JP2022175738A - lens antenna - Google Patents

Abstract

To provide a lens antenna capable of reducing variation in directivity characteristic against frequency change.SOLUTION: A lens antenna 11 of the disclosure includes: a wave guide part 111 extended to a first direction X1, having a first waveguide with a first cylindrical shape formed with a conductor, for transmitting a high frequency signal in the first waveguide; a horn antenna part 112 connected to an output end 111p at which the high frequency signal of the waveguide part 111 outputs, having a second waveguide extended to the first direction X1, with a second cylindrical shape formed with conductor, the aperture area becomes larger toward the first direction X1; a lens base part 113 covering an aperture part 112m at an output end 112p for outputting a high frequency signal of the horn antenna part 112, having a first surface 113s1 perpendicular to the first direction X1, and formed with a dielectric; and a plurality of corrugate parts 114 extending from the first surface 113s1 to the first direction X1, having an approximately cylindrical shape viewing from the first direction X1.SELECTED DRAWING: Figure 1

Description

Applied for application of Article 30, Paragraph 2 of the Patent Act Announced at "ISAP2020" held on January 28, 2021

TECHNICAL FIELD The present disclosure relates to a unidirectional lens antenna for use in a wide frequency band, and more particularly to a lens antenna capable of reducing variations in directivity characteristics with frequency changes.

A quad ridge horn antenna and a double ridge horn antenna are widely known as unidirectional antennas that can be used in a wide frequency band. For example, FIG. 1 of Non-Patent Document 1 describes a quad-ridge horn antenna that can be used for vertical polarization and horizontal polarization. A quad-ridge horn antenna has wideband and unidirectional directivity characteristics (radiation directivity), but has the characteristic that the beam becomes sharper and narrower as the frequency increases. 12 and 13 of Non-Patent Document 1 describe that the higher the frequency, the smaller the value of the -3 dB beam width and the narrower the beam. Specifically, in FIG. 13A of Non-Patent Document 1, the -3 dB beam width is about 100 degrees when the frequency is 6 GHz (gigahertz), and the -3 dB beam width is about 100 degrees when the frequency is 9 GHz. It is stated to be about 70 degrees. That is, at approximately 10 degrees per GHz, the minus 3 dB beamwidth tapers off. In addition, the directivity characteristic is sometimes referred to as radiation pattern characteristic.

The double ridge horn antenna is a horn antenna for single polarized wave in which the ridge for polarization on either the vertical plane or the horizontal plane of the quad ridge horn antenna is removed. A double ridge horn antenna is described in Fig. 3 of Non-Patent Document 2, for example. These double ridge horn antennas and quad ridge horn antennas have a wide band, but have the characteristic that the beam width becomes smaller as the frequency increases. Fig. 2 of Non-Patent Document 2 also describes a quad ridge horn antenna.

It is generally known that the higher the frequency, the smaller the beam width of a unidirectional antenna. The reason why the beam width becomes smaller as the frequency becomes higher is as follows.

For an antenna having a certain physical aperture area, the gain of that antenna is a value corresponding to the wavelength. For example, consider an antenna with an aperture diameter of length (N×λ1). However, N is a natural number and λ1 is the wavelength. Here, when the frequency is doubled, the wavelength is halved, so λ1 becomes 0.5λ1. Therefore, in this case, the aperture diameter of the antenna is doubled because the unit is (0.5λ1). As the aperture diameter increases, the gain of the antenna increases and the beam width decreases.

Patent Document 1 describes a lens antenna that combines a convex lens and a conical horn. The lens antenna described in Patent Document 1 has the effect of improving the matching characteristics of the antenna, but the beam width becomes smaller as the frequency increases.

Paragraph 0037 and FIGS. 1 and 7 of Patent Document 2 describe a radiator as a structure of a horn, Paragraph 0039 describes a lens antenna, Paragraph 0059 and FIG. 8 describe a phase compensation type Fresnel lens is described.

None of Non-Patent Literature 1, Non-Patent Literature 2, Patent Literature 1, and Patent Literature 2 describes a lens antenna capable of reducing variations in directivity characteristics with frequency changes.

Transactions of the Institute of Electronics, Information and Communication Engineers (B) March 2014 Vol. J97-B No. 3 pp324-332 IEEE Paper “Performance Evaluation of Quad-Ridged Horn Antenna in Variation of Its Ridge Profile” (TENCON 2019 - 2019 IEEE Region 10 Conference) JP-A-9-321533 JP-A-2002-237717

As described above, none of Non-Patent Literature 1, Non-Patent Literature 2, Patent Literature 1, and Patent Literature 2 describes a lens antenna capable of reducing variations in directional characteristics with respect to frequency changes. Such an antenna has been desired.

An object of the present disclosure is to provide a lens antenna that solves the above problems.

A lens antenna according to the present disclosure includes:
a waveguide section extending in a first direction and having a first cylindrical waveguide formed of a conductor, wherein a high-frequency signal is transmitted through the first waveguide;
A second cylindrical shape that is connected to the output end of the waveguide section from which the high-frequency signal is output, extends in the first direction, is formed of a conductor, and has an opening area that increases toward the first direction. a horn antenna section having a second waveguide of
a lens base portion covering an opening at an output end of the horn antenna portion for outputting the high-frequency signal, having a first surface perpendicular to the first direction, and formed of a dielectric;
a plurality of corrugated portions extending from the first surface in the first direction, having a substantially cylindrical shape when viewed from the first direction, and formed of a dielectric;
Prepare.

A lens antenna according to the present disclosure includes:
a waveguide section extending in a first direction and having a first cylindrical waveguide formed of a conductor, wherein a high-frequency signal is transmitted through the first waveguide;
A second cylindrical shape that is connected to the output end of the waveguide section from which the high-frequency signal is output, extends in the first direction, is formed of a conductor, and has an opening area that increases toward the first direction. a horn antenna section having a second waveguide of
Covering the opening at the output end of the horn antenna section for outputting the high frequency signal, having a first surface perpendicular to the first direction and a second surface on the opposite side to the first surface, and made of a dielectric material a formed lens base;
a plurality of other corrugated portions extending from the second surface in a direction opposite to the first direction, having a substantially cylindrical shape when viewed from the opposite direction, and formed of a dielectric;
Prepare.

A parabolic antenna according to the present disclosure includes:
lens antenna,
a parabolic reflector that reflects a high-frequency signal output from the lens antenna;
with
The lens antenna is
a waveguide section extending in a first direction and having a first cylindrical waveguide formed of a conductor, wherein a high-frequency signal is transmitted through the first waveguide;
A second cylindrical shape that is connected to the output end of the waveguide section from which the high-frequency signal is output, extends in the first direction, is formed of a conductor, and has an opening area that increases toward the first direction. a horn antenna section having a second waveguide of
a lens base portion covering an opening at an output end of the horn antenna portion for outputting the high-frequency signal, having a first surface perpendicular to the first direction, and formed of a dielectric;
a plurality of corrugated portions extending from the first surface in the first direction, having a substantially cylindrical shape when viewed from the first direction, and formed of a dielectric;
The parabolic reflector is
It has a curved surface that intersects with the first direction and that reflects the high-frequency signal output from the lens base portion and the plurality of corrugated portions.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a lens antenna capable of reducing variations in directional characteristics with respect to frequency changes.

1 is a perspective view illustrating a lens antenna according to Embodiment 1; FIG. 3 is a cross-sectional view illustrating a lens portion of the lens antenna according to Embodiment 1; FIG. FIG. 2 is a schematic diagram for explaining the principle of the lens antenna according to Embodiment 1; FIG. FIG. 11 is a perspective view illustrating a lens antenna according to Embodiment 2; FIG. 11 is a perspective view illustrating a lens antenna according to Embodiment 3; FIG. 11 is a perspective view illustrating a lens antenna according to Embodiment 4; FIG. 11 is a cross-sectional view illustrating a lens antenna according to Embodiment 5; FIG. 11 is a cross-sectional view illustrating a lens antenna according to Embodiment 6; FIG. 12 is a cross-sectional view illustrating a parabolic antenna according to Embodiment 7; FIG. 21 is a cross-sectional view illustrating a parabolic antenna according to a comparative example of the seventh embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the same reference numerals are given to the same or corresponding elements, and redundant description will be omitted as necessary for clarity of description.

[Embodiment 1]
<Configuration>
FIG. 1 is a perspective view illustrating a lens antenna according to Embodiment 1. FIG.
In FIG. 1, the horn portion 11a and the lens portion 11b of the lens antenna 11 are shown separately. In actual use, it is desirable that the horn portion 11a and the lens portion 11b are connected. That is, it is desirable that the boundary between the horn portion 11a and the lens portion 11b be in close contact so that high-frequency signals (radio waves) do not leak.
2 is a cross-sectional view illustrating a lens portion of the lens antenna according to Embodiment 1. FIG.
FIG. 2 is a cross-sectional view of the lens portion taken along line segment A1-A2 shown in FIG.

As shown in FIG. 1, the lens antenna 11 according to Embodiment 1 is composed of a lens portion 11b made of a dielectric and a horn portion 11a made of a conductor. Horn portion 11 a includes waveguide portion 111 and horn antenna portion 112 . Lens portion 11 b includes lens base portion 113 and corrugated portion 114 .

The horn antenna section 112 may have a conical shape as shown in FIG. 1, which is called a conical horn antenna. Alternatively, the waveguide portion 111 may have a circular shape as shown in FIG. Also, the lens portion is sometimes referred to as a radio wave lens.

The waveguide section 111 extends in the first direction X1 and has a first tubular-shaped first waveguide made of a conductor. A high frequency signal is transmitted through the first waveguide of the waveguide section 111 . Waveguide portion 111 may be a circular waveguide having a first waveguide of constant diameter.

The horn antenna section 112 is connected to the output end 111p of the waveguide section 111 from which the high frequency signal is output, and extends in the first direction X1. The horn antenna section 112 has a second waveguide that is formed of a conductor and has a second cylindrical shape with an opening area that increases in the first direction X1.

As shown in FIGS. 1 and 2, the lens base portion 113 covers the opening portion 112m at the output end 112p from which the high frequency signal of the horn antenna portion 112 is output, and has a first surface 113s1 perpendicular to the first direction X1. , formed of a dielectric. The lens base portion 113 may have a circular, elliptical, or polygonal shape when viewed from the first direction X1.

The corrugated portion 114 is provided to extend from the first surface 113s1 in the first direction X1, has a substantially cylindrical or annular shape when viewed from the first direction X1, is made of a dielectric material, and has a plurality of circular shapes. It has a corrugated portion that is an annular pleat. The plurality of corrugated portions are composed of, for example, a first corrugated portion 114a, a second corrugated portion 114b, and a third corrugated portion 114c, which are provided on concentric circles when viewed from the first direction X1. It has an approximately cylindrical shape.

Each corrugated portion has a different length in the first direction X1. The corrugated portion 114 includes a first corrugated portion 114a, a second corrugated portion 114b provided outside the first corrugated portion 114a, and a third corrugated portion provided outside the second corrugated portion 114b. 114c.

The height of the corrugated portion 114 becomes shorter toward the inner side. That is, the length of the first corrugated portion 114a in the first direction X1 is shorter than the length of the second corrugated portion 114b in the first direction X1. Also, the length of the second corrugated portion 114b in the first direction X1 is shorter than the length of the third corrugated portion 114c in the first direction X1. The length of the first corrugated portion 114a in the first direction X1 is called height Ha, the length of the second corrugated portion 114b in the first direction X1 is called height Hb, and the length of the third corrugated portion 114c is called height Hb. in the first direction X1 is called height Hc.

The high-frequency signal fed to the waveguide section 111 is radiated from the opening 112m of the output end 112p of the horn antenna section 112, passes through the lens section 11b, and is radiated into space (air).

<Action>
FIG. 3 is a schematic diagram for explaining the principle of operation of the lens antenna according to Embodiment 1. FIG.
As shown in FIG. 3, the high-frequency signal Hf input to the waveguide section 111 of the lens antenna 11 according to Embodiment 1 is input to the horn antenna section 112 (output end 111p of the waveguide section 111), The light is diffused in the propagation path L11 and the propagation path L21, and enters the lens base portion 113 as the high frequency signal Hf1 and the high frequency signal Hf2. High-frequency signal Hf1 passes through propagation path L12 and propagation path L13. High-frequency signal Hf2 passes through propagation path L22 and propagation path L23. The high frequency signal Hf1 and the high frequency signal Hf2 are synthesized at the opening of the lens portion 11b.

In the process of propagation of the high-frequency signal Hf, if the propagation lengths of the propagation paths L11-L12-L13 and the propagation paths L21-L22-L23 are the same, the high-frequency signal Hf1 and the high-frequency signal Hf2 are combined in phase. be. As a result, the radiation directivity of the lens antenna 11 forms a sharp beam with a narrow beam width.

On the other hand, let us consider a case where the propagation lengths of the propagation paths L11-L12-L13 and the propagation paths L21-L22-L23 are different and the phases are opposite to each other. In this case, the high-frequency signal Hf1 and the high-frequency signal Hf2 cancel each other out because they are synthesized in opposite phases. As a result, the radiation directivity of the lens antenna 11 forms a vague broad beam with a wide beam width.

Consider a case where a high-frequency signal Hf of an intermediate frequency in the frequency band used is incident on the waveguide section 111, and the high-frequency signal Hf1 and the high-frequency signal Hf2 pass through the vicinity of the second corrugated section 114b. In this case, the height of the second corrugated portion 114b is adjusted so that the phase difference between the high-frequency signal Hf1 passing through the propagation paths L11-L12-L13 and the high-frequency signal Hf2 passing through the propagation paths L21-L22-L23 is opposite in phase. If the height Hb is designed, the high-frequency signal (radio waves) radiated from the vicinity of the second corrugated portion 114b has a very wide (broad) directivity.

In order for the phase difference between the high-frequency signal Hf1 passing through the propagation paths L11-L12-L13 and the high-frequency signal Hf2 passing through the propagation paths L21-L22-L23 to be in opposite phase, The phase difference between the length and the length of the propagation paths L21-L22-L23 should be approximately 180 degrees.

Phase differences between the propagation paths L11-L12-L13 and the propagation paths L21-L22-L23 are caused by the following two causes.
First cause: the length difference between the propagation path L11 and the propagation path L21.
Second cause: the difference due to the propagation path L13 passing through the dielectric and the propagation path L23 not passing through the dielectric.

Here, the second cause is more influential and dominant than the first cause. Therefore, only the second cause will be considered. Therefore, when the phase difference caused by whether or not the dielectric is passed is taken as the phase difference δ, the phase difference δ is generally calculated as follows.

δ [degrees] = {(Hb/λ−Hb/(λ/√εr)}×360 (Formula 1)
where λ is the wavelength of the high frequency signal and εr is the effective permittivity of the dielectric.

Based on Equation 1, if the height Hb is obtained so that the phase difference δ is approximately 180 degrees, then at the frequency corresponding to the wavelength λ, a high-frequency signal (radio wave) radiated from the vicinity of the second corrugated portion 114b becomes very broad directivity.

On the other hand, since the height Ha of the first corrugated portion 114a is lower than the height Hb, the high-frequency signal passing inside the propagation path L21, that is, near the first corrugated portion 114a, has a smaller phase difference δ. and become close to the same phase.

Since the horn antenna section 112 is a kind of aperture antenna, the high-frequency signal Hf incident on the horn antenna section 112 forms a beam corresponding to the size of the aperture plane of the antenna at the output end 112p of the horn antenna section 112. be done. That is, since the wavelength is long in the low frequency band of the frequency band used, the output terminal 112p of the horn antenna section 112 has a relatively wide (broad) directivity, and the high frequency signal Hf is transmitted through the first corrugated section 114a. to the entire surface of the third corrugated portion 114c.

On the other hand, since the wavelength is short in the high frequencies of the frequency band used, the directivity at the output end 112p of the horn antenna section 112 is relatively narrow (sharp). It becomes a form that concentrates on the inner side of 114a.

Further, since the wavelength is shorter at intermediate frequencies in the frequency band used than in the case of low frequencies, the beam at output end 112p of horn antenna section 112 is narrowed down more than in the case of low frequencies. Therefore, the high-frequency signal Hf is concentrated inside the second corrugated portion 114b.

Considering the characteristics of the propagation path as described above, it is desirable to determine the height of the corrugated portion as follows.
- The height Ha of the first corrugated portion 114a is determined so that the phase difference .delta.
- The height Hb of the second corrugated portion 114b is determined so that the phase difference .delta.
- The height Hc of the third corrugated portion 114c is determined so that the phase difference .delta.

As a result, the beam width becomes broad (broad) directivity over the low frequency range to the high frequency range. That is, the change in beam width with respect to frequency change is small. Further, even when the frequency is increased, the rate (degree) of reduction in the beam width can be reduced.

As a result, it is possible to provide a lens antenna capable of reducing variations in directivity characteristics with respect to frequency changes.

Even if the number of corrugated portions 114 is one, by determining the height of the corrugated portion to a height such that the phase difference δ is 180 degrees at mid-range frequencies, compared to the case where there is no corrugated portion, It is possible to reduce variations in directivity characteristics with frequency changes.

Here, the characteristics of the height of the corrugated portion are shown below.
The height of a predetermined corrugated portion among the plurality of corrugated portions 114 is such that the phase difference δ between the first propagation path and the second propagation path is a predetermined value at a predetermined frequency in the frequency band of the high-frequency signal Hf. determined to be within the range. The predetermined range may be, for example, approximately 180 degrees, that is, 180±10 degrees.

A first propagation path is a propagation path from input to the waveguide portion 111, through the horn antenna portion 112, and through a predetermined corrugated portion.

The second propagation path enters the waveguide portion 111, passes through the horn antenna portion 112, and passes through the first surface 113s1 between the predetermined corrugated portion and the corrugated portion one inside the predetermined corrugated portion. is the propagation path until it passes through

Although the number of corrugated portions 114 has been described as three in the first embodiment, the number is not limited to this. The number of corrugated portions 114 may be a number other than three. Further, the more corrugated portions are, the greater the effect of mitigating the fluctuation of the beam width is, so it is desirable to increase the number of corrugated portions as much as possible within the allowable range of manufacturing cost and the like.

Further, the height Hc is a frequency closer to the midrange than the low range, and the height Hb is a frequency closer to the high range than the midrange. can reduce the beam width variation. Therefore, it is desirable to determine the height Hc and the height Hb in such a manner.

Further, as the horn antenna section 112, instead of the conical horn antenna, any antenna (element) among dipole antennas, loop antennas, slot antennas, patch antennas, helical antennas, spiral antennas, logarithmic periodic antennas, etc. is used. may

[Embodiment 2]
FIG. 4 is a perspective view illustrating a lens antenna according to Embodiment 2. FIG.
As shown in FIG. 4, the lens antenna 21 according to the second embodiment uses a pyramidal horn portion 21a instead of the conical horn portion 11a, unlike the lens antenna 11 according to the first embodiment. is different. That is, the waveguide portion 211 of the horn portion 21a has a rectangular shape, and the horn antenna portion 212 of the horn portion 21a has a pyramidal shape.

The pyramidal horn portion 21a is formed by joining a horn antenna portion 212 made of a conductor and having a pyramidal inside and outside and a rectangular (square) waveguide portion 211 .

The high-frequency signal Hf fed to the rectangular waveguide portion 211 of the pyramidal horn portion 21a is radiated from the opening portion 212m of the output end 212p of the horn antenna portion 212, passes through the lens portion 11b, and enters the space (in the air). radiated to At this time, by appropriately determining the height of the corrugated portion, the lens portion 11b can be operated as described in Embodiment 1, and the beam width can be prevented from being reduced even when the frequency is high. As a result, it is possible to provide a lens antenna capable of reducing variations in directivity characteristics with respect to frequency changes.

[Embodiment 3]
FIG. 5 is a perspective view illustrating a lens antenna according to Embodiment 3. FIG.

As shown in FIG. 5, the lens antenna 31 according to the third embodiment has a quad ridge portion 312 inside the horn antenna portion 112 (second waveguide), unlike the lens antenna 11 according to the first embodiment. Furthermore, the point to have is different. The quad ridge portion 312 has a first ridge portion 312a and a second ridge portion 312b.

The lens antenna 31 includes a lens portion 11b made of a dielectric material and a horn portion 31a made of a conductor having a circular or elliptical outer shape. The horn portion 31a has a configuration in which a horn antenna portion 112 having a quad ridge portion 312 inside and a circular waveguide portion 111 are joined together.

The first ridge portion 312a has a plate-like shape having a first plane including the first direction X1. The second ridge portion 312b has a plate-like shape that has a second plane that includes the first direction X1 and intersects with the first ridge portion 312a.

A high-frequency signal Hf fed to the circular waveguide portion 111 is radiated from the opening 112m of the output end 112p of the horn antenna portion 112, passes through the lens portion 11b, and is radiated into space (air). By appropriately determining the height of the corrugated portion, the beam width of the high-frequency signal Hf emitted from the lens portion 11b can be prevented from being reduced even when the frequency is high. As a result, it is possible to provide a lens antenna capable of reducing variations in directivity characteristics with respect to frequency changes.

A double ridge may be used instead of the quad ridge. A horn antenna using a quad ridge is called a quad ridge horn antenna, and a horn antenna using a double ridge is called a double ridge horn antenna.

[Embodiment 4]
FIG. 6 is a perspective view illustrating a lens antenna according to Embodiment 4. FIG.

As shown in FIG. 6, the lens antenna 41 according to Embodiment 4 uses a pyramid-shaped horn antenna section 212 and a square waveguide section 211 as compared with the lens antenna 31 according to Embodiment 3. is different.

The lens antenna 41 is composed of a lens portion 11b made of a dielectric material and a horn portion 41a made of a conductor having a pyramidal shape. The horn portion 41a has a configuration in which a horn antenna portion 212 having a quad ridge portion 312 therein and a rectangular waveguide portion 211 are joined together.

A high-frequency signal Hf fed to the rectangular waveguide portion 211 is radiated from the opening 212m of the output end 212p of the horn antenna portion 212, passes through the lens portion 11b, and is radiated into space (air). By appropriately determining the height of the corrugated portion, the beam width of the high-frequency signal Hf emitted from the lens portion 11b can be prevented from being reduced even when the frequency is high. As a result, it is possible to provide a lens antenna capable of reducing variations in directivity characteristics with respect to frequency changes.

A double ridge may be used instead of the quad ridge.

[Embodiment 5]
FIG. 7 is a cross-sectional view illustrating a lens antenna according to Embodiment 5. FIG.

As shown in FIG. 7, the lens antenna 51 according to the fifth embodiment differs from the lens antenna 11 according to the first embodiment in that the direction of the lens portion 11b is opposite. That is, a plurality of separate corrugated portions 115 are provided on the second surface 113 s 2 of the lens base portion 113 . Since the operating principle of the lens antenna 51 is the same as that of the lens antenna 11, the same effect as in the first embodiment can be obtained.

Here, the configuration of the lens antenna 51 is shown below.
The lens antenna 51 includes a horn portion 11a and a lens portion 51b. The horn portion 11 a has a waveguide portion 111 and a horn antenna portion 112 . The lens portion 51b has a lens base portion 113 and a plurality of different corrugated portions 115. As shown in FIG. In order to distinguish from the corrugated portion 114 according to the first embodiment, the corrugated portion according to the fifth embodiment is referred to as another corrugated portion 115 .

The waveguide section 111 extends in the first direction X1 and has a first cylindrical first waveguide made of a conductor, and a high-frequency signal Hf is transmitted through the first waveguide.

The horn antenna section 112 is connected to the output end 111p of the waveguide section 111 from which the high-frequency signal Hf is output, extends in the first direction X1, is formed of a conductor, and has an opening area that increases as it goes in the first direction X1. It has a second waveguide in the shape of a second cylinder.

The lens base portion 113 covers the opening portion 112m at the output end 112p of the horn antenna portion 112 from which the high-frequency signal Hf is output, and has a first surface 113s1 perpendicular to the first direction X1 and a second surface opposite to the first surface 113s1. It has a surface 113s2 and is made of a dielectric.

A plurality of other corrugated portions 115 extend from the second surface 113s2 in the direction opposite to the first direction X1, have a substantially cylindrical shape when viewed from the opposite direction, and are made of a dielectric material. The plurality of other corrugated sections 115 has a first corrugated section 115a, a second corrugated section 115b and a third corrugated section 115c.

[Embodiment 6]
FIG. 8 is a cross-sectional view illustrating a lens antenna according to Embodiment 6. FIG.

As shown in FIG. 8, the lens antenna 61 according to the sixth embodiment differs from the lens antenna 11 according to the first embodiment in that corrugated portions are provided on both sides of the lens base portion 113 . Since the operating principle of the lens antenna 61 is the same as that of the lens antenna 11, the same effect as in the first embodiment can be obtained.

The configuration of the lens antenna 61 is shown below.
The lens antenna 61 includes a horn portion 11a and a lens portion 61b. The horn portion 11 a has a waveguide portion 111 and a horn antenna portion 112 . The lens portion 61 b has a lens base portion 113 , a plurality of corrugated portions 114 , and a plurality of other corrugated portions 115 .

The lens antenna 61 differs from the lens antenna 11 in that it further includes a plurality of different corrugated portions 115 between the lens base portion 113 and the horn antenna portion 112 . In other words, both surfaces of the lens base portion 113 are provided with a plurality of annular corrugated portions made of a dielectric material.

Each of the plurality of separate corrugated portions 115 extends in a direction opposite to the first direction X1 from a second surface 113s2 opposite to the first surface 113s1 of the lens base portion 113, and has a substantially cylindrical shape when viewed from the opposite direction. and is made of a dielectric. The plurality of other corrugated sections 115 has a first corrugated section 115a, a second corrugated section 115b and a third corrugated section 115c.

[Embodiment 7]
FIG. 9 is a cross-sectional view illustrating a parabolic antenna according to Embodiment 7. FIG.
FIG. 10 is a cross-sectional view illustrating a parabolic antenna according to a comparative example of the seventh embodiment.

As shown in FIG. 9, the parabolic antenna 71 according to the seventh embodiment includes the lens antenna 11 and the parabolic reflector 12 according to the first embodiment. The parabolic reflector 12 reflects the high-frequency signal Hf output (radiated) from the lens antenna 11 .

The lens antenna 11 is, for example, a quad ridge horn antenna or a double ridge horn antenna. Since the details of the configuration of the lens antenna 11 have been described in Embodiment 1, the description thereof is omitted here.

The parabolic reflector 12 has a curved surface 12 s 1 that is a curved surface that intersects the first direction X 1 and that reflects the high-frequency signal Hf output from the lens base portion 113 and the plurality of corrugated portions 114 .

By combining the lens antenna 11 used as a primary radiator and the parabolic reflector 12, the parabolic antenna 71 realizes a wide frequency band, high efficiency and high gain antenna.

The high-frequency signal Hf (radio waves) emitted from the primary radiator (lens antenna 11) of the parabolic antenna 71 to the parabolic reflector 12 is desirably uniformly applied as shown in the directivity shown in FIG. When the beam width of the high-frequency signal Hf to be irradiated is small, as in the directivity shown in FIG. Gains commensurate with a magnitude of 12 are difficult to obtain.

Therefore, as the primary radiator (lens antenna 11), there is a need for an antenna that has a small change in beam width over a wide frequency band, that is, an antenna that does not reduce the beam width even when the frequency increases.

By using the lens antenna 11 as the primary radiator, the parabolic antenna 71 can reduce the rate (degree) of reduction in the beam width even when the frequency is increased. As a result, it is possible to provide a lens antenna capable of reducing variations in directivity characteristics with respect to frequency changes. In this way, by using the lens antenna as the primary radiator of the parabolic antenna, a high-efficiency, high-gain parabolic antenna can be realized.

In addition, a large site is required to install a large-diameter parabolic antenna. Therefore, by using a parabolic antenna using a lens antenna, a plurality of frequency bands can be aggregated and functions can be shared, so that a large installation space is not required and costs can be reduced.

It should be noted that while details of several specific embodiments are included in the above discussion, these should not be construed as limitations on the scope of this disclosure, but as illustrations of features specific to those particular embodiments. should. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable combination.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the invention.

It should be noted that the present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 11, 21, 31, 41, 51, 61... Lens antenna 71... Parabolic antenna 11a, 21a, 31a, 41a... Horn part 11b, 51b... Lens part 12... Parabolic reflector 12s1... Curved surface 111, 211... Waveguide part 111p, 112p, 212p output end 112m, 212m opening 112, 212 horn antenna 312 quad ridge 312a first ridge 312b second ridge 113 lens base 113s1 first surface 113s2... Second surface 114... Corrugated part 114a... First corrugated part 114b... Second corrugated part 114c... Third corrugated part 115... Another corrugated part 115a... First corrugated part 115b... Second corrugated part 115c Third corrugated portion L11, L12, L13, L21, L22, L23 Propagation path Hf, Hf1, Hf2 High frequency signal Ha, Hb, Hc Height δ Phase difference λ Wavelength εr Effective permittivity X1 …first direction

Claims (10)

a waveguide section extending in a first direction and having a first cylindrical waveguide formed of a conductor, wherein a high-frequency signal is transmitted through the first waveguide;
A second cylindrical shape that is connected to the output end of the waveguide section from which the high-frequency signal is output, extends in the first direction, is formed of a conductor, and has an opening area that increases toward the first direction. a horn antenna section having a second waveguide of
a lens base portion covering an opening at an output end of the horn antenna portion for outputting the high-frequency signal, having a first surface perpendicular to the first direction, and formed of a dielectric;
a plurality of corrugated portions extending from the first surface in the first direction, having a substantially cylindrical shape when viewed from the first direction, and formed of a dielectric;
A lens antenna with a Each of the plurality of corrugated portions has a different length in the first direction,
The lens antenna according to claim 1. The plurality of corrugated parts includes a first corrugated part, a second corrugated part provided outside the first corrugated part, and a third corrugated part provided outside the second corrugated part and having
The lens antenna according to claim 1 or 2. The length of the first corrugated portion in the first direction is shorter than the length of the second corrugated portion in the first direction,
The length of the second corrugated portion in the first direction is shorter than the length of the third corrugated portion in the first direction,
The lens antenna according to claim 3. The height of a predetermined corrugated portion among the plurality of corrugated portions has a predetermined phase difference between the first propagation path and the second propagation path at a predetermined frequency in the frequency band of the high-frequency signal. is determined to be within the range of
The first propagation path is from input to the waveguide section, passes through the horn antenna section, and passes through the predetermined corrugated section,
The second propagation path is input to the waveguide section, passes through the horn antenna section, and is located between the predetermined corrugated section and the corrugated section one inside the predetermined corrugated section. until it passes through the first plane,
The lens antenna according to any one of claims 1 to 4. The waveguide section has a circular or rectangular shape,
The horn antenna section has a conical or pyramidal shape,
The lens antenna according to any one of claims 1 to 5. further having a quad ridge portion inside the horn antenna portion;
The quad ridge portion is
a plate-shaped first ridge portion having a first plane including the first direction;
a plate-shaped second ridge that has a second plane that includes the first direction and that intersects with the first ridge;
The lens antenna according to any one of claims 1 to 6. Further comprising a plurality of separate corrugated parts between the lens base part and the horn antenna part,
Each of the plurality of different corrugated sections,
It extends in the direction opposite to the first direction from a second surface opposite to the first surface of the lens base portion, has the substantially cylindrical shape when viewed from the opposite direction, and is made of a dielectric material. ,
The lens antenna according to any one of claims 1 to 7. a waveguide section extending in a first direction and having a first cylindrical waveguide formed of a conductor, wherein a high-frequency signal is transmitted through the first waveguide;
A second cylindrical shape that is connected to the output end of the waveguide section from which the high-frequency signal is output, extends in the first direction, is formed of a conductor, and has an opening area that increases toward the first direction. a horn antenna section having a second waveguide of
Covering the opening at the output end of the horn antenna section for outputting the high-frequency signal, having a first surface perpendicular to the first direction and a second surface opposite to the first surface, and made of a dielectric material a formed lens base;
a plurality of other corrugated portions extending from the second surface in a direction opposite to the first direction, having a substantially cylindrical shape when viewed from the opposite direction, and formed of a dielectric;
A lens antenna with a lens antenna,
a parabolic reflector that reflects a high-frequency signal output from the lens antenna;
with
The lens antenna is
a waveguide section extending in a first direction and having a first cylindrical waveguide formed of a conductor, wherein a high-frequency signal is transmitted through the first waveguide;
A second cylindrical shape that is connected to the output end of the waveguide section from which the high-frequency signal is output, extends in the first direction, is formed of a conductor, and has an opening area that increases toward the first direction. a horn antenna section having a second waveguide of
a lens base portion covering an opening at an output end of the horn antenna portion for outputting the high-frequency signal, having a first surface perpendicular to the first direction, and formed of a dielectric;
a plurality of corrugated portions extending from the first surface in the first direction, having a substantially cylindrical shape when viewed from the first direction, and formed of a dielectric;
The parabolic reflector is
Having a curved surface that intersects with the first direction and that reflects the high-frequency signal output from the lens base portion and the plurality of corrugated portions,
parabolic antenna.

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