JP2007116573A - Array antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a small-sized array antenna, of which the scanning range of beam directivity is wide, which can be used even in a high frequency band of 1GHz or higher without changing a frequency. <P>SOLUTION: When both switches SW1, SW2 are simultaneously turned to (b) side as illustrated, a conductor forming an odd-numbered unit pattern U from a power feeding point side is set to a low potential, and a conductor forming an even-numbered unit pattern U from the power feeding point side is set to a high potential. Therefore, potentials different from each other are given to conductors forming unit patterns U adjacent to each other in an x-axis direction. Accordingly, an electric field in the x-axis direction is formed in a gap G1 between the conductors of the unit patterns U adjacent to each other. Thus, when both the switches SW1, SW2 are simultaneously turned to the (b) side as illustrated, moment vectors of electric dipoles in liquid crystal molecules of liquid crystal 13 are oriented in the x-axis direction, respectively. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an array antenna (leakage wave antenna) having a strip line formed by periodically and repeatedly arranging a predetermined unit pattern made of a conductor on the front side of a dielectric substrate having a ground plate on the back surface. In particular, the present invention relates to an antenna having controllable directivity.
The present invention is useful for radars and communication devices that transmit or receive electromagnetic waves in the millimeter wave band or microwave band, and is very useful for reducing the size of antennas or the space required for installation.

  FIG. 9 illustrates a configuration example of a conventional strip array antenna (leakage wave antenna) having a CRLH (Composite Right and Left Handed) transmission line on a dielectric substrate. The CRLH line includes a gap that periodically divides the transmission line (the main line in the x-axis direction), a stub branched from the transmission line, and the like. In this antenna, the direction of the group velocity and the phase velocity of transmitted electromagnetic waves can be opposite to each other in a certain frequency band by the action of the capacitance provided by the gap and the inductance provided by the stub. Thus, by changing the frequency of the transmitted electromagnetic wave, the angle region θ <0 inclined from the z-axis direction to the −x-axis direction in the figure opposite to the direction in which the electromagnetic wave propagates on the main line. Even electromagnetic waves can be emitted. As a result, when the direction of the radiation beam is changed, there is an advantage that the scanning range of the radiation beam can be widened. In this way, the principle that the direction of the phase velocity and the group velocity are opposite is disclosed in detail in, for example, Non-Patent Document 1 below. However, unless the frequency is changed greatly, it is difficult to provide directivity in a direction inclined in the −x axis direction.

  Non-Patent Document 2 below discloses a control method for variably controlling the radiation angle of a radiation beam based on predetermined electronic control while fixing the frequency of an electromagnetic wave input from a feeding point to a constant value. . In this radiation angle control method, for example, the varactor diodes are arranged close to the individual gaps and stubs of the wiring pattern of FIG. Is variably controlled.

  Patent Document 1 below discloses a beam scanning antenna using a reflector having an EBG structure (Electrical Band Gap structure) in which a metal patch 1 having a via in the center is periodically arranged on a dielectric substrate (FIG. 10-). A, -B) has been proposed. This beam scanning antenna changes the capacitance between the metal patches (1, 2) of the reflector to change the traveling direction of the reflected wave of the electromagnetic wave incident on the reflector from a predetermined direction, that is, the reflected wave The directivity is variably controlled. The capacitance between the metal patches (1, 2) generates an electric field between the metal patch 1 and the metal patch 2 by a DC voltage applied between the via 1 and the via 2, and the metal patch is generated by the electric field. It is variably controlled by changing the relative dielectric constant of the liquid crystal disposed therebetween.

  In addition, as another control method, for example, the dielectric constant of the material through which the electromagnetic wave propagates is variably controlled by electrically controlling the permeability of the material using ferrite or the like. There is a method for variably controlling the above. That is, as such a control method, for example, the dielectric constant of the dielectric substrate constituting the target antenna is variably controlled by voltage, and thereby the radiation angle of the radiation beam of the array antenna is variably controlled to a desired angle. A control method can be considered. Examples of such a dielectric substrate material whose dielectric constant is variably controlled include liquid crystal and ferroelectric.

In the field of electromagnetic wave sensing or wireless communication, it is desirable that the directivity of the radiation beam of the antenna is controlled without changing the frequency of the radiated electromagnetic wave.
Tatsuo Ito and two others, 'CHARACTERISTICS AND APPLICATIONS OF PLANAR NEGATIVE REFRACTIVE INDEX MEDIA', MWE2003, WS02-03 Tatsuo Ito and two others, 'Electronically-Controlled Metamaterial-Based Transmission Line as a Continuous-Scanning Leaky-Wave Antenna', 2004 IEEE MTT-S Digest TU1D-4. US Patent: US 6,552,696 B1

  However, the conventional array antenna described in Non-Patent Document 1 cannot variably control the radiation angle of the radiation beam of the antenna while keeping the frequency of the electromagnetic wave input from the feeding point constant. For this reason, an antenna that employs this method is not suitable for an antenna that radiates or receives an electromagnetic wave having a certain frequency, such as a millimeter wave radar.

In the conventional array antenna described in Non-Patent Document 2, a varactor diode is used as a variable capacitor. However, since a varactor diode generally has a large transmission loss, a varactor is used in a frequency band of several GHz or more. It is difficult to operate the diode as a desired variable capacitor. For this reason, this prior art cannot be used for an array antenna that handles electromagnetic waves in a frequency band of several GHz or more.
Further, even in a frequency band of 1 GHz or less in which the radiation angle can be variably controlled, it is not always easy to ensure a sufficiently large capacity displacement ratio (change rate) with respect to a standard capacity (predetermined reference capacity) in a varactor diode. Therefore, it is not always easy to ensure a large variation range of the radiation angle.

  Further, the conventional beam scanning antenna described in Patent Document 1 (FIGS. 10A and 10B) changes the dielectric constant of the liquid crystal portion by changing the direction of the liquid crystal molecules, thereby directing the reflected beam. However, these conventional beam scanning antennas have problems such as the following (1) to (4) related to productivity, controllability, thinning and downsizing. is there.

(1) In a device that handles millimeter waves or microwaves, the thickness of a liquid crystal portion used for variably controlling capacitance or inductance is normally required to be about 100 μm. However, if such a thickness is provided, for example, when a voltage is applied between the metal patch 1 and the metal patch 2, the direction of the liquid crystal molecules is changed to a desired direction in several milliseconds. However, when the application of the voltage is interrupted, it takes several seconds for the orientation of each liquid crystal molecule to return to the original orientation. This is because the liquid crystal molecules return to their original orientation due to the thermal motion of the liquid crystal molecules, and the restoration time relating to the orientation of the liquid crystal molecules required at this time is proportional to the square of the thickness of the liquid crystal portion. Therefore, as long as such a conventional method is adopted, it is difficult to variably control the beam directivity at high speed. That is, such a conventional method cannot be adopted for a system that needs to scan a beam at high speed.

(2) As shown in FIGS. 10A and 10B, since the beam scanning antenna is configured using a reflector having an EBG structure, a power feeding antenna for irradiating the reflector with electromagnetic waves is separately prepared. There is a need.
(3) Since only the phase of the reflected wave reflected by the reflecting plate is changed, the angle at which the reflection intensity reaches a peak can be controlled, but the amount of reflection from each patch cannot be changed. The beam pattern cannot be variably controlled.
(4) The voltage for changing the dielectric constant of the liquid crystal is applied to the via portion floating from the ground plate, but the structure of this portion must be complicated.

  Further, as described above, for example, a material such as a ferroelectric material or ferrite is considered as another material suitable for a control method for variably controlling the dielectric constant and permeability of the dielectric substrate constituting the target antenna. However, when these materials are used for a dielectric substrate or the like, the power loss of electromagnetic waves propagating in the antenna becomes very large, so it is difficult to secure a large antenna gain. .

  The present invention has been made to solve the above-described problems, and its purpose is to provide a beam directivity scanning range that can be used in a high frequency band of 1 GHz or higher without changing the frequency. This is to realize a wide and small array antenna.

In order to solve the above problems, the following means are effective.
That is, the first means of the present invention comprises a dielectric substrate, a strip line formed by arranging a plurality of identical or similar unit patterns made of conductors in a predetermined direction on the front side of the dielectric substrate, and a dielectric In an array antenna having a ground plate made of a conductor formed on the back surface of a substrate, a dielectric constant variable member whose dielectric constant changes according to an applied electric field, and an electric field is applied to the dielectric constant variable member from a plurality of directions An electric field setting means is provided, and the unit pattern is provided with a transmission line that runs in a predetermined direction, a gap that divides the transmission line in the middle, and a stub that branches off from the transmission line. The conductors that are arranged close to the gaps or stubs and form unit patterns adjacent to each other in the predetermined direction are different from each other by the electric field setting means. That is to give the potential.

Hereinafter, the predetermined direction in which a plurality of unit patterns are arranged on the front side of the dielectric substrate is defined as an x-axis direction. The direction perpendicular to the dielectric substrate is taken as the z-axis direction.
The gap is formed between the conductors forming the unit patterns adjacent to each other in the x-axis direction, and these gaps are also included in the unit pattern.

According to a second means of the present invention, in the first means, the dielectric constant variable member is made of a liquid crystal, a ferroelectric material, or a ferromagnetic material.
According to a third means of the present invention, in the first or second means, the dielectric constant variable member is disposed between the unit pattern and the ground plate.

According to a fourth means of the present invention, in any one of the first to third means, a dielectric constant variable member is disposed on the surface of the dielectric substrate.
By the above means of the present invention, the above-mentioned problem can be effectively or rationally solved.

The effects obtained by the above-described means of the present invention are as follows.
That is, according to the first means of the present invention, since the electric field can be applied to the variable dielectric constant member from a plurality of directions using the electric field setting means, the direction of the electric field applied to the variable dielectric constant member Can be changed to a desired direction at any time at high speed. Therefore, according to the first means of the present invention, the dielectric constant of the dielectric constant variable member can be variably controlled according to the direction of the electric field, thereby changing the capacitance provided by the gap and the inductance provided by the stub. Can be made. For this reason, it is possible to control the phase and power of the high-frequency wave passing through the strip line and the phase and radiation amount of the radiated electromagnetic wave, so that the radiation direction of the array antenna beam can be changed, the beam width of the array antenna The pattern can be changed.

  Further, when it is desired to apply an electric field in the z-axis direction to the dielectric constant variable member, it is only necessary to apply different potentials to the conductors constituting the unit pattern and the ground plate, and in the x-axis direction perpendicular thereto. In order to form an electric field, different potentials may be applied to conductors forming unit patterns adjacent to each other in the x-axis direction. Therefore, according to the first means of the present invention, in constructing the electric field setting means for applying an electric field from a plurality of directions to the dielectric constant variable member, the other for applying an electric field to the dielectric constant variable member. The dedicated electrode is not necessarily required. Further, the conductor and the ground plate constituting the unit pattern can be formed in a plane parallel to the front surface or the back surface of the dielectric substrate. Therefore, according to the first means of the present invention, the electric field setting means can be easily formed with a simple configuration.

  Further, according to the second means of the present invention, since the dielectric constant of the dielectric constant variable member can be significantly changed, a large degree of freedom related to various controllability such as a beam scanning range can be secured. it can.

  According to the third means of the present invention, since the variable dielectric constant member does not protrude above the unit pattern, the array antenna can be effectively thinned or miniaturized.

  In addition, according to the fourth means of the present invention, since the variable dielectric constant member is arranged above the unit pattern, the arrangement of the variable dielectric constant member becomes easy.

In particular, when the dielectric constant variable member is made of liquid crystal, the distance between a pair of electrodes for applying an electric field to the liquid crystal is preferably 0.2 mm or less. Alternatively, when the dielectric constant variable member is made of liquid crystal, it is desirable that the length be 0.2 mm or less in at least two directions in which an electric field is formed.
When the dielectric constant variable member is made of liquid crystal, the liquid crystal molecules can be changed to a desired direction in a few milliseconds even with a voltage of 100 V or less.

  The dielectric substrate is preferably made of a material having a small relative dielectric constant, such as tetrafluoroethylene resin. In addition to the liquid crystal, for example, a ferroelectric substance can be used as the dielectric constant variable member. As a more desirable material, for example, nematic liquid crystal is useful.

  In addition, the frequency of the electromagnetic wave radiated or received by the array antenna of each example illustrated below is assumed to be a frequency arbitrarily fixed in the range of about 1 GHz to 100 GHz, and the unit pattern is set in the x-axis direction. Of course, the pattern formation period in the repeated formation may be determined according to the frequency in the same manner as in the prior art. However, the operations and effects that can be obtained by the present invention are not necessarily limited only to the array antenna that handles electromagnetic waves in the above frequency band. Further, the present invention does not disturb the conventional operation and effect obtained by changing the operating frequency of the antenna.

The array antennas of the embodiments illustrated below are designed assuming a scanning frequency of about several times per second over the entire scanning range (all scanning angles θ). Of course, the frequency can be arbitrarily set as required.
In addition, it is desirable that the unit patterns as the constituent elements of the strip line are periodically arranged using the same pattern, but it is not always necessary to use only the same pattern, and it is not always necessary to periodically There is no need to arrange them. Therefore, for example, the above unit pattern that is a constituent element of the strip line may not have the same dimensions such as the thickness and length of each part such as the transmission line and the stub, and even if the gaps and the like are not uniform. good.

Hereinafter, the present invention will be described based on specific examples.
However, the embodiments of the present invention are not limited to the following examples.

  FIG. 1 is a perspective view of the strip line 14 of the array antenna 100 according to the first embodiment designed so that the high frequency input from the feeding point P is 77 GHz. The strip line 14 of the array antenna 100 is periodically structured by the unit pattern U, and the unit pattern U constituting the periodic wiring pattern is divided into 16 periods so that the main line 11 is in the x-axis direction. It is composed by repeating. The array antenna 100 includes a conductor (wiring pattern) in which the strip line 14 is formed on a dielectric substrate 15 made of tetrafluoroethylene resin having a relative dielectric constant of 2.2 and having a thickness of about 0.13 mm. It is formed using. Each unit pattern U constituting the strip line 14 has a main line 11 (transmission line) and a stub 12 and is fed from a feeding point P at the left end in the figure. Each unit pattern U has a gap G1 on the left and right.

  FIG. 2-A shows a partial plan view of the array antenna 100. The gap G1 is formed between the conductors forming the unit patterns U adjacent to each other in the x-axis direction, and is formed of nematic liquid crystal below the conductor as shown in FIG. A liquid crystal 13 is provided. The space region occupied by the liquid crystal 13 at one location is 0.3 mm in the x-axis direction and 0.3 mm in the y-axis direction, and the thickness (the length in the z-axis direction) is the same as that of the dielectric substrate 15 described above. It is. The liquid crystal 13 is for variably controlling the capacitance of the gap G1, and in order to increase the capacitance, the opposing portions 11a and 11b of the main line 11 constituting the gap G1 are arranged in the y-axis direction. The liquid crystal 13 is widened and disposed below the facing portions 11a and 11b.

  FIG. 2-B shows a circuit diagram of the electric field setting means of the array antenna 100. With the wiring 2, the ground plate 16 can be connected to the anode of the battery E via the switch SW <b> 1. Further, the conductor forming the odd-numbered unit pattern U from the feeding point side is directly connected to the cathode of the battery E by the wiring 1. Moreover, the conductor of the even-numbered unit pattern U from the feeding point side can be connected to the anode and the cathode of the battery E through the switch SW2 by the wiring 1 ′. In addition, the low-pass filter LPF indicated by a circle in the figure is inserted in each part in order to prevent high-frequency transmission.

With this configuration of the electric field setting means, when both the switches SW1 and SW2 are simultaneously tilted to the a side as shown in the figure, the ground plate 16 becomes a high potential due to the potential applied by the battery E, and the strip line 14 (all unit patterns) U) is at a low potential.
Therefore, when both switches SW1 and SW2 are simultaneously tilted to the a side, the electric dipole moment vectors of the liquid crystal molecules of the liquid crystal 13 are respectively aligned in the z-axis direction. However, when the potential difference between the strip line 14 and the ground plate 16 is small, it goes without saying that the orientation effect is somewhat relieved.

When the switches SW1 and SW2 are simultaneously tilted to the b side as shown in the figure, the conductor forming the odd-numbered unit pattern U from the feeding point side is set to a low potential, and the even-numbered unit from the feeding point side. The conductor forming the pattern U is set to a high potential. For this reason, different potentials are applied to the conductors forming the unit patterns U adjacent to each other in the x-axis direction. Therefore, an electric field in the x-axis direction is formed in the gap G1 between the conductors of the unit patterns U adjacent to each other. Therefore, when both switches SW1 and SW2 are simultaneously tilted toward the b side, the electric dipole moment vectors of the liquid crystal molecules of the liquid crystal 13 are each oriented in the x-axis direction. However, in this case as well, when the DC voltage provided by the battery E is small, the alignment action is also reduced.
As a result, for example, when an electric field in the x-axis direction is applied to the liquid crystal 13, if the DC voltage of the battery E is 100v, the connection state of the switches SW1 and SW2 is changed from b to a. As a result, the relative dielectric constant of the liquid crystal 13 increases from 2.5 to 2.7.

FIG. 3 is a graph illustrating the radiation characteristic (simulation result) of the array antenna 100. This simulation is a verification of the array antenna 100 described above based on the known transmission line theory. The radiation angle θ in FIG. 3 is defined as an angle on the zx plane as shown in FIG. 1, and the positive direction of the z-axis is θ = 0 °.
The simulation conditions for the cases (i) to (iii) shown in the figure are as follows.
(Simulation conditions)
(I) Power supply voltage = 0v, both switches SW1 and SW2 are in the state a
(Ii) Power supply voltage = 50v, both switches SW1 and SW2 are in the state a
(Iii) Power supply voltage = 100v, both switches SW1 and SW2 are in the state a

From the simulation results of FIG. 3 verified based on these conditions, the beam radiation angle θ of the array antenna 100 is obtained by the above-described variable control of the power supply voltage using the variable resistor R _v of FIG. It was found that the desired angle can be controlled in the range of about −22 ° to + 13 °.
Further, as shown in the condition (iii) of FIG. 3, immediately after the radiation angle θ reaches the maximum value, the liquid crystal molecules constituting the liquid crystal 13 are determined by another experiment in which both the switches SW1 and SW2 are changed to the state b. It was found that the direction of can be returned to the original x-axis direction at high speed. The time required for this restoration is as short as about 10 msec because an electric field in the x-axis direction is used.
Therefore, by using the array antenna 100 of the first embodiment, the radiation angle of the antenna beam can be electrically controlled over a wide range of about 35 °, and at the same time, a very high-speed scanning operation can be realized. Become.

FIG. 4 is a plan view of the array antenna 100 ′ according to the second embodiment. In this array antenna 100 ', a rectangular pool region 15a is formed in the center of a dielectric substrate 15 made of tetrafluoroethylene resin, and a liquid crystal 13 made of nematic liquid crystal (variable dielectric constant) is formed in the pool region 15a. Member) is filled.
FIG. 5 is a cross-sectional view of the array antenna 100 ′ taken along the line AA ′. In the array antenna 100 ′ of the second embodiment, the full width in the y-axis direction of the pool region 15 a that fills the liquid crystal 13 is wider than the full width in the y-axis direction of the strip line 14. A ground plate 16 made of a conductor is formed on the back surface of the dielectric substrate 15.

For example, in this way, the liquid crystal 13 (variable dielectric constant member) may be widely arranged on the lower surface of the strip line 14. Further, substantially the entire dielectric substrate may be composed of liquid crystal.
The arrangement of these liquid crystals has advantages and disadvantages. In order to reduce the power loss due to the liquid crystals as much as possible, it is better to arrange the liquid crystals only in the region below the gap G1, while scanning the beam at a wider angle. In order to do this, it is better to arrange the liquid crystal wider than the region below the gap G1.

6A and 6B are cross-sectional views of the liquid crystal 13 and its periphery in the third embodiment. On the liquid crystal 13, a conductor pattern (strip line) substantially the same as the array antenna 100 'of FIG. 4 is formed by the main line 11 constituting a part of the strip line.
However, slits S1 and S2 that are narrower than the gap G1 are formed at the base portions of the facing portions 11a and 11b, respectively. The slits S1 and S2 are for selectively blocking only a direct current potential through a desired high frequency.

In addition, electrodes 18a and 18b are formed on the insulating film 17 so as to face the opposing portions 11a and 11b in the z-axis direction. The insulating film 17 is laminated to insulate the electrodes 18a and 18b and the ground plate 16 from each other.
6B is a cross-sectional view taken along the line BB ′ shown in FIG. 6A. The electrode 18a is elongated in the y-axis direction in order to obtain a junction point with the lead wiring.
By introducing such electrodes 18a and 18b, an electric field can be selectively and freely formed in the x-axis direction and the z-axis direction of the liquid crystal 13 disposed below and around the gap G1.

FIG. 7 is a circuit diagram of the electric field setting means in the third embodiment. In this circuit, an arbitrary voltage in a range of about 200 _v to 0 _v can be applied between predetermined terminals by a series connection of a DC power source E of about 200 V and a variable resistor R _v .
For example, when the switches SW1 and SW2 are all tilted to the a side, in this case, the terminals P1 and P3 are at the same potential (high potential), and the terminals P2 and P4 are at the same potential (low potential). When the switches SW1 and SW2 are all tilted to the b side, the terminals P1 and P2 are at the same potential (high potential) and the terminals P3 and P4 are at the same potential (low potential).

Therefore, if the terminals P1 to P4 are connected as follows, for example, even with such a circuit configuration (electric field setting means), the direction of each liquid crystal molecule of the liquid crystal 13 can be controlled at a high speed in a desired direction. .
(How to connect each terminal)
Terminal P1: Connects to the opposite part 11a of the strip line Terminal P2: Connects to the electrode 18a Terminal P3: Connects to the opposite part 11b of the strip line Terminal P4: Connects to the electrode 18b

  When such a method is employed, the electrode pair capable of applying an electric field in the x-axis direction is lower (close to the ground plate 16) with respect to the liquid crystal 13 arranged in the lower region of one gap G1. Therefore, the orientation of the liquid crystal molecules of the liquid crystal 13 can be uniformly controlled in the x-axis direction.

FIGS. 8A and 8B are a perspective view and a sectional view of the gap G2 and its periphery in the fourth embodiment. The main features of the fourth embodiment are as follows.
(1) The liquid crystal 23 '(dielectric constant variable member) is not disposed in the dielectric substrate 25 but is disposed on the gap G2 (the one with the larger z coordinate).
(2) The liquid crystal holding member 29 made of a dielectric material surrounds the liquid crystal 23 ′ on the wiring pattern (main lines 21 a, 21 b) on the dielectric substrate 25 or on the dielectric substrate 25 from the side. Are arranged.
(3) Electrodes 28a and 28b (electric field setting means) are formed on the upper surface of the dielectric constant variable member (liquid crystal 23 ') so as to face the wiring patterns (main lines 21a and 21b) in parallel. A gap for beam emission is formed between the electrodes 28a and 28b.

  For example, even if the dielectric constant variable member and the electric field setting means are arranged in this way, a desired electric field can be applied to the dielectric constant variable member (liquid crystal 23 ') in substantially the same manner as in the above embodiments. For example, when the switch SW1 is closed and the switch SW2 is opened, an electric field in the z-axis direction can be formed in the filled region of the liquid crystal 23 ′. When the switch SW2 is closed and the switch SW1 is opened, an electric field in the x-axis direction can be formed particularly in the vicinity of the gap G2 in the filled region of the liquid crystal 23 '.

  In the case of the fourth embodiment, it may be difficult to design the radiation characteristics of the beam in order to consider the influence of the electrodes 28a, 28b, etc., but instead, the dielectric substrate 25 has holes. According to the embodiment like the fourth embodiment, it is possible to obtain an advantage that a desired array antenna can be easily manufactured.

[Other variations]
The embodiment of the present invention is not limited to the above-described embodiment, and other modifications as exemplified below may be made. Even with such modifications and applications, the effects of the present invention can be obtained based on the functions of the present invention.

(Modification 1)
For example, in Embodiment 4 described above, the longitudinal directions of the electrodes 28a and 28b are arranged along the x-axis direction. However, the longitudinal directions of the electrodes 28a and 28b may be arranged along the y-axis direction, respectively. good. In this case, if the main line 21a and the electrode 28a are arranged to face each other in parallel and the main line 21b and the electrode 28b are arranged to face each other in parallel, the radiation amount from each unit pattern is slightly attenuated. Control similar to that in the third embodiment can be realized by using the electric field setting means (FIG. 7) similar to that in the third embodiment.

(Modification 2)
When a planar antenna is configured by arranging a plurality of wiring patterns of the above strip array antenna in parallel, a via hole is formed in the dielectric substrate as necessary, or a multilayer structure is formed in the dielectric substrate. It is necessary to form the necessary control circuit such as the above-mentioned electric circuit in a three-dimensional manner by forming a circuit or wire bonding, but by forming such a three-dimensional circuit, It is also possible to configure a planar antenna by arranging a plurality of wiring patterns of the strip array antenna in parallel in parallel.

  However, in the case of configuring an array antenna in which only one row of the above-described strip array antenna wiring pattern is arranged, the electrical wiring related to the required control circuit is routed on the same plane as the wiring pattern of the strip array antenna. May be. That is, in such a case, it is not always necessary to form the three-dimensional circuit as described above.

  The present invention is useful for wireless communication and electromagnetic wave sensing. For example, an object search for a wireless communication device, an obstacle sensor used in a vehicle accident prevention system, an auto cruise control system, or other objects around the vehicle. It can be used as a means.

The perspective view of the stripline 14 of the array antenna 100 of Example 1. FIG. Partial plan view of array antenna 100 Circuit diagram of electric field setting means of array antenna 100 Graph illustrating radiation beam directivity of array antenna 100 Plan view of array antenna 100 'of the second embodiment Sectional drawing of array antenna 100 'of Example 2 Sectional drawing of the liquid crystal 13 in Example 3 and its periphery Sectional drawing of the liquid crystal 13 in Example 3 and its periphery Circuit diagram of electric field setting means in embodiment 3 The perspective view of gap G2 in Example 4 and its periphery Sectional drawing of gap G2 in Example 4 and its periphery Explanatory drawing explaining the characteristic of the conventional strip array antenna Plan view of other conventional beam scanning antennas Sectional view of other conventional beam scanning antennas

Explanation of symbols

100: Array antenna U: Unit pattern 11: Main line 12: Stub 13: Liquid crystal (variable dielectric constant member)
15: Dielectric substrate G1: Gap

Claims (4)

From a dielectric substrate, a strip line formed by arranging a plurality of identical or similar unit patterns made of conductors in a predetermined direction on the front side of the dielectric substrate, and a conductor formed on the back surface of the dielectric substrate An array antenna having a ground plate comprising:
A dielectric constant variable member whose dielectric constant changes according to a given electric field;
Electric field setting means for applying electric fields from a plurality of directions to the dielectric constant variable member,
The unit pattern is
A transmission line running in the predetermined direction;
A gap for dividing the transmission line in the middle;
A stub branching from the transmission line,
The dielectric constant variable member is:
Arranged close to the gap or the stub,
The electric field setting means includes
An array antenna, wherein different potentials are applied to the conductors forming the unit patterns adjacent to each other in the predetermined direction. The dielectric constant variable member is:
2. The array antenna according to claim 1, wherein the array antenna is made of a liquid crystal, a ferroelectric material, or a ferromagnetic material. The dielectric constant variable member is:
The array antenna according to claim 1, wherein the array antenna is disposed between the unit pattern and the ground plate. The dielectric constant variable member is:
The array antenna according to claim 1, wherein the array antenna is disposed on a surface of the dielectric substrate.

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