JP3470184B2 - 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 microwave band flat antenna used in, for example, satellite broadcasting, data communication and mobile communication.

[0002]

2. Description of the Related Art A conventional planar antenna used in the microwave band is constructed by forming a radial waveguide with parallel metal plates and providing a required number of C-shaped slot pairs on the upper metal plate (see, for example, (See Kai 57-87603).

In a planar antenna using a dielectric plate as a waveguide, elongated conductors are used as radiating elements, and the extension lines of the central axes of the elongated conductors in the long axis direction pass through a reference point on the dielectric plate. By arranging in such a manner (for example, Japanese Patent Application No. 1
1-377398).

[0004]

Problems to be Solved by the Invention JP-A-57-8760
In the planar antenna having the structure of No. 3, it is necessary to precisely assemble and assemble a metal plate having a large number of slots cut into a flat cylindrical shape, which requires a large amount of cost and time to manufacture. In addition, since it has a hollow structure, it has poor mechanical strength.

In general, most of the energy loss generated in the antenna is conductor loss due to the electric resistance of the conductor. An antenna that uses a slot as a radiating element has a large amount of current that does not contribute to the radiation of radio waves flowing through a metal portion, has a larger conductor loss than an antenna that uses a dielectric, and is inferior in antenna efficiency.

In the planar antenna disclosed in Japanese Patent Application No. 11-377398, in the case of a radiation element pattern that radiates circularly polarized waves, when considering instantaneous radiation, circularly polarized radio waves are radiated from the entire antenna surface. However, there is a deviation in the radiation intensity distribution on the antenna surface, which is a drawback that sufficient gain cannot be obtained.

It is an object of the present invention to provide a planar antenna using a dielectric plate as a waveguide, which is superior in efficiency and gain to the conventional planar antenna due to its robust and simple structure.

[0008]

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 presenting a conductor pattern on the surface of a dielectric plate as a radio wave radiating element by plating, printing, pasting, or applying a conductor pattern, a highly efficient planar antenna is presented.

That is, (1), a required number of radiating elements are arranged on one surface of a dielectric plate having a low dielectric loss characteristic, a ground conductor is arranged on the other surface of the dielectric plate, and A planar antenna having a structure in which power is fed from the center of a conductor, and each radiating element is composed of one or two elongated conductors,
When one radiating element is composed of two elongated conductors, the long-axis central axis and the short-axis central axis of either one of the elongated conductors Using the constant k determined by the constant and as the argument of the Hankel function H,

Equation 7] In the relationship of θ = Arg {H (kr x )}, the distance between the intersection y and the reference point a of the long axis direction center axis of the other elongated conductor and short axis center axis r _y is the wavelength λ of the surface wave of the dielectric plate,

0 <r _x −r _y <λ / 2 η and an angle δ formed by the extension lines of the central axes of the two elongated conductors are larger than 0 radians and smaller than π radians, and one radiating element is composed of one elongated conductor. If the radiating element is used, the radiating element is composed of either one of the two elongated conductors having the point x or the point y, and all the radiating elements are not directly fed but the electromagnetic field inside the dielectric plate. Is a planar antenna characterized by being coupled with electromagnetic induction and radiating radio waves.

(2) The extension lines of the central axes of the two elongated conductors of the two elongated conductors constituting one radiating element are orthogonal to each other, and the central axes of the elongated conductors of the elongated conductors are in the longitudinal direction. And the points s and t at the intersections of the center axis line with the minor axis direction and the reference points b. And between r _s and r _t ,

[Equation 9] r _s -r _t = λ / 4 The flat antenna according to the above 1, wherein the angles between them are equal.

(3) A required number of radiating elements are arranged on one surface of the dielectric plate having a low dielectric loss characteristic, a ground conductor is arranged on the other surface of the dielectric plate, and A planar antenna having a structure in which power is fed from the center of a conductor, one radiating element is composed of one elongated conductor, and all radiating elements are on a dielectric plate surface on which the radiating element is arranged. It is located in line symmetry with respect to an imaginary reference line passing through the reference point q, and with the reference point q as the center, radii Ri, Rj (i, j =
1, 2, 3, ... N, n is a positive integer), using a constant k determined by the frequency of the electromagnetic field and the electromagnetic material constant of the dielectric plate,

[Mathematical formula-see original document] Between the two constants ζ and ξ in the relationship of ζ−ξ = π, as the angle of deviation of the Hankel function H (the arc method),

Arg {H (k Ri)} = ζ (0 ≦ ζ
≦ 2π)

## EQU12 ## Arg {H (k Rj)} = ξ (0 ≦ ξ
All radiating elements are arranged on the virtual concentric circle group represented by the relation of ≦ 2π), and at the same time, the radiating elements on each virtual concentric circle are virtual orthogonal orthogonal to the virtual reference line and passing through the reference point q. It is arranged only on either side of the line as a boundary, the longitudinal central axes of all the radiating elements are parallel to the virtual reference line, and all the radiating elements are not directly fed, Coupled by electromagnetic induction and electromagnetic field inside the dielectric plate,
It is a planar antenna characterized by emitting radio waves.

[0012]

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 phase and angle are represented by the radian method, and the unit is radian.

As shown in FIG. 2, the straight side L ₁ parallel to the long side obtained by equally dividing the short side of the elongated conductor is defined as the central axis of the elongated conductor in the long axis direction. Is divided into equal parts and a straight line L ₂ parallel to the short side is defined as the center axis of the short axis direction.

The argument Arg {H} of the Hankel function H has a real part Re {H} and an imaginary part Im of the Hankel function H.
When {H}, using the arctangent function,

Arg {H} = tan ⁻¹ [Im {H} /
Re {H}].

FIG. 1 shows the basic structure of the planar antenna of the present invention. The electromagnetic field introduced from the coaxial connector 4 into the dielectric plate is concentrically dielectric with the central conductor of the coaxial connector as the axis of symmetry. It propagates in the body plate 1 in the surface wave mode.

Mathematically, the mode of propagation of the electromagnetic field inside the dielectric plate is expressed using the Hankel function. Therefore, when the electromagnetic field advances inside the dielectric plate, the phase of the electromagnetic field changes by the amount represented by the deflection angle of the Hankel function. If the radiating element is arranged at a position separated from the center by the distance traveled in the dielectric plate by rotating by the argument of the function,
Circularly polarized radio waves are radiated from the radiating element group arranged according to this rule.

The wavelength λ of the electromagnetic field inside the dielectric plate is determined by the frequency of the electromagnetic field and the electromagnetic material constant of the dielectric. If the frequency of the electromagnetic field is ν and the permittivity and permeability of the substance are ε and μ, respectively,

The constant k represented by k = 2πν√ (εμ) = 2π / λ is called a wave number and is a constant characterizing the propagation of the electromagnetic field. On the surface of the dielectric plate, the wavelength is different between the inside and outside of the dielectric plate, but it is derived from the electromagnetic field theory that the wavelength of the electromagnetic field in the tangential direction to the surface of the dielectric plate is the same inside and outside the dielectric, The wave of the electromagnetic field in the tangential direction is called a surface wave. The wavelength of the electromagnetic field in the direction perpendicular to the surface of the dielectric plate is different inside and outside the dielectric, and therefore the wavelength of the combined electromagnetic field is different inside and outside the dielectric. However, when the thickness of the dielectric plate is small, the wavelength of the electromagnetic field inside the dielectric plate and the wavelength of the surface wave are almost equal, and the above ε can be defined as an equivalent material constant in consideration of the thickness of the dielectric plate. That is, the wavelength derived using the equivalent material constant is equal to the wavelength of the surface wave.

Mathematically, the rule for arranging the radiating element that radiates circularly polarized wave is shown in FIG.
The distance r _x between the point a where the radiating element is arranged and the point a is equal to the point a.
Pass through

## EQU15 ## There is a relationship of θ = Arg {H (k r _x )}. The reference point a is located at the center of the surface of the dielectric plate on which the radiating element is arranged, and coincides with the feeding point at the center of the ground conductor on the other surface at the upper and lower positions with the dielectric plate in between.

Due to the nature of the Hankel function, the wavelength of the electromagnetic field slightly changes inside the dielectric plate, but the amount of change is so small that it can be ignored. Therefore, without calculating the Hankel function, the spiral of Archimedes is used. However, it is possible to form a circular polarization pattern.

That is, the distance from the reference point increases by the wavelength of the surface wave each time the circuit makes one round around the reference point.
An Archimedean spiral may be formed, and the radiating element may be arranged on the virtually drawn Archimedean spiral.

In practice, the effect of shortening the wavelength of the surface wave appears due to the coupling between the radiating element and the electromagnetic field inside the dielectric plate. The wavelength shortening rate also increases outside the radiating element with a large amount of coupling. Therefore, when the Archimedean spiral is constructed, it is necessary to reduce the rate of increase in the distance from the reference point. Further, since the radiating element has a radiation impedance, the phase of the radio wave radiated by the radiating element changes. For this reason, in order to radiate a perfect circularly polarized wave, a position rotated by the change in the radiation phase from the position on the spiral of Archimedes about the reference point or the electrical length corresponding to the change in the radiation phase is used as the reference. It is necessary to dispose the radiating element at the position moved in the point direction. As described above, in order to design a better radiation pattern, the change in the coupling amount between the radiating element and the dielectric internal electromagnetic field and the change in the phase of the radiated radio wave are performed with the material constant and the dimension of the dielectric plate as parameters. It is necessary to understand the situation by numerical analysis.

As shown in FIG. 3, when one radiating element is composed of two elongated conductors which are not parallel to each other, the radio waves radiated from the respective elongated conductors are superposed at a distance from the radiating element. , Radio waves of elliptical polarization whose polarization direction rotates with time. Although a general planar antenna has a sharp directivity in the normal direction of the plane, in the planar antenna of the present invention, γ in FIG.
Properly disposing the radiating element by controlling the difference between the angles represented by η and δ and the distances r _x and r _y from the reference point to each elongated conductor and the length of the elongated conductor. Due to
The required elliptical polarization can be obtained, and the directivity of the antenna can be changed. As a result, the planar antenna of the present invention can also receive satellite broadcasts without being attached to an elevation angle while being directly attached to a vertical wall.

In FIG. 4, one radiating element is composed of two elongated conductors having the same length, the extension lines of the central axes of the respective longitudinal axes are orthogonal to each other, and the longitudinal centers of the respective elongated conductors are the same. From the intersections s and t of the axis and the central axis in the minor axis direction, the reference point b
Difference of 1/4 of the wavelength λ of the surface wave of the dielectric plate
And the central axis in the long axis direction of each elongated conductor , The radio waves radiated from these two elongated conductors overlap each other, resulting in perfect circular polarization. Here, similarly to the reference point a, the reference point b is a feeding point on the ground conductor surface of the dielectric plate,
The upper and lower parts are aligned with the dielectric plate in between.

That is, as shown in FIG. 5, since the distance from the reference point is a distance difference of 1/4 of the wavelength at the position of each of the two elongated conductors, power is supplied from the position of the reference point. The propagating electromagnetic field is π / 2 at the position of the two elongated conductors.
Therefore, the radio waves radiated from the two elongated conductors also have a phase difference of π / 2. And,
Since both elongated conductors have different angles in the long axis direction by π / 2 on the dielectric plate surface, the polarization directions of the radiated radio waves also have a spatial phase difference of π / 2. Further, as indicated by an angle α in FIG. 4, when the inclinations of the central axes of the elongated conductors with respect to the reference point direction are equal and the elongated conductors are also equal in length, the electromagnetic field inside the dielectric plate is The amount of coupling with is equal, and the strength of the radio waves emitted from each elongated conductor is equal. Therefore, as shown in FIG. 5, when the radio waves radiated from the two elongated conductors are added in vector, the polarization directions of the combined radio waves are circular polarization waves that rotate with time. Is emitted.

In the planar antenna shown in Japanese Patent Application No. 11-377398, in the case of a circularly polarized radiation pattern, when the instantaneous radiation intensity distribution is observed for each of the horizontal and vertical components with respect to the reference line, the antenna surface The gain is not high because it is not uniform and biased as a whole.

That is, as shown in FIG. 6, as the angle between the extension line of the long-axis center axis of the elongated conductor and the virtual reference line increases, the radio wave emitted by each elongated conductor is increased. The horizontal component parallel to the virtual reference line becomes smaller,
On the contrary, the component perpendicular to the virtual reference line becomes large. Therefore, when we look at circularly polarized waves for both horizontal and vertical components,
The radiation intensity of the vertical component is distributed in a figure 8 shape over the entire antenna surface. On the contrary, the horizontal component is distributed in a figure 8 shape orthogonal to the radiant intensity distribution of the vertical component.

Therefore, as shown in FIG. 7, the directivity of the horizontal component of the circularly polarized radio wave is sharp in the horizontal plane including the virtual reference line, but is not in the vertical plane. Not sharp. On the contrary, the reverse of the directivity of the vertical component of the radio wave occurs, and the directivity of the combined circularly polarized radio wave is not sufficiently sharp. Generally, when radiation is performed with uniform radiation intensity from the entire antenna surface, the directivity becomes sharp and the gain becomes high. That is, in the plane antenna shown in Japanese Patent Application No. 11-377398, in which both horizontal and vertical polarization components are distributed in a figure 8, sharp directivity cannot be obtained and sufficient gain cannot be obtained.

The embodiment of FIG. 8 is a basic radiating element pattern for radiating circularly polarized waves according to the planar antenna of the present invention. Since each radiating element 11 radiates circularly polarized wave, the radio wave For both horizontal and vertical components, the radiation intensity distribution on the antenna surface becomes uniform, and the directivity becomes sharp,
Antenna gain is improved. It is necessary to change the rotating direction of the circularly polarized wave, that is, the rightwardly polarized wave and the leftwardly polarized wave, to change the winding direction of Archimedes's spiral and the inclination direction of the two elongated conductors 11 constituting one radiating element. That is clear.

The embodiment shown in FIG. 9 is an example of a pattern in which one radiating element is constituted by one elongated conductor 14 based on the pattern of the elongated conductor of FIG. Circularly polarized radio waves are radiated as a whole antenna, and by adjusting the length and spacing of the radiating elements, good characteristics can be obtained as in the embodiment of FIG. It is also possible to adopt a pattern in which both the radiating elements of FIGS. 8 and 9 are mixed such that one radiating element is composed of one or two elongated conductors.

In the embodiments of FIGS. 8 and 9, the lengths of the elongated conductors 11 and 14 forming all the radiating elements and the intervals between the adjacent radiating elements are equal, but the individual radiating elements are elongated. By adopting a configuration in which the shaped conductors 11 and 14 have different lengths or a configuration in which the distance between adjacent radiating elements is different, the coupling amount with the electromagnetic field inside the dielectric plates 10 and 13 is adjusted, This is effective in making the radiation intensity distribution in the antenna plane uniform.

In the planar antenna of the present invention, the electromagnetic field introduced into the dielectric propagates through the dielectric plate as a waveguide. This is because an electromagnetic field having a high frequency has a property of being easily propagated in a dielectric material rather than in air, which is similar to how light propagates in an optical fiber.

In the planar antenna of the present invention, no elongated conductor is directly fed, but as shown in FIG. 10, an electromagnetic field inside the dielectric plate (in FIG. 10, an electric field is represented by E, A magnetic field is represented by H) by electromagnetic induction, and a current (i ₁ , i _{2 in} FIG. 10) flows through the elongated conductor, and a radio wave is radiated.

The rule of arranging the circularly polarized wave radiating element of the present invention is based on the same rule as in JP-A-57-87603, but in JP-A-57-87603, the radiating element is formed on a metal plate. They are a pair of inverted V-shaped slots, and the planar antenna of the present invention is different in that they are two elongated conductors on a dielectric plate.

Further, in the flat antenna of Japanese Patent Laid-Open No. 57-87603, an electromagnetic field propagates through a space sandwiched by two metal plates and the slot radiates a radio wave, whereas the flat antenna of the present invention has a flat antenna. , An electromagnetic field propagates inside the dielectric, and a current flowing through an elongated conductor coupled with the electromagnetic field inside the dielectric by electromagnetic induction radiates radio waves.

That is, electromagnetically, it is disclosed in Japanese Patent Laid-Open No. 57-87.
In the planar antenna of No. 603, the space sandwiched by the two metal plates is radiated by the magnetic current of the slot, which is coupled with the electromagnetic field propagating in the TEM mode. This is radiation due to a current flowing in an elongated conductor that is coupled with an electromagnetic field propagating inside the dielectric plate in the wave mode, and the operating mechanism of the antenna is different.

In the pattern for radiating circularly polarized waves in the plane antenna disclosed in Japanese Patent Application No. 11-377398, one radiating element is composed of one elongated conductor, and the central axes of all elongated conductors in the long axis direction. The extension line of is arranged so as to pass through the reference point. On the other hand, in the pattern for radiating the circularly polarized wave of the planar antenna of the present invention, one radiating element is composed of one or two pairs of elongated conductors which are not parallel to each other, and which elongated conductor The extension line of the central axis of the long axis does not pass through the reference point. As a result, Japanese Patent Application No. 11-3
It is possible to obtain a uniform radiation intensity distribution over the entire antenna surface and obtain a higher gain than the plane antenna shown in No. 77398.

FIG. 11 shows rules for arranging a pattern for radiating linearly polarized waves. A radiating element pattern that radiates a linearly polarized wave that is polarized in a direction parallel to the virtual reference line by using a virtual reference line that passes the reference point q and a virtual orthogonal line that passes the point q and is orthogonal to the virtual reference line. To create. At this time, the reference point q is located at the center of the surface of the dielectric plate on which the radiating element is arranged, and coincides with the feeding point at the center of the ground conductor on the other surface at the upper and lower positions with the dielectric plate in between. ing.

The electromagnetic field fed from the feeding point is the reference point q.
Propagating concentrically in the dielectric plate centered around, and its form is represented by the Hankel function. At this time, ζ (0 ≦ ζ ≦ 2π)
, Any constant of

## EQU16 ## Radiating elements on the circumference of which radius is r having a relationship of Arg {H (k r)} = ζ radiate radio waves of the same phase. Since r satisfying the above equation exists infinitely, all of the radiating elements of equal length which are formed in the concentric circle group and arranged on the concentric circle group and arranged in parallel with the virtual reference line are Radio waves with the same phase are radiated.

At this time, in the radiating elements on the same circumference, the directions of the radio waves radiated on the right side and the left side are opposite to each other with the virtual orthogonal line as a boundary, and the phases are spatially different by π radian. As it is, the radio wave from the radiating element on the right side and the radio wave from the radiating element from the left side cancel each other with the virtual orthogonal line as a boundary. In order to avoid this, the radiating element is arranged only on one of the left and right sides with the virtual orthogonal line as a boundary on the same circumference.

If radiating elements that radiate radio waves different by π radians are arranged on the opposite side of the virtual orthogonal line, they will strengthen each other without canceling each other.

Ζ−ξ = π Using the constant ξ (0 ≦ ξ ≦ 2π)

[Equation 18] A radiating element may be arranged on the circumference of a concentric circle group having a radius r ′ satisfying Arg {H (k r ′)} = ξ. At this time, the radiating element is arranged such that the intersection of the central axis of the elongated conductor and the central axis of the short axis of the elongated conductor, which is the radiating element, coincides with the circumference formed by the above equation.

In the design of the actual pattern, for the same reason as using the Armedides spiral for the circularly polarized pattern, a group of concentric circles having a radius of several sequences intersecting half the wavelength of the surface wave is used and the dielectric The radiating elements may be arranged on the left and right of the virtual orthogonal line in the ascending order of radius on the plate. In addition, since the actual electromagnetic field in the dielectric plate has a shortened wavelength due to coupling with the radiating element, the coupling amount between the radiating element and the electromagnetic field inside the dielectric plate should be considered for better pattern design. , It is also the same as when designing a circular polarization pattern that the difference in radius of the concentric circle group needs to be smaller than the half wavelength of the surface wave.

The rule for arranging the linearly polarized wave of the present invention is the same as that for radiating the linearly polarized wave of the plane antenna disclosed in Japanese Patent Application No. 11-377398. However, Japanese Patent Application No. 11
In -377398, the central axis of the long axis direction of all the radiating elements passes through the reference point, whereas in the present invention, all the radiating elements are parallel to the virtual reference line.

FIG. 12 shows the principle of radiating a linearly polarized wave polarized in the virtual reference line direction in Japanese Patent Application No. 11-377398. Since all the radiating elements of the radiating element face the direction of the reference point, the radiated radio wave includes a radio wave component orthogonal to the virtual reference line. The component orthogonal to the polarization direction is canceled by the radio wave emitted from the radiating element located symmetrically with respect to the virtual reference line. That is, in FIG. 12, the component of the radio wave orthogonal to the virtual reference line of the radio wave emitted from the radiating element of B is
The radio waves radiated from the radiating element at the position B ′ cancel out the orthogonal components, leaving only the component parallel to the virtual reference line. For this reason, the supplied radio waves are not effectively radiated, and the efficiency as an antenna is poor.

FIG. 13 shows an example of a pattern for radiating linearly polarized waves according to the present invention. All the radiating elements are arranged parallel to the virtual reference line, and do not radiate a component perpendicular to the virtual reference line. Therefore, there is no loss in the supplied power, and the efficiency of the antenna is high. That is, Japanese Patent Application No. 11-37739
In the pattern of radiating the linearly polarized wave of No. 8, half of the supplied power is canceled out and is not effectively radiated, and the efficiency of the antenna is only 50% at maximum. On the other hand, in the pattern for radiating the linearly polarized wave according to the present invention, the supplied electric power is effectively radiated without canceling each other, so that the antenna can be made highly efficient.

In the embodiment of FIG. 13, all the radiating elements have the same length, but since the coupling with the electromagnetic field inside the dielectric is adjusted, the length adjustment for each radiating element is effective.

The embodiments of FIGS. 14 and 15 are examples for reducing the reflection of an electromagnetic field at the feeding point where the coaxial connector is connected to the dielectric plate 51 and for impedance matching.

In FIG. 14, a joining metal fitting 57 for expanding the outer conductor 54 of the coaxial connector in a tapered shape is used, and a tapered conductor 58 connected to the center conductor 55 of the coaxial connector is used.
Is connected to the circular conductor 56. Here, the circular conductor 56 is not provided for the emission of radio waves, but is used for propagating the electromagnetic field guided inside the dielectric plate 51 in the surface wave mode in the lateral direction of the dielectric plate 51. It serves as a guide. It is also possible to adopt a configuration in which the circular conductor 56 and the metal fitting 57 are not used.

In FIG. 15, impedance matching is achieved by moving up and down a threaded stub 60 connected to the center conductor 55 of the coaxial connector. The stub 60 also serves as a circular conductor.

FIG. 16 shows a modification of the conductor 58 for connecting the central conductor 55 and the circular conductor 56 of the coaxial connector.

FIG. 17 shows a modification of the elongated conductor which constitutes the radiating element according to the present invention.

When a large amount of electric 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.

[0053]

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

Since a uniform radiation intensity distribution can be obtained from the entire antenna surface, the directivity becomes sharp and the antenna gain becomes high.

Since all are integrated with the dielectric and are composed of only planes, they have a plane antenna having a hollow structure, a curved structure like a parabolic antenna, and support the primary radiator at the focal position. It is much more robust and mechanically stronger than the antenna it must have.

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 such as a conventional satellite dish for satellite broadcasting.

When used as a moving body, the volume required for carrying is smaller than that of a conventional parabolic antenna,
Suitable for mobile communication.

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 drawing for explaining the definition of the central axis of the elongated conductor.

FIG. 3 is a diagram illustrating a rule for arranging an elliptically polarized wave pattern.

FIG. 4 is a diagram illustrating a rule for arranging a circular polarization pattern.

5 is a drawing for explaining the principle of circular polarization of the two elongated conductors of FIG.

FIG. 6 is a diagram for explaining that a radio wave radiated by a circular polarization pattern of Japanese Patent Application No. 11-377398 has a biased radiation intensity distribution on the antenna surface.

FIG. 7 is a diagram explaining that in the circular polarization pattern of Japanese Patent Application No. 11-377398, there are differences in the directivity and gain of the horizontal component of the circular polarization between the horizontal plane and the vertical plane.

FIG. 8 shows a pattern for radiating circularly polarized waves according to the present invention,
This is an embodiment in which the radiating element is composed of two elongated conductors.

FIG. 9 shows a pattern of circularly polarized radiation according to the present invention,
It is an example in the case where the radiating element is composed of one elongated conductor.

FIG. 10 is a diagram schematically illustrating how an elongated conductor is coupled with an electromagnetic field inside a dielectric.

FIG. 11 is a drawing for explaining the arrangement rule of the radiating element that radiates a linearly polarized wave according to the present invention.

FIG. 12 is a diagram illustrating that the linear polarization pattern of Japanese Patent Application No. 11-377398 does not increase the antenna efficiency in principle.

FIG. 13 is a diagram illustrating that a highly efficient planar antenna can be realized with the linear polarization pattern of the present invention.

FIG. 14 is an embodiment for achieving impedance matching at the feeding point of the planar antenna according to the present invention.

FIG. 15 is an embodiment for achieving impedance matching at the feeding point of the planar antenna according to the present invention.

FIG. 16 is a modification of the conductor that connects the circular conductor and the central conductor of the coaxial connector for impedance matching at the feeding point of the planar antenna according to the present invention.

FIG. 17 is a modification of the elongated conductor of the planar antenna according to the present invention.

[Explanation of symbols]

1, 10, 13, 51 Dielectric plate 2, 52 Ground conductor 3, 11, 14, 53 Radiating element 4 Coaxial connector 5, 58 Conductor 6, 12, 15, 56 Circular connecting the central conductor and circular conductor of the coaxial connector Conductor 54 Outer conductor 55 of coaxial connector Central conductor 57 of coaxial connector Joint fitting 59 Dielectric 60 stub filling between inner conductor and outer conductor of coaxial connector

Claims (3)

(57) [Claims] 1. A required number of radiating elements are arranged on one surface of a dielectric plate having a low dielectric loss characteristic, a ground conductor is arranged on the other surface of the dielectric plate, and a central portion of the ground conductor. In the case of a planar antenna with a structure that feeds from, each radiating element consists of one or two elongated conductors, and when one radiating element consists of two elongated conductors, either Intersection x of the central axis of the long and short axes of one of the elongated conductors and its plane Using the constant k, which is determined by the frequency of the electromagnetic field and the electromagnetic material constant of the dielectric plate, with the (radian method), the deviation angle of the Hankel function H is expressed as follows: θ = Arg {H ( kr _x )}, the distance r _y between the reference point a and the intersection y of the central axis of the other elongated conductor with the central axis of the major axis and the central axis of the minor axis of the other elongated conductor is Using the wavelength λ, 0 <r _x −r _y <λ / 2 η and the angle δ formed by the extension lines of the central axes of the two elongated conductors are each larger than 0 radian and smaller than π radian, and one radiating element is composed of one elongated conductor. If the radiating element is used, the radiating element is composed of either one of the two elongated conductors having the point x or the point y, and all the radiating elements are not directly fed but the electromagnetic field inside the dielectric plate. A planar antenna characterized by being coupled with electromagnetic induction to radiate radio waves. 2. The extension lines of the central axes of the long conductors of the two elongated conductors constituting one radiating element are orthogonal to each other, and the central axis and the minor axis of the elongated conductors of the two elongated conductors are orthogonal to each other. center Between the following, r _s −r _t = λ / 4 The planar antenna according to claim 1, wherein the angles between them are equal. 3. A required number of radiating elements are arranged on one surface of a dielectric plate having a low dielectric loss characteristic, a ground conductor is arranged on the other surface of the dielectric plate, and a central portion of the ground conductor. A radiating element consisting of a single elongated conductor, and all radiating elements have a reference point q on the surface of the dielectric plate on which the radiating elements are arranged. It is located in line symmetry with respect to the passing virtual reference line, and with the reference point q as the center, radii Ri, Rj (i, j = 1, 2, 3, ... N,
n is a positive integer), using the constant k determined by the frequency of the electromagnetic field and the electromagnetic material constant of the dielectric plate, two constants ζ and ξ in the relationship of ζ−ξ = π Between and, as the argument of the Hankel function H (the radian method), Arg {H (k Ri)} = ζ (0 ≦ ζ ≦
2π) [Equation 6] Arg {H (k Rj)} = ξ (0 ≦ ξ ≦
All radiating elements are arranged on the virtual concentric circle group represented by the relationship 2π), and at the same time, the radiating elements on each virtual concentric circle are virtual orthogonal lines that are orthogonal to the virtual reference line and pass through the reference point q. Is arranged only on one of the two sides, the longitudinal central axes of all radiating elements are parallel to the virtual reference line, and all radiating elements are not directly fed but Coupled by electromagnetic induction with the electromagnetic field inside the body plate,
A flat antenna that emits radio waves.