JP2000183641A - Horizontal in-plane non-directional antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To radiate radio waves into a horizontal surface with uniform polarization without using a higher mode generator or a circular polarization generator by providing many grooves on the reflection surface of a reflecting mirror at intervals being smaller than the wavelengths of the radio, waves, so that the polarization direction of the radio waves reflected by the reflecting mirror can be of desired polarization. SOLUTION: Many grooves are provided on the reflection surfaces of a reflecting mirror at intervals which are being smaller than the wavelengths of radio waves so that the polarization direction of radio waves reflected by the reflecting mirror can be of desired polarization. That is, many grooves which are about 1/4 wavelength in depth and are provided at intervals smaller than the wavelengths are formed on the reflection surface 2 of a main reflecting mirror 1. The direction of polarization made incident on the main reflecting mirror 1 is turned in the direction of desired vertical polarization, in such a manner that the reflection surface of the mirror 1 is formed by the grooves reflection surface 2 in this way. A conical electromagnetic horn 3 is excited by linear polarization of a basic TE11 mode, and radio waves radiated from the horn 3 are reflected against the mirror 1 and radiated uniformly into a horizontal surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an omnidirectional antenna in a horizontal plane used for an antenna for a radio communication base station or the like.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a side view showing a conventional omnidirectional antenna in a horizontal plane disclosed in Japanese Patent Application Laid-Open Publication No. H10-209,878. In the figure, 11 is a conical or frusto-conical rotating curved reflecting mirror, 12 is its reflecting surface, 13 is a conical electromagnetic horn as a primary radiator, 14 is an electromagnetic wave in a required mode with respect to the conical electromagnetic horn 13 Is a mode generator, 15 is a waveguide, and 16 is a transceiver for transmitting and receiving electromagnetic waves.

A desired mode is generated through a mode generator 14 by an electromagnetic wave transmitted from a transceiver 16 via a waveguide 15 to excite a conical electromagnetic horn 13 so that the radio wave is reflected by a conical reflecting surface. It is reflected at 12 and emitted into a horizontal plane.

In the case where the conical electromagnetic horn 13 is used as the primary radiator as described above, when it is desired to obtain a vertically polarized wave, a higher-order mode generator is used as the mode generator 14 so that the transmitter / receiver 16 transmits the signal. The emitted TE ₁₁ mode (basic mode) is converted into a TM ₀₁ mode higher mode to excite the conical horn 3.

When it is desired to obtain horizontal polarization, another type of mode generator 14 is used as the mode generator 14.
The TE ₁₁ mode is converted to a higher order mode of the TE ₀₁ mode to excite the conical electromagnetic horn 13.

On the other hand, when it is desired to obtain a circularly polarized wave, the conical electromagnetic horn 13 may be excited in the TE ₁₁ mode. In that case, however, a separate circularly polarized wave generator is required.

[0007]

In the omnidirectional antenna in the horizontal plane having such a configuration, the conical electromagnetic horn 1 is used.
Higher-order mode generator 14 for exciting 3 in higher-order mode
Was needed. Alternatively, when it is desired to obtain circularly polarized waves, a circularly polarized wave generator is required.

An object of the present invention is to provide an omnidirectional antenna in a horizontal plane capable of radiating radio waves with a uniform polarization in a horizontal plane without using a higher-order mode generator or a circularly polarized wave generator. With the goal.

[0009]

An omnidirectional antenna in a horizontal plane according to the present invention includes a reflector having a generally conical or truncated cone shape, and a radiation port provided on the reflector at a central axis of the cone or truncated cone shape. In a horizontal omnidirectional antenna composed of a primary radiator and a primary radiator arranged so that the direction of polarization of radio waves reflected by the reflector is the desired polarization, A number of grooves were provided at intervals smaller than the wavelength of the radio wave.

Also, a main reflector having a substantially conical or truncated cone shape, a sub-reflector having a substantially hemispherical shape and having a central axis coinciding with the central axis, and disposed opposite to each other; In a horizontal omnidirectional antenna composed of a primary radiator arranged so that the radiation port faces the sub-reflector, the direction of polarization of radio waves reflected by the main reflector and the sub-reflector is changed to a desired polarization. A large number of grooves are provided on one of the reflecting surface of the main reflecting mirror and the reflecting surface of the sub-reflecting mirror at intervals smaller than the wavelength of the radio wave so as to form waves.

[0011] Further, the large number of grooves are formed at a first divided portion which is approximately 0 ° clockwise with respect to the polarization direction of the radio wave incident on the reflecting surface when the reflecting surface is divided into four in the circumferential direction. In the second divided portion which is approximately 90 ° clockwise so as to be substantially the same direction as the polarization direction, the clock is so formed as to be approximately 45 ° clockwise with respect to the polarization direction. In the third divided portion, which is approximately 180 ° around, in the fourth divided portion, which is approximately 270 ° clockwise, so as to be in a direction orthogonal to the polarization direction,
The grooves formed in each of the divided portions are formed so as to be approximately 135 ° clockwise with respect to the polarization direction, and to be smoothly continuous.

[0012] The multiple grooves are formed at regular intervals so as to be approximately 45 ° clockwise with respect to the polarization direction of the radio wave incident on the reflection surface.

The depth of the groove is approximately 概 wavelength of the radio wave.

The depth of the groove is approximately 1/8 wavelength of the radio wave.

The omnidirectional antenna in a horizontal plane according to the present invention includes a reflector having a generally conical or truncated cone shape,
On the central axis of the cone or truncated cone, a primary radiator arranged with the radiation port facing the reflector, and provided on the outer periphery of the reflector so that the radio wave reflected by the reflector is transmitted In a horizontal omnidirectional antenna composed of a radome and a radome, a polarization direction rotation function unit is provided on the radome.

The polarization direction rotation function section is a meander line.

The omnidirectional antenna in a horizontal plane according to the present invention includes a reflector having a substantially conical or truncated cone shape,
On the central axis of the cone or truncated cone, a primary radiator arranged with the radiation port facing the reflector, and provided on the outer periphery of the reflector so that the radio wave reflected by the reflector is transmitted In the omnidirectional antenna in a horizontal plane composed of a radome and a radome, a circularly polarized wave generation function unit is provided on the radome.

Further, the circularly polarized wave generation function section is a meander line.

Further, the omnidirectional antenna in a horizontal plane according to the present invention comprises a reflector having a substantially conical or frustoconical shape, and a primary radiator arranged on a conical or frustoconical central axis. In a horizontal omnidirectional antenna, the primary radiator is a coaxial horn.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a side view of a main part of an omnidirectional antenna in a horizontal plane according to the present invention. FIG. 2 is a bottom view of FIG. 1 showing the groove shape of the main reflector viewed from the conical electromagnetic horn side. In the figure, 1 is a main reflecting mirror which is a conical or frusto-conical rotating curved reflecting mirror,
Reference numeral 2 denotes a reflecting surface, and reference numeral 3 denotes a conical electromagnetic horn used as a primary radiator.

The reflecting surface 2 of the main reflecting mirror 1 has a depth of about 1
/ 4 wavelength, and a large number of grooves provided at intervals smaller than the wavelength are formed. In the present embodiment, the conical electromagnetic horn 3 is excited by linearly polarized waves in the basic TE ₁₁ mode (in FIG. 1, the direction of polarization perpendicular to the paper surface).

The radio wave radiated from the conical electromagnetic horn 3 is reflected by the main reflecting mirror 1 and radiated uniformly in a horizontal plane. At this time, if the reflecting surface of the main reflecting mirror 1 is constituted by a conventional surface having no groove, the polarization direction differs depending on the observation direction. In the present embodiment, the direction of polarization incident on the main reflecting mirror 1 is rotated in a desired direction of vertical polarization by forming the reflecting surface of the main reflecting mirror 1 with the grooved reflecting surface 2.

FIG. 3 shows the function of rotating the polarization direction of the grooved reflecting surface 2.
This will be described with reference to FIG. FIG. 3 is an enlarged view showing a part of the surface of the grooved reflection surface 2. FIG. 4 is a sectional view taken along the line AA ′ of FIG. As shown in FIGS. 3 and 4, grooves having a depth of １ ／ wavelength are provided on the surface of the grooved reflection surface 2 at intervals smaller than the wavelength. Then, as shown in the figure, consider a case where a radio wave having a polarization direction of an angle α enters the grooved reflection surface 2 at an angle β.

Of the incoming radio wave E, a component Ep in the polarization direction parallel to the groove is reflected on the upper surface of the groove, and a component Ev in the polarization direction orthogonal to the groove is reflected on the lower surface of the groove. At this time, since the depth of the groove is １ ／ wavelength, the phase of Ev is delayed by 180 degrees compared to Ep due to reflection, and Ev ′ = − Ev. Therefore, the reflected radio wave becomes E ', and the polarization is rotated. The angle γ of the polarization direction of E ′ is given by the following equation.

Γ = β− (α−β) = 2β−α (1)

In this embodiment, since the polarization direction α of the radio wave incident from the conical electromagnetic horn 3 to each point on the main reflecting mirror 1 and the desired polarization direction γ after reflection are known, By providing grooves each having a quarter wavelength and having the angle β given in (1) at each corresponding point on the main reflecting mirror 1, the polarization can be rotated in a desired vertical polarization direction.

Returning to FIG. 2, the direction of the grooves on the grooved reflection surface 2 will be specifically described. For example, a conical electromagnetic horn 3
Is divided into upper part, lower part, right part and left part in FIG.

In the upper part, the polarization direction α of the radio wave E radiated from the conical electromagnetic horn 3 is α = 90 ° with respect to the horizontal in FIG. On the other hand, since the polarization direction γ of the radio wave E ′ after being reflected by the grooved reflecting surface 2 needs to be γ = 90 °, the direction β of the groove is β = (α−γ ) / 2 = 90 °.

Next, in the lower part, the polarization direction α of the radio wave E radiated from the conical electromagnetic horn 3 is α = 90 °. On the other hand, since the polarization direction γ of the radio wave E ′ after being reflected by the grooved reflecting surface 2 needs to be γ = −90 °, the direction β of the groove is β = (α−γ) / 2 = 0 °.

Next, regarding the right part, the polarization direction α of the radio wave E radiated from the conical electromagnetic horn 3 is α = 90 °. On the other hand, since the polarization direction γ of the radio wave E ′ after being reflected by the grooved reflection surface 2 needs to be γ = 0 °, the direction β of the groove is β = (α−10γ) / 2 = 45. °.

Finally, regarding the left part, the polarization direction α of the radio wave E radiated from the conical electromagnetic horn 3 is α = 90 °
Becomes Since the polarization direction γ of the radio wave E ′ after being reflected by the grooved reflection surface 2 needs to be γ = 180 °, the groove direction β is β = (α−γ) / 2 = 135 °. Become. Then, when the directions of the grooves of the above-described portions are connected continuously, the shape as shown in FIG. 2 is obtained.

In the present embodiment, the case where the radio wave radiated from the antenna is vertically polarized has been described, but it goes without saying that the same applies to the case of horizontal polarized wave.

Further, as described above, the grooved reflecting surface 2 has been described assuming that the groove is formed by cutting a groove having a depth of 1/4 wavelength in a metal. For example, as shown in FIG. Alternatively, a grid may be formed by etching or the like on one side of the metal plate 9 using a dielectric substrate 10 having a thickness of 1/4 wavelength and a metal plate 9 attached to both surfaces.

Embodiment 2 FIG. 6 is a side view of a main part showing another example of the omnidirectional antenna in a horizontal plane according to the present invention.
FIG. 7 is a top view of the main reflecting mirror of FIG. 6 showing the groove shape of the main reflecting mirror as viewed from the sub-reflecting mirror side. In the figure, 21 is a main reflecting mirror which is a conical or frusto-conical rotating curved reflecting mirror, and 22 is its reflecting surface. On the reflecting surface 22, a groove substantially similar to that of the first embodiment is formed. Reference numeral 4 denotes a sub-reflection mirror which is a rotating curved reflection mirror provided to face the main reflection mirror 21. In the present embodiment, the conical electromagnetic horn 3 is provided at the center of the main reflecting mirror 21 toward the sub-reflecting mirror 4.

The radio wave radiated from the conical electromagnetic horn 3 is reflected by the sub-reflecting mirror 4, further reflected by the main reflecting mirror 1, and radiated uniformly in a horizontal plane. In addition to obtaining the same effects as in the first embodiment, in the present embodiment, a two-mirror configuration of the main reflecting mirror 21 and the sub-reflecting mirror 4 is used.
There is an advantage that the degree of freedom of the mirror surface configuration is increased.

Although the present embodiment has been described with reference to the case where the mirror is constituted by two mirrors, it is needless to say that the same construction can be realized by using three or more mirror surfaces.

Embodiment 3 FIG. 8 is a side view of a main part showing another example of the omnidirectional antenna in a horizontal plane according to the present invention.
FIG. 9 is a bottom view of the sub-reflection mirror of FIG. 8 showing the groove shape of the sub-reflection mirror as viewed from the main reflection mirror side. In the figure, reference numeral 31 denotes a main reflecting mirror that is a conical or truncated conical rotating curved reflecting mirror. Unlike the first embodiment, the main reflecting mirror 31 has no groove formed on the surface. Reference numeral 24 denotes a sub-reflection mirror which is a rotating curved reflection mirror provided to face the main reflection mirror 31.
A groove shown in FIG. 9 is formed on the reflection surface 25 of the sub-reflector 24 so as to obtain the same effect as in the first or second embodiment. The conical electromagnetic horn 3 is provided at the center of the main reflecting mirror 31 toward the sub-reflecting mirror 24.

The radio wave radiated from the conical electromagnetic horn 3 is reflected by the sub-reflecting mirror 24, further reflected by the main reflecting mirror 31, and radiated uniformly in a horizontal plane. In addition to obtaining the same effects as the first and second embodiments, in the present embodiment, the reflecting surface of the main reflecting mirror 31 is a normal non-grooved surface, and the reflecting surface of the sub-reflecting mirror 24 is grooved. As the reflection surface 25,
The direction of polarization is rotating. That is, in the present embodiment, the grooved reflecting surface 25 may be formed not on the large main reflecting mirror 31 but on the small sub-reflecting mirror 24, so that processing becomes easy.

Although the present embodiment has been described with a case where the mirror is constituted by two mirrors, it is needless to say that the same construction can be achieved by using three or more mirror surfaces. It goes without saying that a grooved reflecting surface can be formed on any of the mirror surfaces constituting the antenna.

Embodiment 4 FIG. FIG. 10 is a side view of a main part showing another example of the in-horizontal omnidirectional antenna of the present invention. FIG. 11 is a bottom view of FIG. 10 showing the groove shape of the main reflecting mirror as viewed from the conical electromagnetic horn side. In the figure,
41 is a main reflecting mirror which is a rotating curved reflecting mirror having a conical or frusto-conical shape, 42 is a reflecting surface and a grooved reflecting surface 42 having a depth of approximately 1/8 wavelength, which is smaller than the wavelength. A large number of provided grooves are formed. 3 is a conical electromagnetic horn used as a primary radiator.

The conical electromagnetic horn 3 is the same as that shown in FIG. 1 and performs the same function. The conical electromagnetic horn 3 is excited by linearly polarized light in the basic TE ₁₁ mode (in FIG. 10, the direction of polarization perpendicular to the plane of the drawing).

The radio wave radiated from the conical electromagnetic horn 3 is reflected by the main reflecting mirror 41 and is radiated uniformly in a horizontal plane. At this time, the reflecting surface of the main reflecting mirror 41 is set to have a specific direction corresponding to the polarization direction of the linearly polarized light incident on each reflection point and a depth of approximately 1/8 wavelength, which is smaller than the wavelength. The linearly polarized wave can be converted into a circularly polarized wave by using the grooved reflecting surface 2 composed of a large number of grooves provided in the above.

A circularly polarized wave generating function of generating circularly polarized waves from linearly polarized waves of the grooved reflecting surface 42 will be described with reference to FIGS. FIG. 12 is an enlarged view showing a part of the surface of the grooved reflection surface 42. FIG. 13 is a sectional view taken along line BB ′ of FIG.
It is arrow sectional drawing along a line. The grooved reflecting surface 2 is shown in FIG.
As shown in (1), grooves having a depth of 1/8 wavelength are provided at intervals smaller than the wavelength. Now, as shown in FIG. 12, consider a case where the radio wave E incident on the grooved reflection surface 42 forms an angle of 45 ° with the groove. At this time, a component Ep in a polarization direction parallel to the groove and a component E in a polarization direction orthogonal to the groove are provided.
v has the same absolute value. Ep is reflected on the upper surface of the groove, and Ev is reflected on the lower surface of the groove. At this time, since the depth of the groove is １ ／ wavelength, the phase of Ev is delayed by 90 degrees as compared with Ep due to reflection. Therefore, the reflected wave is a combination of orthogonal radio waves having the same absolute value and different phases by 90 °, and a circularly polarized wave is obtained.

Returning to FIG. 11, the direction of the grooves on the grooved reflection surface 42 will be specifically described. The polarization direction of the radio wave E radiated from the conical electromagnetic horn 3 is substantially the same in all of the upper, lower, right and left portions, and the polarization direction α of the radio wave E is 90 °.
Becomes Strictly speaking, TE ₁₁ is formed by the conical electromagnetic horn 3.
Since it is excited in the mode, the polarization direction α of the radio wave E is α = '90 ° on the E plane and the H plane passing through the beam axis of the horn, and on other planes, the divergence is the same as the electric field distribution of the TE ₁₁ mode. . On the other hand, in order for the polarization after being reflected by the grooved reflection surface 2 to be circularly polarized, as shown in FIG. It must be inclined at 45 ° to the direction. Therefore, the extending direction of the groove in each part is substantially the same, and the groove shape is substantially as shown in FIG.

The grooved reflection surface 42 has been described assuming that it is formed by cutting a groove in a metal. However, as shown in FIG. 5, for example, as shown in FIG. Using a dielectric substrate 10 having a thickness of ４ wavelength, a grid may be formed on the metal plate 9 on one side by etching or the like. Further, although the configuration using one reflecting mirror has been described, it goes without saying that the same configuration can be achieved by using two or more mirror surfaces. It goes without saying that a grooved reflecting surface can be formed on any of the mirror surfaces constituting the antenna.

Embodiment 5 FIG. FIG. 14 is a side view of a main part showing another example of the omnidirectional antenna in the horizontal plane according to the present invention. In the figure, a main reflecting mirror 1 and a conical electromagnetic horn 3
Are the same as those shown in FIG. 1 and perform the same function. 5 is a radome. The conical electromagnetic horn 3 is excited by linearly polarized light in the basic TE ₁₁ mode (in FIG. 14, a polarization direction perpendicular to the plane of the drawing). The radome 5 has a function of rotating the polarization direction of the transmitted radio wave.

Radio waves emitted from the conical horn 3 are reflected by the main reflecting mirror 1. At this time, the direction of polarization of the reflected radio wave differs depending on the traveling direction of the radio wave. In this embodiment, by using a radome 5 having a function of rotating the polarization direction by transmitting a radio wave, the polarization direction of the reflected radio wave is rotated to a desired vertical polarization direction.

As an example of the radome 5 having the function of rotating the polarization direction by transmitting radio waves, the function of rotating the polarization direction of the meander line will be described with reference to FIG.
As shown in FIG. 15, the meander line is formed by forming a crank-shaped metal smaller than the wavelength on a sheet such as a dielectric material that transmits radio waves. Of the radio wave E incident on the meander line, the component Ep in the polarization direction parallel to the crank as shown in the figure is inductive, so that the phase is advanced when the meander line is transmitted. On the other hand, for the component Ev in the polarization direction orthogonal to the crank, the meander line becomes capacitive, so that the phase is delayed when transmitting. Therefore, if the meander line is designed so that the phase of Ev is relatively delayed by 180 degrees from Ep after transmission through the meander line, the component in the orthogonal polarization direction after transmission is Ev ′ = − Ev ′. . Therefore, the transmitted radio wave becomes E ', and the polarization direction rotates. At this time, the angle γ of the polarization direction of E is given by the following equation.

Γ = β− (α−β) = 2β−α (2)

In FIG. 14, the polarization direction α of the radio wave radiated from the conical horn 3 and reflected by the main reflecting mirror 1 and then incident on each point on the radome 5 and the desired polarization direction γ after transmission are known. Therefore, by providing a crank-shaped metal having an angle β given by the equation (2) at each corresponding point on the radome 5, the polarization can be rotated in a desired vertical polarization direction.

Ep and Ev in the meander line layer are 18
If a phase difference of 0 degree cannot be provided, a phase difference of 180 degrees can be realized by forming a multilayer structure.

Although the case where the radio wave radiated from the antenna is vertically polarized has been described here, it goes without saying that the same applies to the case of horizontally polarized wave. Also, Ep and Ev
It is needless to say that a circular polarization can be obtained if the absolute values of are equal and the phase difference is 90 degrees. In addition, although the case where a single mirror is used is shown here, it goes without saying that the mirror surface can be similarly configured using two or more mirror surfaces. Further, it goes without saying that a similar configuration can be obtained by using a radome having a polarization direction rotating function having similar properties other than the meander line.

Embodiment 6 FIG. FIG. 16 is a side view of a main part showing another example of the omnidirectional antenna in a horizontal plane according to the present invention. In the figure, the main reflecting mirror 1 is the same as that shown in FIG. 1 and performs the same function. 6 is a coaxial horn and 7 is a coaxial connector.

In this embodiment, a coaxial horn 6 is used as a primary radiator. Coaxial horn 6 emits radio waves having the same polarization direction to the case of excitation of the conical horn TM ₀₁ mode. Further, since excitation can be performed in a normal coaxial mode, power can be supplied directly from the coaxial connector 7, for example, without the need for a mode generator. Therefore, a vertically polarized radio wave can be uniformly radiated in a horizontal plane without using a mode generator.

Although FIG. 16 shows the case where power is supplied by the coaxial connector 7, power can be supplied directly from a circuit board such as a transceiver that transmits radio waves in the coaxial mode.

[0056]

The omnidirectional antenna in a horizontal plane according to the present invention is provided with a reflector having a generally conical or truncated cone shape, and a radiation port facing the reflector on a central axis of the cone or truncated cone. In the horizontal omnidirectional antenna composed of the primary radiator and the radiator, the direction of polarization of the radio wave reflected by the reflector is adjusted to the desired polarization on the reflection surface of the reflector. A number of grooves were provided at smaller intervals. Therefore, without using a higher-order mode generator,
The direction of the polarized light incident on the main reflecting mirror can be rotated in a desired direction, and the radio wave can be radiated in the horizontal plane with a uniform polarized wave.

Also, a main reflector having a substantially conical or truncated cone shape, a sub-reflector having a substantially hemispherical shape and having a central axis coinciding with the main reflector, and disposed opposite to each other; In a horizontal omnidirectional antenna composed of a primary radiator arranged so that the radiation port faces the sub-reflector, the direction of polarization of radio waves reflected by the main reflector and the sub-reflector is changed to a desired polarization. A large number of grooves are provided on one of the reflecting surface of the main reflecting mirror and the reflecting surface of the sub-reflecting mirror at intervals smaller than the wavelength of the radio wave so as to form waves. Therefore, radio waves can be radiated in a horizontal plane with a uniform polarization without using a higher-order mode generator, and the degree of freedom of a mirror surface configuration is increased, and processing is facilitated.

In addition, when the reflecting surface is divided into four parts in the circumferential direction, a large number of grooves are formed at the first divided part which is approximately 0 ° clockwise with respect to the polarization direction of the radio wave incident on the reflecting surface. In the second divided portion which is approximately 90 ° clockwise so as to be substantially the same direction as the polarization direction, the clock is so formed as to be approximately 45 ° clockwise with respect to the polarization direction. In the third divided portion, which is approximately 180 ° around, in the fourth divided portion, which is approximately 270 ° clockwise, so as to be in a direction orthogonal to the polarization direction,
The grooves formed in each of the divided portions are formed so as to be approximately 135 ° clockwise with respect to the polarization direction, and to be smoothly continuous. Therefore, the direction of polarization incident on the reflection surface can be rotated in the direction of desired vertical polarization, and radio waves can be radiated in the horizontal plane with uniform polarization.

The multiple grooves are formed at regular intervals so as to be approximately 45 ° clockwise with respect to the polarization direction of the radio wave incident on the reflection surface. Therefore, the radio wave incident on the reflection surface can be converted into a circularly polarized wave, and the radio wave can be radiated with a uniform polarization in a horizontal plane.

The depth of the groove is approximately １ ／ wavelength of the radio wave. Therefore, the direction of the polarized light incident on the main reflecting mirror can be rotated in the direction of the desired vertically polarized wave.

The depth of the groove is approximately 1/8 wavelength of the radio wave. For this reason, the polarization incident on the main reflecting mirror can be circularly polarized.

The omnidirectional antenna in a horizontal plane according to the present invention includes a reflector having a generally conical or truncated cone shape,
On the central axis of the cone or truncated cone, a primary radiator arranged with the radiation port facing the reflector, and provided on the outer periphery of the reflector so that the radio wave reflected by the reflector is transmitted In a horizontal omnidirectional antenna composed of a radome and a radome, a polarization direction rotation function unit is provided on the radome. Therefore, the direction of the polarized light incident on the main reflecting mirror can be rotated in a desired direction without using a higher-order mode generator.

The polarization direction rotation function section is a meander line. Therefore, fabrication is easy.

The omnidirectional antenna in a horizontal plane according to the present invention includes a reflector having a substantially conical or truncated cone shape,
On the central axis of the cone or truncated cone, a primary radiator arranged with the radiation port facing the reflector, and provided on the outer periphery of the reflector so that the radio wave reflected by the reflector is transmitted In the omnidirectional antenna in a horizontal plane composed of a radome and a radome, a circularly polarized wave generation function unit is provided on the radome. Therefore, the polarization incident on the main reflecting mirror can be converted into circular polarization without using a circular polarization generator.

The circularly polarized wave generation function section is a meander line. Therefore, fabrication is easy.

Further, the primary radiator is a coaxial horn. Therefore, power can be supplied directly from a circuit board such as a transceiver that transmits radio waves in the coaxial mode.

[Brief description of the drawings]

FIG. 1 is a side view of a main part of an omnidirectional antenna in a horizontal plane according to the present invention.

FIG. 2 is a bottom view of FIG. 1 showing the groove shape of the main reflecting mirror as viewed from a conical electromagnetic horn side.

FIG. 3 is an enlarged view showing a part of a surface of a grooved reflection surface.

FIG. 4 is a sectional view taken along the line A-A ′ in FIG. 3;

FIG. 5 is a cross-sectional view showing another configuration example of the grooved reflection surface.

FIG. 6 is a side view of a main part showing another example of the omnidirectional antenna in a horizontal plane according to the present invention.

FIG. 7 is a top view of the main reflecting mirror of FIG. 6 showing the groove shape of the main reflecting mirror as viewed from the sub-reflecting mirror side.

FIG. 8 is a side view of a main part showing another example of the in-horizontal omnidirectional antenna of the present invention.

FIG. 9 is a bottom view of the sub-reflector of FIG. 8 showing the groove shape of the sub-reflector when viewed from the main reflector side.

FIG. 10 is a side view of a main part showing another example of the in-horizontal omnidirectional antenna of the present invention.

FIG. 11 is a bottom view of FIG. 10 showing the groove shape of the main reflecting mirror as viewed from the conical electromagnetic horn side.

FIG. 12 is an enlarged view of a part of the surface of the grooved reflection surface.

FIG. 13 is a sectional view taken along the line BB ′ of FIG. 12;

FIG. 14 is a side view of a main part showing another example of the in-horizontal omnidirectional antenna of the present invention.

FIG. 15 is a diagram for explaining a polarization direction rotation function of a meander line.

FIG. 16 is a side view of a main part showing another example of the omnidirectional antenna in a horizontal plane according to the present invention.

FIG. 17 is a side view showing a conventional omnidirectional antenna in a horizontal plane.

[Explanation of symbols]

1,21,31,41 Main reflector (reflector), 3 conical electromagnetic horn (primary radiator), 4,24 Secondary reflector, 5
Radome, 6 coaxial horn.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shuji Urasaki 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term in Mitsubishi Electric Corporation (reference) 5J020 AA03 BA09 BA18 BC06 DA03 DA04 DA07

Claims (11)

[Claims] 1. A reflector having a substantially conical or truncated cone shape, and a primary radiator disposed on a central axis of the cone or truncated cone with a radiation port facing the reflector. In a horizontal omnidirectional antenna, a large number of radio waves are reflected on the reflecting surface of the reflecting mirror at intervals smaller than the wavelength of the radio wave so that the direction of polarization of the radio wave reflected by the reflecting mirror becomes a desired polarization. An omnidirectional antenna in a horizontal plane characterized by having grooves. 2. A main reflector having a substantially conical or truncated cone shape, a sub-reflector having a substantially hemispherical shape, and disposed so as to be opposed to the main reflector in alignment with the central axis thereof; In the omnidirectional antenna in a horizontal plane, which is composed of a primary radiator disposed with the radiation port facing the sub-reflector, the direction of polarization of radio waves reflected by the main reflector and the sub-reflector A large number of grooves are provided on one of the reflecting surface of the main reflecting mirror and the reflecting surface of the sub-reflecting mirror at intervals smaller than the wavelength of the radio wave so that a desired polarization is obtained. Omnidirectional antenna in the horizontal plane. 3. The first groove, wherein when the reflecting surface is divided into four parts in the circumferential direction, the number of grooves is approximately 0 ° clockwise with respect to a polarization direction of a radio wave incident on the reflecting surface. In the divided portion, the light beam is rotated approximately 90 degrees clockwise so as to be substantially the same as the polarization direction.
In the second divided portion which is approximately 180 ° clockwise with respect to the polarization direction, the third divided portion which is approximately 180 ° clockwise with respect to the polarization direction. In the fourth divided portion, which is approximately 270 ° clockwise so as to be a direction orthogonal to the direction, the direction is approximately 135 ° clockwise with respect to the polarization direction. 2. The groove formed in each divided portion is formed so as to be smoothly continuous.
Or the omnidirectional antenna in the horizontal plane according to 2. 4. The plurality of grooves are formed at regular intervals so as to be approximately 45 ° clockwise with respect to the polarization direction of a radio wave incident on the reflection surface. Item 3. An omnidirectional antenna in a horizontal plane according to item 1 or 2. 5. The omnidirectional antenna in a horizontal plane according to claim 3, wherein the depth of the groove is approximately １ ／ wavelength of a radio wave. 6. The omnidirectional antenna in a horizontal plane according to claim 4, wherein the depth of the groove is approximately ８ wavelength of a radio wave. 7. A reflector having a generally conical or frusto-conical shape, a primary radiator disposed on a central axis of the conical or frusto-conical shape with a radiation port facing the reflector, and the reflector In a horizontal omnidirectional antenna composed of a radome provided on an outer peripheral portion of the reflecting mirror so that radio waves reflected by the mirror are transmitted, a polarization direction rotating function unit is provided on the radome. Characteristic omnidirectional antenna in horizontal plane. 8. The omnidirectional antenna in a horizontal plane according to claim 7, wherein said polarization direction rotation function section is a meander line. 9. A reflector having a generally conical or truncated cone shape, a primary radiator disposed on a central axis of the cone or truncated cone with a radiation port facing the reflector, An omnidirectional antenna in a horizontal plane composed of a radome provided on the outer periphery of the reflector so that radio waves reflected by the mirror can be transmitted, wherein the radome is provided with a circularly polarized wave generation function unit. Characteristic omnidirectional antenna in horizontal plane. 10. The omnidirectional antenna in a horizontal plane according to claim 9, wherein said circularly polarized wave generation function section is a meander line. 11. An omnidirectional antenna in a horizontal plane, comprising a reflector having a generally conical or truncated cone shape and a primary radiator disposed on a central axis of the conical or truncated cone shape. An omnidirectional antenna in a horizontal plane, wherein the primary radiator is a coaxial horn.