JP3404568B2 - Planar antenna - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat antenna used for satellite broadcasting or data communication, for example.

[0002]

2. Description of the Related Art In a conventional planar antenna used for satellite broadcasting, a radial waveguide is formed by parallel metal plates, and a required number of C-shaped slot pairs are provided on the upper metal plate (see, for example, Japanese Patent Laid-Open Publication No. 2000-242242). (See Sho 57-87603).

In a planar antenna using a dielectric plate, an inner conductor of a coaxial connector is connected to a radiating element by a microstrip line to feed power (see, for example, Japanese Patent Laid-Open No. 8-265038).

[0004]

Problems to be Solved by the Invention JP-A-57-8760
In the configuration of No. 3, it is necessary to cut a large number of slots in the metal plate, which requires machining, shaping and assembling, which requires a large amount of cost and time for manufacturing, and is not suitable for mass production.
In addition, a planar antenna having a hollow structure made of a metal plate has poor mechanical strength and requires careful handling.

Further, since the waveguide is composed of parallel metal plates, current tends to flow uniformly through the metal plates due to the property of the electric circuit. Due to this property, an electric current also flows in a portion of the metal plate where the slot is not cut.

As a result, the current flowing in the portion of the metal plate where the slot is not cut does not contribute to the radiation of the radio waves, so that an energy loss due to the electric resistance of the conductor, that is, a conductor loss is additionally generated. A decrease in efficiency as an antenna is inevitable.

In the plane antenna disclosed in Japanese Patent Laid-Open No. 8-265038, it is necessary to connect the ring-shaped radiating element to the inner conductor of the coaxial connector, and when a large number of radiating elements are used to form an array antenna, the ring-shaped radiating element is used. It is necessary to insert the center conductor connected to the inside of the dielectric, which results in a three-dimensional radiating element pattern, which complicates the manufacturing process.
Further, since the radiating element is fed by the microstrip line, the conductor loss is large and the efficiency as an antenna is reduced.

It is an object of the present invention to provide a planar antenna which has a robust and simple structure, is suitable for mass production, is highly productive, and is more efficient than conventional planar antennas.

[0009]

In order to achieve the above object, in the planar antenna of the present invention, a dielectric plate having a low dielectric loss characteristic is used as a waveguide for guiding an electromagnetic field and masked on the dielectric plate. By plating, printing, pasting, or applying a conductor pattern on the dielectric plate surface as a radio wave radiation element on the surface of the dielectric plate, circularly or linearly polarized radio waves can be generated. Present a planar antenna for transmitting or receiving.

That is, (1) a planar antenna composed of a dielectric plate having a low dielectric loss characteristic, a ground conductor having a coaxial connector for feeding at the center, and a radiating element, The radiating element is composed of the required number of elongated conductors, and the virtual extension line of the longitudinal center axis of all these elongated conductors is
The planar antenna is arranged so as to pass through a reference point on the dielectric plate.

(2) The radiating elements are arranged on a virtual concentric circle with the reference point as the center, and these radiating elements are located in line symmetry with respect to a virtual reference line passing through the reference point, and at the same time. The planar antenna according to the above 1, wherein each of the virtual concentric circles is arranged on only one side with a virtual orthogonal line that is orthogonal to the virtual reference line and passes through the reference point as a boundary.

(3) A constant k determined by the frequency of the electromagnetic field and the permittivity of the dielectric plate with respect to the virtual concentric circle in which the radiating element is arranged in one or both sides of the virtual orthogonal line as a boundary. , One or two constants η (0 ≦ η
≦ 2π) and the radius R of each virtual concentric circle
_j (j = 1, 2, ..., N, n is a positive integer) and the argument of the Hankel function H,

## EQU00007 ## In the planar antenna described in the above 1 and 2, which has a relationship of Arg {H (kR _j )} = η.

(4) On the surface of the dielectric plate, a straight line connecting the point x where the radiating element is arranged and the reference point is formed with respect to an imaginary straight line passing through the reference point. ) And the distance r between the reference point and the point x, and the constant k determined by the frequency of the electromagnetic field and the dielectric constant of the dielectric plate, the deflection angle of the Hankel function H is

## EQU8 ## In the planar antenna described in the above 1, the relationship of θ = Arg {H (kr)} is satisfied.

(5) The grounding conductor is arranged on one surface of the dielectric plate having a low dielectric loss characteristic, and the required number of radiating elements made of strip-shaped conductors are arranged on the opposite surface, and the grounding conductor is grounded. A planar antenna in which a coaxial connector for power supply is arranged in the center of a conductor, and a virtual extension line of the central axis of the coaxial connector and a surface on which a radiating element is arranged are set as reference points, and all The virtual extension line of the longitudinal center axis of the strip conductor is arranged so as to pass through the reference point, and the midpoint of the longitudinal center axes of all the strip conductors is a virtual concentric circle with the reference point as the center. At the same time, all strip-shaped conductors are arranged in line symmetry with the virtual reference line on the surface of the dielectric plate passing through the reference point as the axis of symmetry, and on each virtual concentric circle, Boundary is a virtual orthogonal line on the surface of the dielectric plate that is orthogonal to the reference line. A, is disposed only on one side of each of the radius R _j of virtual concentric circle thereof strip-shaped conductor is disposed _{(j = 1,2, ..., n} , n is a positive integer) is , A constant k determined by the frequency of the electromagnetic field and the permittivity of the dielectric plate, between the argument of the Hankel function H and

## EQU00009 ## Using two constants .zeta. And .xi. In the relationship of .zeta .-. Xi. =. Pi., Each of the imaginary concentric circles in which the radiating element in the region on one side is arranged with the virtual orthogonal line as the boundary For radius R _j of

Arg {H (kR _j )} = ζ (0 ≦ ζ ≦ 2π), and for each radius R _j of the virtual concentric circles in which the radiating elements in the other region are arranged,

(11) Arg {H (kR _j )} = ξ (0 ≦ ξ ≦ 2π), which is a planar antenna characterized by being related.

(6) The grounding conductor is arranged on one surface of the dielectric plate having a low dielectric loss characteristic, and a required number of radiating elements made of strip-shaped conductors are arranged on the opposite surface, and the grounding conductor is grounded. A planar antenna in which a coaxial connector for power supply is arranged in the center of a conductor, and a virtual extension line of the central axis of the coaxial connector and a surface on which a radiating element is arranged are set as reference points, and all The virtual extension line of the longitudinal center axis of the strip conductor is arranged so as to pass through the reference point, and the straight line connecting the midpoint x of the strip conductor longitudinal center axis and the reference point is the reference point. Angle θ with respect to an imaginary straight line on the surface of the dielectric plate
Between the (radiance method), the distance r between the reference point and the point x, and the declination of the Hankel function H, a constant k determined by the frequency of the electromagnetic field and the dielectric constant of the dielectric plate is used.

[Equation 12] θ = Arg {H (kr)} It is in a planar antenna characterized by the following relationship.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings based on examples. For convenience of explanation, the planar antenna of the present invention will be described as a transmitting antenna.
It is clear that by the reciprocity theorem of the electromagnetic field, it only works in reverse for reception. Unless otherwise specified, the unit of phase and angle is radian.

The radiating element of the planar antenna of the present invention,
The elongated conductor or the strip conductor refers to a conductor having a thin thickness as shown in FIG. 2, and the central axis in the longitudinal direction is represented by L ₁ . The midpoint of the central axis of the longitudinal direction refers to the intersection of straight lines L ₂ and L ₁ which are orthogonal to the central axis L ₁ of the longitudinal direction and equally divide the elongated conductor or the strip conductor.

In the planar antenna of the present invention, the coaxial connectors 4, 28, 54 are connected to the dielectric plates 1, 10, 20, 51.
The electromagnetic field introduced to the inside of the coaxial connector 4, 28, 5
The dielectric plates 1, 10, 20, 2 are mathematically represented by the Hankel function of the second kind in an axially symmetric mode with the conductors 5, 29, 55, 58 connected to the inner conductors of 4 as axes of symmetry.
The inside of 1, 51 is a radial waveguide, and propagates in the form of a cylindrical wave in the radial direction.

Generally, in a planar antenna that constitutes and utilizes a radial waveguide as in the present invention, the direction of the electromagnetic field inside the waveguide is that the magnetic field exists only in the circumferential direction. , The current tries to flow in the conductor in the radial direction of the circle.

FIG. 5 shows the dielectric plates 1, 10, 20, 21,
5 is a diagram schematically illustrating an electromagnetic field inside 51, showing an electromagnetic field propagating as a cylindrical wave with a symmetry axis being an axis perpendicular to the dielectric plate and passing through a reference point, and showing an electric field e by a dotted line. h
Is shown by a solid line.

In the radiating elements 3, 11, 23 and 53 of the planar antenna according to the present invention, since the central axis in the longitudinal direction passes through the reference point, the magnetic field inside the dielectric plate is represented as shown in FIG. Since the radiating element is arranged in a direction perpendicular to the radiating element, the radiating element has a current i ₁ as shown by an arrow in FIG.
i ₂ is oriented in the direction in which it easily flows.

Further, in the planar antenna according to the present invention,
A dielectric waveguide is used, and the currents other than the currents flowing through the ground conductors 2, 22, 52 are the currents that contribute to the emission of radio waves,
That is, since most of the current flows through the radiating elements 3, 11, 23, 53, the energy loss due to the electric resistance of the conductor is suppressed to the minimum, and the efficiency of the antenna is improved.

That is, the conductor loss is reduced by using the dielectric radial waveguide, and the radiating elements 3, 11, 23 and 53 are arranged in the direction in which the current flows most easily, so that the radio wave can be efficiently transmitted. Is emitted.

3 and 4 show a basic embodiment of the planar antenna according to the present invention. 3 and 4, the electromagnetic field propagates as a cylindrical wave inside the dielectric plate 1 with the linear conductor 5 as the axis of symmetry in the axially symmetric mode, so that the surface of the dielectric plate 1 on the central axis of the coaxial connector 4 When the radiating elements 3 are arranged so that the midpoints of the longitudinal center axes of the individual elongated radiating elements are located on a virtual concentric circle centered on the reference point, the radiating elements 3 on the same circumference of the virtual concentric circle are arranged. The phases of the radio waves radiated from will be temporally coincident.

FIG. 6 is a drawing for explaining the arrangement of the radiating element 3 which radiates a linearly polarized wave. Vectors of radio waves emitted by the radiating elements A, B, C, and D at sufficiently distant points are A ′, B ′, C ′, and D ′, respectively. A, B, C are reference points O
Are arranged on the same circumference of an imaginary concentric circle centered at, and B is line-symmetric with respect to A and the virtual reference line VSL, and C is A.
Is symmetric with respect to a virtual orthogonal line VVL orthogonal to the virtual reference line VSL. Further, D is a position where the radiating element of C is shifted in the radial direction by half the wavelength in the dielectric plate.

Radio waves radiated from the radiating elements located on the same circumference of the virtual concentric circles as shown in A and B of FIG. 6 and symmetrical to the virtual reference line VSL are represented by vectors A'and B '. As described above, the components perpendicular to the virtual reference line VSL cancel each other out, and the parallel components are added together.
C is a radiating element located at a position symmetrical to A with respect to the virtual orthogonal line VVL, and radiates a radio wave that cancels a radio wave component parallel to the virtual reference line VSL of the vector A ′, like the vector C ′. To do.

Therefore, the virtual reference line V of the vector A '
In order to use the component parallel to SL, it is not preferable that the radiating element is located at the position of C, and on the same circumference of the virtual concentric circle, it is line symmetric with respect to the virtual reference line VSL,
When the radiating element is disposed on either side of the virtual orthogonal line VVL as a boundary, linearly polarized radio waves can be used.

In a planar antenna using an electromagnetic field of an axially symmetric mode, in general, an electromagnetic field propagates in a dielectric while maintaining the shape of the same size and the same phase on the same circumference. It is desirable from the viewpoint of directivity characteristics. At this time, if the radiating elements 3, 11, 23 and 53 are present, the electromagnetic field energy is radiated by the radiation of the radio wave,
The electromagnetic field in the dielectric plates 1, 10, 21, 51 becomes small.

Therefore, in order to maintain the axially symmetric mode, it is preferable that the density per area of the radiating elements 3 on the surface of the dielectric plate 1 be uniform over the entire surface of the dielectric plate 1. Therefore, the radiating elements 3 arranged according to the above rule as shown in FIG. 3 are arranged in a pattern closer to the uniform arrangement density. It is preferable that the right and left are arranged alternately.

In order for the radio waves in the virtual reference line direction to be added together, the phases of the radio waves radiated from the radiating element 3 must be the same.

The phase of the electromagnetic field of the axially symmetric mode propagating inside the dielectric plates 1, 10, 20, 21, 51 is mathematically expressed as
It is represented by the argument of the Hankel function of the second kind with the radial distance as the independent variable. The argument of the Hankel function H has its real part a and its imaginary part b.

## EQU13 ## This is defined by Arg {H} = tan ^-1 (b / a).

Therefore, the radiating element 3 on the surface of the dielectric plate 1 is
Each radius R _j of the virtual concentric circles (j = 1, 2, ...,
n, n is a positive number) and a constant k determined by the frequency of the electromagnetic field and the dielectric constant of the dielectric plate 1 is used to determine the difference between the argument of the Hankel function H and the constant η (0 ≦ η ≦ 2π). ,

If the radiating element 3 is arranged on a virtual concentric circle having a radius R _{j with} a constant declination so that Arg {H (kR _j )} = η holds, the radiated radio wave will have time. Are in phase with each other. For the reason explained in FIG. 6, in order to radiate a linearly polarized wave, the radius R _j
In each of the virtual concentric circles configured by, the radiating element is arranged on either side with the virtual orthogonal line as a boundary.

The constant k used here is a constant called electromagnetic wave number, and when the frequency of the electromagnetic field is f and the permittivity and permeability of the substance are ε and μ, respectively.

[Expression 15] k = 2πf√ (εμ) For example, the wave number inside a substance having a frequency of 12 GHz and a relative permittivity of 2 is 355.68. Here, the relative dielectric constant is the dielectric constant in vacuum of 8.8542.
^Is the ratio of the dielectric constant of the substance to × 10 ⁻¹² ,
It becomes a value of 1 or more.

Due to the nature of the Hankel function, the dielectric plates 1, 1
Although the wavelength of the electromagnetic field inside 0, 20, 21, 51 changes slightly, it may be regarded as constant in practice. Therefore, assuming that the wavelength of the electromagnetic field inside the dielectric plates 1, 10, 20, 21, 51 is constant, calculation of the Hankel function is not necessary, and the radius can be represented by the arithmetic progression and the virtual concentric circle can be set. .

Using the dielectric constant ε of the dielectric plates 1, 10, 20, 21, 51 and the wavelength λ of the electromagnetic field in free space, the tolerance d
To

[Equation 16] A radius is expressed by using an arithmetic sequence with d = λ / √ε, and virtual concentric circles are formed on each side of the virtual orthogonal line as a boundary or in the entire area on the dielectric plate surface. A radiating element may be provided.

In order to radiate linearly polarized waves efficiently, regarding the radio waves radiated from the left and right of the virtual orthogonal line,
It is desirable that the components in the virtual reference line direction are added together. However, when the radiating elements are located on the same circumference on the virtual concentric circle and the positional relationship is symmetric with respect to the virtual orthogonal line,
Like the vector A ′ and the vector C ′ in FIG. 6, their phases temporally coincide with each other and spatially have a phase difference of π, so that the components in the virtual reference line direction cancel each other out. Become. Therefore, in order to be added together, the radiating element 3 arranged on the left with the virtual orthogonal line as a boundary.
The radio wave radiated from the radio wave and the radio wave radiated from the radiating element 3 arranged on the right need to have a phase difference of π with respect to time so that the phases are spatially matched.

A radio wave radiated from the radiating element 3 arranged on the left and a radio wave radiating from the radiating element 3 arranged on the right with respect to the virtual orthogonal line as a boundary, have a temporal phase difference of π. To have

Using the constants ζ and ξ having the relationship of ζ−ξ = π, the deflection angle of the above Hankel function is related to the radius and the constant of each virtual concentric circle on both sides of the virtual orthogonal line, and the radiating element 3 To arrange. That is, each radius R of the virtual concentric circles in which the radiating elements in one region are arranged with the virtual orthogonal line as a boundary
_{For j} (j = 1, 2, ..., N, n is a positive integer),

Where Arg {H (kR _j )} = ζ (0 ≦ ζ ≦ 2π), and for each radius R _j of the virtual concentric circle in which the radiating elements in the other region are arranged,

If Arg {H (kR _j )} = ξ (0 ≦ ξ ≦ 2π), there is a phase difference of π in terms of time.

For the same reason as above, the dielectric plates 1, 10, 2 are
Assuming that the wavelengths of the electromagnetic fields inside 0, 21, and 51 are constant, the above relationship can be simply expressed using an arithmetic sequence. Using the permittivity ε of the dielectric plates 1, 10, 20, 21, 51 and the wavelength λ of the electromagnetic field in free space, the radius of the circle with the smallest radius is taken as the first term, and the tolerance d is

[Equation 20] Radius is represented by an arithmetic progression with d = λ / (2√ε), virtual concentric circles are formed around a reference point, and virtual concentric circles are radiated alternately from left and right in order from a virtual concentric circle with a small radius. The element 3 may be provided. Here, λ / √ε is the dielectric plate 1, 10, 20, 21, 51
It is the wavelength of the electromagnetic field inside.

In FIG. 6, the radiating elements A and D arranged on the virtual concentric circle configured as described above have a temporal phase difference of π. Therefore, the radio wave components of the vector A ′ and the vector D ′ in the virtual reference line VSL direction are added together, and the linearly polarized radio wave is efficiently radiated in the virtual reference line VSL direction. The pattern of the radiating element 3 in FIG. 3 is an embodiment constructed by using the above method, and radiates a linearly polarized radio wave.

FIG. 7 shows an embodiment of the pattern of the radiating element 11 which radiates circularly polarized radio waves. An electromagnetic field propagating inside the dielectric plate 10 in the axially symmetric mode causes a current having a phase corresponding to the phase of the internal electromagnetic field to flow in the radiating element 11, so that the current is deviated about the reference point according to the declination of the Hankel function. If the radiating elements 11 are sequentially arranged at positions rotated by an angle, circularly polarized radio waves are radiated.

FIG. 8 is a diagram for explaining the rules for arranging the circularly polarized radiation element, wherein the radiation elements S ₁ , S ₂ , and S ₃ are from the reference point S and the angle with respect to the virtual straight line VL. The distances are respectively arranged at positions of φ, r ₁ , ψ, r ₂ , χ, r ₃ . At this time, using the constant k determined by the dielectric constant of the dielectric plate 10 and the frequency of the electromagnetic field, the deviation angle of the Hankel function H is

## EQU20 ## Arg {H (kr ₁ )} = φ

## EQU21 ## Arg {H (kr ₂ )} = ψ

## EQU22 ## Radiating elements are arranged in a relationship of Arg {H (kr ₃ )} = χ.

The rule for disposing the circularly polarized wave radiating element is based on the same principle as in JP-A-57-87603, but the radiating element is formed on a metal plate in JP-A-57-87603. It is a pair of V-shaped slots, and is a strip conductor on a dielectric plate in the planar antenna according to the present invention. Further, in Japanese Patent Laid-Open No. 57-87603, all slots form an angle of π / 4 with respect to the radial direction, whereas in the present invention, the central axis in the longitudinal direction of all elongated or strip-shaped conductors is in the radial direction. The difference is that they match. In addition, JP-A-57-8
If the longitudinal center axis of any of the slots of 7603 coincides with the radial direction, the slot cannot be an effective radio wave emitting element electromagnetically.

For the same reason as above, assuming that the wavelength of the electromagnetic field in the dielectric plate 10 is constant, the pattern of the radiating element 11 that radiates the circularly polarized wave is constructed by using the spiral of Archimedes. be able to.

That is, the radiating element is arranged on the virtual Archimedean spiral constructed by the rule that the distance from the center increases by the length λ / √ε of the wavelength in the dielectric plate 11 every one rotation. Arrange. Mathematically, for any Archimedes' spiral, the distance t between the point G and the point y is defined by an arbitrary straight line passing through the point G and an angle α (radian measure) formed by the straight line connecting the point G and the point y. In between, using an arbitrary constant K,

T = Kα When the above rule is applied, the constant K becomes

K = λ / (2π√ε) Becomes

That is, in order to arrange the radiating element 11 by the spiral of virtual Archimedes, the above α is replaced with φ, ψ, χ in FIG. 8, and the above t is r ₁ , r ₂ , in FIG.
Replace with r ₃ .

It is clear that it is necessary to change the direction of rotation of the virtual Archimedean spiral depending on the direction of circular polarization, that is, right-handed polarization and left-handed polarization.

FIG. 4 is a sectional view taken along the line II 'of the planar antenna for radiating linearly polarized waves of the embodiment shown in FIG. A wire connected to the inner conductor of the coaxial connector 4 is provided with a coaxial connector 4 for supplying power with a coaxial cable, with the power supply point being directly below the reference point on the surface of the dielectric plate 1 on which the radiating element 3 is arranged. The conductor 5 is connected to the circular conductor 6.

The linear conductor 5 and the circular conductor 6 are impedance-matched at the feeding point to reduce reflection of an electromagnetic field.
The electromagnetic field is efficiently guided into the dielectric plate 1.

Therefore, the length, thickness and shape of the linear conductor 5 and the size of the circular conductor 6 are appropriately adjusted depending on the frequency of the electromagnetic field and the thickness of the dielectric plate 1. If impedance matching can be achieved, the circular conductor 6 may be omitted, and the linear conductor 5 need not be connected to the circular conductor 6.

The matching load 7 is for suppressing the reflection of the electromagnetic field at the end of the dielectric plate 1, and may be omitted when the reflection at the end is small.

As an alternative to the linear conductor 5, a shape shown in FIG. 9 is effective for impedance matching.

The two-stage tapered conductor 29 shown in FIG. 13 is an embodiment in which it is connected to a coaxial connector as an alternative to the linear conductor 5, and the conductor having the shape shown in FIG. This is effective for impedance matching over the entire length.

As shown in the cross-sectional view of the feeding point of FIG. 10, it is also possible to provide a tapered convex portion at the feeding point of the dielectric plate 1 and connect the coaxial connector using the joining metal fitting 57. Effective for alignment.

As shown in FIG. 11, it is also effective to provide a stub that can move up and down and adjust the stub for impedance matching.

12 and 13 show an embodiment in which the directional characteristics of the planar antennas shown in FIGS. 3 and 4 are improved.
An electromagnetic field is caused to wrap around the upper dielectric plate 21 and a radio wave is radiated. With this configuration, the arrangement density of the radiating elements is closer to the outside of the dielectric plate 21 where the electromagnetic field inside is stronger than to the inside, so that the characteristics of the antenna can be improved.

FIG. 12 shows an example of a pattern of a radiating element that radiates circularly polarized waves. Further, FIG. 13 shows II- of FIG.
FIG. 11 is a sectional view taken along line II ′. The intermediate circular conductor 30 for guiding the electromagnetic field to the end of the dielectric plate 20 has two dielectric plates 20, 21.
It is provided at the boundary of. Then, the dielectric plates 20 and 21
The side surface is connected to the ground conductor 22, and the lower side surface conductor 24, the upper side surface conductor 25, and the annular conductor 26 form a waveguide for guiding the electromagnetic field to the upper dielectric plate 21.

In this structure, the ends of the dielectric plates 20 and 21 need to have a shape suitable for guiding electromagnetic waves to the upper layer, and the intermediate circular conductor 30, the lower side conductor 24, the upper side conductor 25, and the annular conductor. 26, and the dielectric plate 20,
The thickness of 21 and the cross-sectional shape of the end are appropriately adjusted.

The matching load 27 is a matching load 27 for absorbing the energy of the electromagnetic field that is not radiated as a radio wave among the electromagnetic fields propagating from the outside to the inside of the dielectric plate 21. When the antenna is sufficiently large and the number of radiating elements 23 is large, or when the shape of the radiating elements 23 is devised so that the radiation efficiency of the radiating elements is sufficiently high, the internal electromagnetic field of the dielectric plate 21 is , The matching load 27 is not necessary because it is sufficiently small in the central portion.

Even in a pattern that radiates a linearly polarized wave,
The characteristics can be improved by adopting the configuration of FIGS.

In the antenna according to the present invention, the elongated or strip-shaped radio wave radiation element has a shape as shown in the embodiment of FIG. 14 or a combination thereof in order to make the radiation efficiency of the radio wave appropriate. May be.

When a large amount of power is required or when it is necessary to electrically change the directivity, a required number of planar antennas according to the present invention may be used to form an array antenna.

A protective structure such as a radome may be appropriately provided on the surface of the antenna to protect the radiating element pattern.

[0063]

Since the planar antenna of the present invention is constructed as described above, it has the following effects.

Since the use of the conductor which causes the energy loss is the planar antenna which is suppressed to the minimum, the efficiency as the antenna becomes high.

Since all are integrated with a dielectric and are composed of only planes, like a planar antenna having a hollow structure and a parabolic antenna used for satellite broadcasting,
It is much more robust and mechanically stronger than an antenna that has a curved structure and must support the primary radiator of the feeding point at a specific position.

Since it is a plane antenna, when it is installed outdoors, it is less susceptible to the effects of wind and snow and is more durable than an antenna having a three-dimensional structure like a conventional satellite dish for satellite broadcasting.

Most of the conductors arranged on the dielectric plate are two-dimensionally arranged in a plane and can be arranged at a time by patterning, so that the manufacturing time and the manufacturing cost are reduced. The antenna is suitable for mass production.

Both the plane antenna for circular polarization and the plane antenna for linear polarization have the same structure, and it is possible to manufacture the plane antenna with the polarized wave changed only by changing the pattern of the radiating element. Can be held down.

[Brief description of drawings]

FIG. 1 is a bird's-eye view clearly showing the internal structure, showing the basic configuration of a planar antenna according to the present invention.

FIG. 2 is a diagram illustrating a shape and a central axis of a radiating element of a planar antenna according to the present invention.

FIG. 3 is a front view of a planar antenna in an embodiment showing a pattern of a radiating element that radiates a linearly polarized wave of the planar antenna according to the present invention.

4 is an embodiment showing a basic internal structure of the planar antenna according to the present invention, and is a cross-sectional view taken along the line II ′ of the front view of FIG. 3. FIG.

FIG. 5 is a view for explaining a mode of an electromagnetic field inside a dielectric to show an operating mechanism of the planar antenna according to the present invention.

FIG. 6 is a diagram illustrating an arrangement rule of radiating elements that radiate linearly polarized waves of the planar antenna according to the present invention.

FIG. 7 is a front view of a plane antenna in an example showing a pattern of a radiating element that radiates circularly polarized waves of the plane antenna according to the present invention.

FIG. 8 is a diagram illustrating a layout rule of radiating elements that radiate circularly polarized waves of the planar antenna according to the present invention.

FIG. 9 is an example in which a linear conductor and a tapered conductor are modified.

FIG. 10 is a perspective view showing a tapered convex portion provided on a feeding portion of a dielectric plate.
FIG. 6 is an enlarged cross-sectional view of a power feeding unit in an embodiment in which impedance matching at a power feeding point is improved.

FIG. 11 is an enlarged cross-sectional view of a power feeding unit in an embodiment in which impedance matching at a power feeding point is improved by using a stub.

FIG. 12 is a front view of an embodiment in which the planar antenna of FIGS. 3 and 4 is improved.

13 is a cross-sectional view taken along line II-II ′ of the front view of FIG. 12, showing an embodiment showing the internal structure of FIG.

FIG. 14 is an example in which the shape of the radiating element is modified.

[Explanation of symbols]

1, 10, 20, 21, 51 Dielectric plate 2, 22, 52 Ground conductor 3, 11, 23, 53 Radiating element 4, 28, 54 Coaxial connector 5, 55 Linear conductor 6, 12, 56 Circular conductor 7, 27 Matched Load 8 Direction of Linearly Polarized Wave 24 Lower Side Conductor 25 Upper Side Conductor 26 Annular Conductor Layer 29 Two-Step Tapered Conductor 30 Intermediate Circular Conductor 40 Stub 57 Joining Metal 58 Tapered Conductor 59 Coaxial Connector Inner and Outer Conductor Dielectric filling space

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Claims (6)

(57) [Claims] 1. A flat antenna comprising a dielectric plate having a low dielectric loss characteristic, a ground conductor having a coaxial connector for feeding at the center, and a radiating element, wherein the radiating element is required. Planar antenna, characterized in that it is composed of a number of elongated conductors, and that virtual extension lines of the longitudinal center axes of all these elongated conductors are arranged so as to pass through a reference point on the dielectric plate. . 2. Radiating elements are arranged on a virtual concentric circle centered on a reference point, and these radiating elements are located in line symmetry with respect to a virtual reference line passing through the reference point, and at the same time, respective virtual concentric circles. 2. The planar antenna according to claim 1, wherein the planar antenna is arranged only on one side with a virtual orthogonal line that is orthogonal to the virtual reference line and passes through the reference point as a boundary. 3. A constant k determined by the frequency of the electromagnetic field and the dielectric constant of the dielectric plate with respect to a virtual concentric circle in which the radiating elements are arranged in one or both sides of the virtual orthogonal line as a boundary.
And one or two constants η (0 ≦ η ≦ 2π), the radii R _j (j = 1, 2, ...
3. n and n are positive integers), and the argument of the Hankel function H has a relationship of Arg {H (kR _j )} = η. Plane antenna. 4. The angle θ (radiance method) formed by a straight line connecting a point x where a radiating element is arranged and a reference point on a dielectric plate surface with respect to an imaginary straight line passing through the reference point, and a reference Using the distance r between the points and the point x and the constant k determined by the frequency of the electromagnetic field and the permittivity of the dielectric plate, the deviation angle of the Hankel function H is expressed as follows: θ = Arg {H (kr)} The planar antenna according to claim 1, wherein the planar antenna has the following relationship. 5. A grounding conductor is arranged on one surface of a dielectric plate having a low dielectric loss characteristic, and a required number of radiating elements made of strip-shaped conductors are arranged on opposite surfaces, and a central portion of the grounding conductor. A planar antenna in which a coaxial connector for power feeding is arranged in the center of the coaxial connector, and the intersection of the virtual extension line of the central axis of the coaxial connector and the surface on which the radiating element is arranged is used as a reference point for all rectangular conductors. The virtual extension line of the longitudinal center axis of is arranged so as to pass through the reference point, and the midpoints of the longitudinal center axes of all the strip conductors are located on a virtual concentric circle centered on the reference point. , At the same time, all strip-shaped conductors are arranged at positions symmetrical about the virtual reference line on the surface of the dielectric plate that passes through the reference point and are orthogonal to the virtual reference line on each virtual concentric circle. With the virtual orthogonal line on the surface of the dielectric plate Is disposed only on the side of each of the radius R _j of virtual concentric circle thereof strip-shaped conductor is disposed _{(j = 1,2, ..., n} , n is a positive integer) is the Hankel function H Using the constant k determined by the frequency of the electromagnetic field and the permittivity of the dielectric plate and the two constants ζ and ξ in the relationship of ζ−ξ = π, the virtual orthogonality For each radius R _j of the virtual concentric circles in which the radiating elements on one side are arranged with the line as the boundary, Arg {H (kR _j )} = ζ (0 ≦ ζ ≦ 2π), and for each radius R _j of the virtual concentric circles in which the radiating elements in the other region are arranged, Arg {H (kR _j )} = ξ (0 ≦ ξ ≦ 2π), a planar antenna characterized by being related. 6. A grounding conductor is arranged on one surface of a dielectric plate having a low dielectric loss characteristic, and a required number of radiating elements made of strip-shaped conductors are arranged on the opposite surface, and a central portion of the grounding conductor. A planar antenna in which a coaxial connector for power feeding is arranged in the center of the coaxial connector, and the intersection of the virtual extension line of the central axis of the coaxial connector and the surface on which the radiating element is arranged is used as a reference point for all rectangular conductors. A virtual extension line of the central axis of the longitudinal direction of the strip conductor is arranged so as to pass through the reference point, and a straight line connecting the midpoint x of the longitudinal central axis of the strip conductor and the reference point passes through the reference point. The angle θ (degree of arc method) with respect to the virtual straight line on the plate surface,
Between the distance r between the reference point and the point x and the declination of the Hankel function H, a constant k determined by the frequency of the electromagnetic field and the permittivity of the dielectric plate is used, and θ = Arg {H (Kr)} A planar antenna characterized by the following relationship.