JPH0637537A - Linearly polarized wave antenna equipment - Google Patents

Abstract

PURPOSE:To arbitrarily change the direction of linear polarization, namely, the direction of polarization by a small power or manually by rotating a polarization converting element around the center of a metallic plate provided with a radiating element. CONSTITUTION:A polarization converting element 2 has the circular structure, where plural metallic elements 2b are supported by a dielectric 2a, and is rotatably set in a bearing 3a of a supporting body 3. Each metallic element 2b is made of a thin metallic film and is light, and a gear 2c is attached to its outer periphery and is engaged with a gear 6a which is attached to the output shaft of a motor 6 and is paired with this gear 2c. Thus, the polarization converting element 2 is rotated by the motor 6. That is, the polarization converting element 2 consists of a light-weight dielectric 2a and metallic elements 2b and is lighter than a waveguide 4. It is easily rotated by a small power or manually. Since only the polarization converting element 2 is rotated with the waveguide 4 fixed, normal operation is always obtained without applying an unnatural force to the connection part between a feeder and the waveguide 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linearly polarized antenna device in which the direction of polarization can be changed arbitrarily.

[0002]

2. Description of the Related Art Conventionally, as a linearly polarized antenna device, there is a planar type antenna device as shown in FIG. In this type of antenna device, the power from the power supply line 20 is fed into the circular waveguide 21, and the fed power is linearly polarized from the slot 23 cut on the circular metal plate 22 of the circular waveguide 21. Radiated as waves. The direction of this linearly polarized wave (hereinafter referred to as the polarization direction) is limited to one direction. For example, the polarization direction is directed to either the vertical direction V or the horizontal direction H with respect to the ground, depending on the purpose of use.

[0003]

In the conventional linearly polarized antenna device, when the installation posture is determined, the polarization direction is uniquely determined. Therefore, in order to direct the polarization direction to an arbitrary direction, it is necessary to rotate the entire antenna device around the central axis of the circular metal plate 22 (corresponding to the Z axis in FIG. 6). In this case, since the weight of the entire antenna device is large, a considerable amount of power is required to rotate the antenna device.

Further, since the feeder 20 is connected to the circular waveguide 21, the feeder 20 is twisted as the circular waveguide 21 rotates. In an extreme case, the power supply line 20 is disconnected, the power supply to the circular waveguide 21 is stopped, and the linearly polarized wave is no longer emitted. This is a fatal problem for the antenna device.

The object of the present invention is to solve the above problems,
It is an object of the present invention to provide a linearly polarized wave antenna device which can manually change the direction of linearly polarized wave, that is, the direction of polarized wave, manually.

[0006]

In order to achieve the above object, a linearly polarized antenna device according to the present invention is a linearly polarized antenna device in which at least a primary antenna and a polarization conversion element are combined. The antenna has a waveguide and a radiating element, the waveguide is composed of a pair of metal plates, and a metal wall that surrounds the outer periphery thereof, and has a flat transmission space, the radiating element, It is provided on one of the pair of metal plates, radiates the electric power in the transmission space as a circularly polarized wave at the time of transmission, receives the incoming wave of the circularly polarized wave at the time of reception, and guides it into the transmission space. Polarization conversion element
It has at least a plurality of metal elements and a dielectric, is arranged in front of the radiating element, is rotatable about a central axis of a metal plate provided with the radiating element, the plurality of metal elements, Lined up parallel to each other and supported by the dielectric, it causes a phase change in radio waves passing between the metal elements, converts circularly polarized waves from the radiating elements into linearly polarized waves at the time of transmission, and linearly at the time of reception. The incoming wave of polarized waves is converted into circular polarized waves for the radiation element to receive.

[0007]

The function of the polarization conversion element is lighter than the weight of the waveguide because it can be composed of a lightweight dielectric and a metal element. Therefore, the polarization conversion element can be easily rotated with a small power or manually. Since only the polarization conversion element is rotated while the waveguide is fixed, an unreasonable force is not applied to the connecting portion between the power feed line and the waveguide, and the waveguide always operates normally.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view showing an embodiment of the present invention.
However, the motor 6, which is shown in detail in FIGS.
The gears 2c and 6a are omitted. FIG. 2A is an assembly state diagram including the motor 6, the gears 2c and 6a. However, it is a cross-sectional view in the direction perpendicular to the Z axis in FIG. 1. FIG. 2B is a perspective view of the motor 6, gears 2c and 6a, the polarization conversion element 2, and the support 3. FIG. 3 shows one of the plurality of radiating elements 5 of FIG. 1 together with the cross section of the waveguide 4. The linearly polarized antenna device of the present invention will be described below as a transmitting antenna, but it is clear from the reversibility of the antenna that it can be used as a receiving antenna.

In this embodiment shown in FIG. 1, the primary antenna 1
, The polarization conversion element 2 and the support 3 are combined.

The primary antenna 1 comprises a waveguide 4 and a radiating element 5.
It consists of and. The waveguide 4 has a pair of metal plates 4b and 4c, as shown in detail in FIG.
It is composed of a metal wall 4a surrounding these outer peripheries. The space surrounded by these constitutes a hollow transmission space 4d. Here, the height L ₁ of the metal wall 4a is the metal plate 4b, 4
It is shorter than the diameter of c and is (1/2) λ or less. However, λ is a used wavelength. As a result, the transmission space 4d has a flat structure.

The metal plate 4b has two or more small holes 4e. The small hole 4e is provided with a dielectric 5d for supporting the radiating element 5 of FIG. 1, as shown in detail in FIG. Further, the metal plate 4c of FIG. 2 (a) is provided with a power feeding portion 4g at the center thereof. The power feeding unit 4g feeds power into the transmission space 4d. The power supply unit 4g in FIG.
Although a coaxial feeder line is used, it is not limited to this.
For example, a microstrip feed line may be used.

In FIG. 1, a curl antenna (Japanese Patent Application No. 3-163747) is used as the radiating element 5.
The curl antenna 5 is made of metal conductors A to E, as shown in detail in FIG. here,
The portion 5a of the line segment AB of the metal conducting wire is called an electromagnetic coupling portion. In addition, the portion 5b of the line segment CDE of the metal conducting wire is referred to as an electromagnetic wave emitting portion. The portion 5c of the remaining line segment BC is called a coupled coaxial portion.

The electromagnetic coupling portion 5a is inserted in the transmission space 4d as shown in detail in FIG. The electromagnetic wave radiation portion 5b is provided so as to project forward from the metal plate 4b. The curl part from D to E of the electromagnetic wave radiation part 5b has a number of turns of 1 to 1.5 so as to radiate circularly polarized waves, and its outer peripheral length is (3/4) λ <outer peripheral length <( 3 /
2) λ. The coupling coaxial portion 5c has a self-standing structure supported by the dielectric 5d in the small hole 4e of the metal plate 4b. The power supplied from the power supply unit 4g of FIG. 2A into the transmission space 4d is supplied to the electromagnetic coupling unit 5 here.
a is picked up, passes through the coupling coaxial portion 5c,
The electromagnetic wave radiating section 5b radiates circularly polarized waves to the outside.

The support 3 in FIG. 1 is made of a dielectric material having a low dielectric constant, and is provided between the primary antenna 1 and the polarization conversion element 2. The support 3 is shown in FIG.
As shown in detail in FIG. 1, a circular concave bearing 3a is provided to support the rotation of the polarization conversion element 2.

The polarization conversion element 2 of FIG. 1 has a circular structure in which a plurality of metal elements 2b are supported by a dielectric 2a. The dielectric 2a has a low dielectric constant and is light. The dimension L ₂ of the polarization conversion element 2 in the Z-axis direction is about (3/4) λ. Further, the polarization conversion element 2 includes the bearing 3 a of the support body 3.
It is rotatably installed inside. The metal element 2b is made of a thin metal film and is light. The plurality of metal elements 2b are arranged in parallel with each other. As an example of the structural value, when supported by a dielectric 2a close to air, the adjacent metal element 2b is supported.
The distance b is 0.67λ.

A gear 2c is attached to the outer periphery of the polarization conversion element 2 as shown in detail in FIG. 2 (b). The gear 2c meshes with a pair of gears 6a attached to the output shaft of the motor 6. Thereby, the polarization conversion element 2 can be rotated by the motor 6.

Next, the operation principle of the polarization conversion element 2 will be described with reference to FIG. The circularly polarized wave from the primary antenna 1 travels in the Z-axis direction and passes between the adjacent metal elements 2b and 2b. At that time, the phase difference between the two orthogonal components (the component parallel to the length direction of the metal element 2b and the component perpendicular thereto) forming the circularly polarized wave is 90 ° to 0 °. Therefore, on the exit side between the adjacent metal elements 2b, 2b, the combined field of the two orthogonal components becomes a linearly polarized wave. The polarization direction is 45 ° as measured from the length direction of the metal element 2b.

Now, in FIG. 1, it is considered that the polarization direction is directed to a desired direction based on the above-mentioned operation principle. The primary antenna 1 is fixed, and only the polarization conversion element 2 is rotated around the Z axis. At this time, since the direction of the metal element 2b changes, the direction of the linearly polarized wave also changes accordingly. Therefore,
The polarization direction can be directed to a desired direction. In order to change the polarization direction, the polarization conversion element 2 may be rotated around the Z axis by the driving force of the motor 6 as shown in FIG.

2A and 2B, the polarization converting element 2 is rotated by using the motor 6, but the invention is not limited to this. That is, the motor 6 is removed and the polarization conversion element 2
May be rotated directly by hand. Also, the gear 2c
Does not necessarily have to be provided all around the polarization conversion element 2, and may be provided in a range necessary for changing the polarization direction.

The above description is for the case of transmission, but the following is for the case of reception. That is, the polarization conversion element 2 is rotated so that the orientation of the metal element 2b in the longitudinal direction is
It is set to 45 ° with respect to the polarization direction of the incoming linear polarization. Thereby, the linearly polarized wave is converted into the circularly polarized wave and is received by the radiating element 5. This received power is guided into the transmission space 4d and collected in the power feeding unit 4g.

Although the radiating element 5 of the primary antenna 1 is a circularly polarized curl antenna in FIG. 1, it is not limited to this. An electromagnetic coupling portion 5a and a coupling coaxial portion 5c are provided,
A circularly polarized antenna such as a helical one (helical antenna), a spiral one (spiral antenna), a patch one (patch antenna with perturbation), and a loop one (loop antenna with perturbation) as the electromagnetic wave radiating part 5b. It may be. Further, the electromagnetic coupling portion 5a, the coupling coaxial portion 5c
You may use the slot antenna which does not have. In this case, a C-shaped slot is cut in the metal plate 4b and used as the circularly polarized wave radiating element 5.

Although the polarization conversion element 2 of FIG. 1 has a structure of a metal element having a width in the Z-axis direction, the structure is not limited to this. As shown in FIG. 5, an extremely thin pulse-shaped metal element 2b having almost no width in the Z-axis direction.
May be mounted on or vapor-deposited on the dielectric 2a in parallel with each other, and a plurality of these may be stacked in the Z-axis direction to be used as a polarization conversion element. In FIG. 5, there are three layers. This has the same operation as that of the first embodiment. That is, the orthogonal two components of the circularly polarized wave have the same phase as they proceed in the Z axis direction due to the effect of the metal element 2b, and as a result, the circularly polarized wave is converted into the linearly polarized wave. In this case, a gear 2c may be attached to the outer circumference of the polarization conversion element 2 as shown in FIG.

In FIG. 2A, the transmission space 4d has a flat circular cylindrical shape, which is not particularly specified. That is, the metal wall 4a is circular. In order to feed the radiating element 5, the transmission space 4d may have an arbitrary flat shape. For example, the metal wall 4a may have a regular polygonal shape or a flower piece shape (sunflower waveguide).

[0024]

As described above, according to the present invention, since the polarization conversion element is lightweight, it is possible to easily rotate the polarization conversion element to a desired direction by rotating it with a small power or manually. it can.

Further, since the waveguide is fixed and only the polarization conversion element is rotated, an unreasonable force due to a twist is not applied to the connecting portion between the waveguide and the power supply line, and the antenna device is normally operated. You can

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention, in which the motor 6, gears 2c, 6a shown in FIGS. 2 (a) and 2 (b) are omitted.

FIG. 2A is a vertical cross-sectional view in an assembled state including a motor 6, gears 2c, 6a. FIG. 3B is a diagram showing the motor 6, the gears 2 c and 6 a, the polarization conversion element 2, and the support 3.

FIG. 3 shows one of a plurality of radiating elements 5 of FIG.
It is a figure shown with the section of.

FIG. 4 is a principle diagram showing an operation of the polarization conversion element.

FIG. 5 is a perspective view showing another embodiment of the polarization conversion element.

FIG. 6 is a perspective view showing a conventional example.

[Explanation of symbols]

 1 Primary Antenna 2 Polarization Conversion Element 2a Dielectric 2b Metal Element 2c Gear 3 Support 3a Circular Concave Bearing 4 Waveguide 4a Metal Wall 4b, 4c Metal Plate 4d Transmission Space 4e Small Hole 4g Feeding Part 5 Radiating Element 5a Electromagnetic Coupling Part 5b Electromagnetic wave radiating part 5c Coupling coaxial part 6 Motor 6a Gear

Claims (1)

[Claims] 1. A linearly polarized antenna device in which at least a primary antenna and a polarization conversion element are combined, wherein the primary antenna includes a waveguide and a radiating element, and the waveguide forms a pair. A metal plate and a metal wall surrounding the outer circumference of the metal plate are provided, and a flat transmission space is provided.The radiating element is provided on one of the pair of metal plates, and the power in the transmission space is circularly polarized at the time of transmission. It radiates as a wave, and upon arrival, receives an incoming wave of circular polarization and guides it into the transmission space, wherein the polarization conversion element has at least a plurality of metal elements and a dielectric, and the radiation element And is rotatable around a central axis of a metal plate provided with the radiating element, the plurality of metal elements being arranged in parallel with each other and supported by the dielectric. Phase change in radio waves passing between Then, during transmission, the circularly polarized wave from the radiating element is converted into a linearly polarized wave, and at the time of receiving, the incoming wave of the linearly polarized wave is converted into a circularly polarized wave for the radiating element to receive. Characteristic linearly polarized antenna device.