioned other than the edge part of an array antenna apparatus is shown. In FIG. 13, the same reference numerals as those in FIGS.
The radiation conductor 11 is disposed separately from the radiation conductor 6 inside the dielectric container 2.

In the example of FIG. 13, the radiating conductor 11 having a shape different from that of the radiating conductor 6 is arranged above the space for storing the gas 4 in the dielectric container 2. A radiation conductor 11 having a shape different from that of the radiation conductor 6 may be arranged in the lower part, and the radiation conductor 11 may be arranged in both the upper part and the lower part of the space for storing the gas 4. Also good.
Further, the radiating conductor 11 may be inserted not in the upper part or the lower part of the space of the dielectric container 2 but in the dielectric constituting the dielectric container 2.

  When the state of the gas 4 is set to the plasma state, the radiating conductor 11 has little influence, but when the state of the gas 4 is set to the gas state, the radiating conductor 6 and the radiating conductor 11 are used to form a multilayer. Therefore, the transmission characteristics of the frequency selection plate can be adjusted according to the arrangement and shape of the radiation conductor 11.

Embodiment 4 FIG.
FIG. 14 is a block diagram showing an array antenna apparatus according to Embodiment 4 of the present invention. In FIG. 14, the same reference numerals as those in FIGS.
The gas exhaust hole 21 is a hole provided so that the density of the gas 4 accommodated in the space of the dielectric container 2 can be adjusted, and a hose 22 is connected to the gas exhaust hole 21.
The gas density adjusting device 23 is connected to a gas cylinder 25 through a hose 24, and the gas 4 stored in the gas cylinder 25 is enclosed in the space of the dielectric container 2 or accommodated in the space of the dielectric container 2. It is a device that adjusts the density of the gas 4 accommodated in the space of the dielectric container 2 by exhausting the gas 4 that is present.
The hoses 22 and 24, the gas density adjusting device 23, and the gas cylinder 25 constitute gas density adjusting means.

式（７）において、ｎ_ｎは粒子の密度、ρは粒子が弾性衝突する場合の等価断面積、ｓは粒子の速度である。なお、ρｓバー（明細書の文章中では、電子出願の関係上、文字の上に“−”の記号を付することができないので、ρｓバーのように表記している）は、等価断面積ρと速度ｓの積の平均値を表している。
［非特許文献３］
Francis F. Chen著、内田岱二郎訳『プラズマ物理入門』、丸善、1977年 The complex relative permittivity ε _r tilde in the non-magnetized / low temperature / impact plasma changes according to the collision frequency ν as shown in the above equation (1).
The collision frequency ν is the average number of times per second at which free electrons collide with other particles and disappear, and the movement of the electrons is determined by the voltage applied by the power supply of the current adjusting device 10.
From the description of Non-Patent Document 3 below, the collision frequency ν is defined by the following equation (7).

In the formula (7), the n _n the density of the particles, [rho equivalent cross-sectional area when the particles are elastic collision, s is the velocity of the particle. Note that the ρs bar (in the text of the specification, the symbol “−” cannot be added on the letter because of the electronic application, so it is represented as a ρs bar) is the equivalent cross-sectional area. It represents the average value of the product of ρ and speed s.
[Non-Patent Document 3]
Francis F. Chen, translated by Junjiro Uchida, “Introduction to Plasma Physics”, Maruzen, 1977

From equation (7), it can be seen that the collision frequency ν increases as the particle size of the gas increases or the density of the gas increases.
Therefore, the gas density adjusting device 23 adjusts the density of the gas 4 accommodated in the space of the dielectric container 2 or a gas different from the gas 4 currently accommodated in the space of the dielectric container 2 from the gas cylinder 25. Can be adjusted by adjusting the collision frequency ν.
In this way, by adjusting the collision frequency ν, the plasma dielectric constant ε _r and conductivity σ can be controlled in a wider range, so the antenna radiation characteristics and the frequency selection plate transmission characteristics can be adjusted. can do.

Embodiment 5. FIG.
FIG. 15 is a block diagram showing an array antenna apparatus according to Embodiment 5 of the present invention. In FIG. 15, the same reference numerals as those in FIG.
The frequency detection device 31 is a device that detects the frequency of an incident radio wave. The frequency detection device 31 constitutes frequency detection means.
Since the process of detecting the frequency of the radio wave by the frequency detection device 31 is a known technique, detailed description thereof is omitted.
The control device 32 controls the current adjusting device 10 according to the frequency detected by the frequency detecting device 31, thereby adjusting the current supplied to the electrode 3 and adjusting the gas density according to the frequency detected by the frequency detecting device 31. By controlling the device 23, the device adjusts the density of the gas 4 accommodated in the space of the dielectric container 2. The control device 32 constitutes a state control means and a gas density adjustment means.

Next, the operation will be described.
However, since the components other than the frequency detection device 31 and the control device 32 are the same as those in the first to fourth embodiments, only the processing contents of the frequency detection device 31 and the control device 32 will be described here.
When a radio wave is incident from the outside, the frequency detection device 31 detects the frequency of the radio wave and notifies the control device 32 of the frequency.

The control device 32 includes, for example, a table indicating the relationship between the frequency of the incident radio wave and the current supplied to the electrode 3 and the relationship between the frequency of the incident radio wave and the density of the gas 4.
For example, if the density of the gas 4 necessary for reflecting the frequency of the incident radio wave has been analyzed in advance, the control device 32 is provided with a table indicating the density of the gas 4 corresponding to the frequency of the radio wave.
For example, when it is necessary to radiate a radio wave having the same frequency as the frequency of the radio wave incident from the outside, a current supplied to the electrode 3 necessary for radiating a radio wave having the same frequency as the frequency of the incident radio wave is supplied. If analyzed in advance, the control device 32 is provided with a table indicating the current corresponding to the frequency of the incident radio wave.

When receiving the notification of the frequency of the incident radio wave from the frequency detector 31, the control device 32 refers to the table to grasp the current corresponding to the frequency of the incident radio wave and supplies the current to the electrode 3. The current adjusting device 10 is controlled as described above.
Further, the density of the gas 4 corresponding to the frequency of the incident radio wave is grasped by referring to the table, and the density of the gas 4 accommodated in the space of the dielectric container 2 is the density of the grasped gas 4. The gas density adjusting device 23 is controlled so as to match.
Here, an example is shown in which the control device 32 controls the current adjustment device 10 and the gas density adjustment device 23 with reference to the table, but the present invention is not limited to this, and the current adjustment is performed from the frequency of the incident radio wave. Control amounts for the device 10 and the gas density adjusting device 23 may be calculated to control the current adjusting device 10 and the gas density adjusting device 23.

For example, if the frequency of the incident radio wave is increased, the density of the gas 4 is controlled to be increased. If the frequency of the incident radio wave is decreased, the density of the gas 4 is controlled to be decreased. Even when the frequency of the received radio wave changes in real time, a frequency selection plate capable of reflecting the radio wave can be obtained.
Further, the current to the electrode 3 is controlled so that the plasma conductivity σ increases as the frequency of the incident radio wave increases, and the plasma conductivity σ decreases as the frequency of the incident radio wave decreases. As described above, if the current to the electrode 3 is controlled, an antenna capable of emitting a radio wave having the same frequency as the incident radio wave can be obtained even when the frequency of the incident radio wave changes in real time.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  DESCRIPTION OF SYMBOLS 1 Radio wave absorber, 2 Dielectric container, 3 Electrode, 4 Gas, 5 Dielectric board | substrate, 6 Radiation conductor, 7 Coaxial inner conductor (Power feed line), 8 Coaxial outer conductor, 9 Dielectric, 10 Current adjustment device ( State control means), 11 radiation conductor, 21 gas exhaust hole, 22, 24 hose (gas density adjusting means), 23 gas density adjusting device (gas density adjusting means), 25 gas cylinder (gas density adjusting means), 31 frequency detector (Frequency detection means), 32 control device (state control means, gas density adjustment means).

Claims (6)

A radio wave absorber that absorbs radio waves;
A dielectric container containing a gas that generates plasma by ionization, in a space that is disposed on the radio wave absorber and electrodes are disposed at both ends;
A dielectric substrate disposed on the dielectric container;
A plurality of radiation conductors disposed on the dielectric substrate and connected to a power feed line; and
State control means for adjusting the current supplied to the electrode to set the state of the gas accommodated in the dielectric container to a plasma state in which plasma is generated or a gas state in which plasma is not generated. Antenna device.   2. The array antenna device according to claim 1, wherein the dielectric container has a hollow space, and gas is accommodated in the space.   The array antenna apparatus according to claim 1 or 2, wherein a plurality of radiation conductors different from the radiation conductor are arranged inside the dielectric container.   The array antenna apparatus according to any one of claims 1 to 3, further comprising a gas density adjusting unit that adjusts a density of a gas stored in the dielectric container. Provided with frequency detection means for detecting the frequency of incident radio waves,
5. The array antenna apparatus according to claim 4, wherein the gas density adjusting means adjusts the density of the gas stored in the dielectric container in accordance with the frequency detected by the frequency detecting means. Provided with frequency detection means for detecting the frequency of incident radio waves,
5. The array antenna apparatus according to claim 1, wherein the state control unit adjusts a current supplied to the electrode in accordance with a frequency detected by the frequency detection unit. .

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