JP4178265B2 - Waveguide horn antenna, antenna device, and radar device - Google Patents

Description

  The present invention relates to a waveguide horn antenna that emits and receives high-frequency signals such as millimeter waves, and an antenna device and a radar device including the waveguide horn antenna.

  In a radar apparatus using a millimeter wave band, a waveguide antenna has a smaller transmission loss than a planar circuit such as a microstrip line. Many are used. In such a waveguide antenna, an opening is provided by providing a tapered portion on the opening side so that the cross-sectional area of the waveguide increases from the feeding portion toward the opening. The structure which makes the electromagnetic wave radiated | emitted from a part the plane wave form is utilized (for example, refer patent document 1).

FIG. 10 is an external perspective view showing a schematic structure of a conventional waveguide horn antenna as shown in Patent Document 1. FIG.
As shown in FIG. 10, the conventional waveguide horn antenna has a structure in which a feeding waveguide 93, a connection waveguide 91, and a horn-type waveguide 92 are formed on a substantially cylindrical conductor member 90.

  The feed waveguide 93 is formed in a cylindrical shape with a predetermined diameter on the central axis of the conductor member 90, and the connection waveguide 91 is located at a predetermined distance from the short-circuited end of the feed waveguide 93. It is formed in a rectangular tube shape extending linearly in a direction perpendicular to the electromagnetic wave propagation direction. The horn-type waveguide 92 extends in the same axial direction as the connection waveguide 91 and is formed in a taper shape, and the cross-sectional area of the waveguide gradually increases from the end on the connection waveguide 91 side to the opening surface. It is formed in the shape.

  In the horn antenna having such a configuration, in order to make the electromagnetic wave radiated from the opening into a more uniform plane wave, the length of the tapered waveguide must be increased. The shape of the radar device provided becomes large.

Thus, there is a waveguide horn antenna that keeps the length of the waveguide long and has a small external dimension, and is formed by folding the waveguide about 180 ° (see, for example, Patent Document 2).
JP-A-4-301902 JP 2001-284912 A

  However, as described above, the waveguide horn antenna of Patent Document 1 may not be able to reduce the size of the device in order to obtain an outer shape that provides desired antenna characteristics. On the other hand, since the waveguide horn antenna of Patent Document 2 has a shape in which the waveguide is folded back by 180 °, reflection loss increases at the folded portion, transmission characteristics deteriorate, and it is difficult to obtain a desired output. The problem that occurred.

  Therefore, an object of the present invention is to provide a small-sized waveguide horn antenna excellent in radiation characteristics and transmission characteristics, and to provide an antenna device and a radar device using the waveguide horn antenna. .

In the present invention, a feed waveguide extending in a predetermined direction and a direction perpendicular to the signal propagation direction of the feed waveguide is a radiation direction, and a signal is radiated with respect to the area of the connection surface with the feed waveguide. And a radiating waveguide having a wide opening surface area, the radiating waveguide from the end on the connection surface side to the end on the opening surface side. In addition, the cross-sectional area perpendicular to the extending direction of the radiating waveguide gradually increases and is formed in a shape extending in a non-linear shape .

  In this configuration, a signal (electromagnetic wave) input to the feed waveguide is propagated to the radiation waveguide through the feed waveguide. The signal propagated to the radiating waveguide propagates through the waveguide formed in a shape that extends in a non-linear manner and has an opening area wider than the area of the end face on the feeding waveguide side. Radiated from the surface. At this time, the radiating waveguide has a wide opening shape with respect to the end surface on the feeding waveguide side, so that it was a plane wave when it was input from the feeding waveguide to the radiating waveguide. The signal has a spherical wave shape on the aperture surface. Since the radiating waveguide extends in a non-linear shape, the length of the signal propagation path of the waveguide becomes longer than when the waveguide is linearly formed. As a result, if the linear distance from the feed waveguide side end face of the radiating waveguide to the opening face is the same, the spherical wave signal is made more planar wave than when the waveguide is formed linearly. Thus, the radiation characteristics are improved. On the other hand, if the same radiation characteristics are to be obtained, the distance from the feed waveguide side end surface to the opening surface is shorter than when the waveguide is formed in a straight line, and the waveguide horn antenna is downsized. Is done.

  In this configuration, the radiating waveguide is divided into a portion where the cross-sectional area on the feeding waveguide side extends non-linearly and a portion where the cross-sectional area on the opening surface side extends linearly like a conventional horn antenna. Rather than forming, the entire waveguide is formed in a shape that spreads in a non-linear manner, so that there is no connection between the two portions, transmission loss due to discontinuity of this connection is reduced, and the waveguide Shape design becomes easy.

  In the waveguide horn antenna of the present invention, the radiating waveguide is formed in a logarithmic spiral shape with the central axis of the feeding waveguide parallel to the extending direction of the feeding waveguide as the center of the spiral. It is characterized by.

  In this configuration, as a specific example of the above-described non-linear shape, the radiation waveguide is formed in a logarithmic spiral shape, so that it extends non-linearly and has a cross-sectional area from the end surface on the feeding waveguide side to the opening surface. A gradually expanding waveguide horn antenna can be formed relatively easily.

  The waveguide horn antenna according to the present invention is characterized in that a radiation waveguide is formed from two conductor members that are brought into contact with each other on a plane to be divided into E planes.

  In this configuration, a groove extending in a non-linear manner with a predetermined depth is formed in the two conductor members. At this time, the grooves formed in the two conductor members are formed so that the positions of the grooves coincide when the two conductor members are placed in contact with each other with the groove sides facing each other. Further, the height of the side surface of the groove formed in the two conductor members is the same, and the height of the side surface of the waveguide formed by contacting the two conductor members is the width of the bottom surface of the groove. The groove is formed so as to be longer than the width of the bottom surface of the waveguide, that is, the length between the side surfaces. By setting it as such a structure, the surface parallel to the bottom face of a groove | channel (waveguide) becomes an E surface, and the contact surface of two conductor members becomes an E surface division surface. And since the waveguide is formed by the conductor member to be joined at the E plane dividing surface, the leakage of the electromagnetic wave being propagated is reduced.

  Further, the antenna device of the present invention is connected to the above-described waveguide horn antenna and a feeding waveguide of the waveguide horn antenna, and a signal to the feeding waveguide or a signal from the feeding waveguide And a rotating means for rotating the waveguide horn antenna about the central axis of the feeding waveguide with respect to the fixed waveguide. It is characterized by that.

  In this configuration, the above-described waveguide horn antenna radiates the electromagnetic wave input from the fixed waveguide while being rotated by the rotating means, and also receives the electromagnetic wave (reflected wave) received from the outside to the fixed waveguide. Propagate. For this reason, radiation and reception of electromagnetic waves are performed in the entire circumferential direction parallel to the radiation direction of the waveguide horn antenna.

  A radar apparatus according to the present invention includes the above-described antenna apparatus, and performs detection based on a signal radiated from the antenna apparatus and a signal received by the antenna apparatus.

  In this configuration, since the electromagnetic wave in all directions is radiated and received by the antenna device described above, the distance and magnitude from the electromagnetic wave radiated by itself and the received reflected wave to the target are detected.

  According to the present invention, by forming the waveguide whose cross-sectional area is widened toward the opening surface in a non-linear shape, specifically in a logarithmic spiral shape, the same outer shape is formed rather than forming the waveguide in a linear shape. If so, the radiation characteristics can be further improved, and if the radiation characteristics are comparable, a more compact waveguide horn antenna can be configured. Furthermore, it is possible to construct a small-sized waveguide horn antenna that is superior in radiation characteristics than the conventional linear waveguide. And by making this waveguide into one kind of non-linear shape, specifically logarithmic spiral shape throughout, it is possible to suppress transmission loss during waveguide transmission and facilitate the design of the waveguide. it can. That is, a small waveguide horn antenna having excellent radiation characteristics can be configured with a simple structure.

  In addition, according to the present invention, a waveguide horn antenna can be formed simply by superimposing two conductor members, and transmission loss is suppressed by superimposing them on the E plane dividing surface. That is, a waveguide horn antenna having a simple structure and excellent radiation characteristics can be easily manufactured.

  Moreover, according to this invention, the small-sized antenna apparatus excellent in the radiation | emission characteristic can be comprised by using the above-mentioned waveguide horn antenna.

  Further, according to the present invention, by using the antenna device including the waveguide horn antenna, a radar device having excellent detection performance can be configured in a small size.

A waveguide horn antenna according to a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1A is an external perspective view showing a schematic configuration of the waveguide horn antenna of the present embodiment, and FIG. 1B is a perspective view showing a configuration of a portion functioning as a waveguide.
As shown in FIG. 1, the waveguide horn antenna of the present embodiment includes a radiation waveguide 1 and a feed waveguide 3 formed on a conductor member 2. The radiating waveguide 1 includes a logarithmic spiral waveguide 11 and a horn-type waveguide 12, and one end of the horn-type waveguide 12 opens to the outside from the conductor member 2. One end of the tube 11 is connected to the feed waveguide 3. Here, for convenience of the following description, the opening end surface of the horn-shaped waveguide 12 is defined as the opening surface 101, and the connection surface of the logarithmic spiral waveguide 11 to the power supply waveguide 3 is defined as the power supply side connection surface. 103, and the connection surface between the horn-type waveguide 12 and the logarithmic spiral waveguide 11 is an intermediate connection surface 102.

  The feed waveguide 3 is a cylindrical waveguide formed on the conductor member 2 and is formed in a shape extending linearly along the axial direction of the cylinder. At a position away from the short-circuited end of the power supply waveguide 3 (the upper end of the power supply waveguide 3 in FIG. 1) by a predetermined distance, one end of a square cylindrical logarithmic spiral waveguide 11 extending in a logarithmic spiral shape is located. It is connected. The shape of this connecting portion is formed in a shape in which the cylindrical power supply waveguide 3 and each cylindrical logarithmic spiral waveguide 11 are coupled, and the TM propagating through the cylindrical power supply waveguide 3 is formed. The mode and the TE mode propagating through the square cylindrical logarithmic spiral waveguide are mutually converted. Furthermore, the connection position is propagated between the TM mode propagating through the cylindrical power supply waveguide 3 and the square cylindrical logarithmic spiral waveguide 11 between the power supply waveguide 3 and the logarithmic spiral waveguide 11. The TE mode to be converted is set to a position for converting with low loss.

  The logarithmic spiral waveguide 11 of the radiating waveguide 1 has a rectangular cross section perpendicular to the extending direction, and is connected to the horn-type waveguide 12 from the feeding-side connection surface 103 connected to the feeding waveguide 3. In a plane perpendicular to the central axis of the feed waveguide 3 up to the intermediate connection surface 102, the central connection surface 102 is formed in a shape that is curved at approximately 270 ° with the central axis as the center of the spiral. Here, the electromagnetic wave incident direction of the logarithmic spiral waveguide 11 is a direction perpendicular to the feeding-side connection surface 103, and this direction is a central axis direction of the feeding waveguide 3, that is, a direction perpendicular to the signal propagation direction. The electromagnetic wave emission direction of the logarithmic spiral waveguide 11 is a direction perpendicular to the intermediate connection surface 102, and this direction is also a direction perpendicular to the signal propagation direction of the feed waveguide 3.

  Specifically, the logarithmic spiral waveguide 11 is formed, for example, in a shape extending according to the following logarithmic spiral equation with respect to a plane perpendicular to the central axis of the feed waveguide 3.

  Here, the equation of the logarithmic spiral is given by r = R × exp (cot α × θ), (r, θ) indicates polar coordinates, and the point of the central axis of the feed waveguide 3 is the origin of this polar coordinate system. . R and α are constants, and the spiral shape is determined by setting the values of R and α to predetermined values. At this time, an inner line wound around the logarithmic spiral waveguide 11 (an inner side surface around which the logarithmic spiral waveguide 11 is wound) projected onto a plane perpendicular to the central axis of the feed waveguide 3, and By appropriately setting the constants R and α on the outer line wound by the logarithmic spiral waveguide 11 (the outer side surface wound by the logarithmic spiral waveguide 11), the space between the lines gradually widens. A logarithmic spiral waveguide 11 is formed. That is, by performing such setting, the interval between the inner side surface and the outer side surface in the logarithmic spiral waveguide 11 is formed in a shape that gradually increases from the power supply side connection surface 103 to the intermediate connection surface 102.

  The logarithmic spiral waveguide 11 is formed in a shape extending in the direction parallel to the central axis of the feed waveguide 3 from the connection position toward the short-circuit end of the feed waveguide 3. Here, the bottom surface of the logarithmic spiral waveguide 11 (the lower surface of the logarithmic spiral waveguide 11 in the figure) and the top surface of the logarithmic spiral waveguide 103 (the logarithmic spiral shape in the figure). (The upper surface of the waveguide 11) differs in the amount of extension in the direction parallel to the central axis, and the distance between the bottom surface and the top surface gradually increases from the power supply side connection surface 103 to the intermediate connection surface 102. Is formed.

  By being formed in such a shape, the logarithmic spiral waveguide 11 is cut perpendicular to the extending direction of the waveguide from the end on the power supply side connection surface 103 side to the end on the intermediate connection surface 102 side. The shape is such that the area gradually increases and the waveguide extends while being curved.

  The horn-type waveguide 12 is formed in a tapered shape in which each wall surface is linear and gradually extends from the intermediate connection surface 102 to the opening surface 101, and the area of the opening surface 101 is larger than the area of the intermediate connection surface 102. Widely formed. The direction perpendicular to the opening surface 101 is the same as the direction perpendicular to the intermediate connection surface 102, and the electromagnetic wave radiation direction of the opening surface 101 is perpendicular to the signal propagation direction of the feed waveguide 3.

  With such a configuration, the distance from the feeding-side connecting surface 103 to the opening waveguide 101 with the feeding waveguide 3 is longer than that of the conventional radiation waveguide extending linearly, and in the extending direction. Since the vertical cross-sectional area gradually increases, electromagnetic waves are radiated in a state closer to a plane wave than in the conventional structure while propagating through the logarithmic spiral waveguide 11 and the horn waveguide 12. . Thereby, the beam width of the radiated electromagnetic wave can be narrowed, and the antenna gain can be increased. Furthermore, although it is small in size, there is no sudden change in the direction of the transmission line, such as bending the waveguide 180 ° as in the conventional case, and it is a shape that extends while gently curving. Loss can be greatly suppressed.

  For example, when the radius of the cylindrical portion of the conductor member 2 is 15 mm and the logarithmic spiral waveguide 11 having a 270 ° curve shape as shown in FIG. 1 is used, the parameters of the logarithmic spiral equation for the inner side wall of the winding are set as follows. Let R = 6, α = −88 °, and let the parameters of the logarithmic spiral equation for the outer sidewall of the winding be R = 7.27, α = 88 °. Furthermore, while the height (h3) of the power supply side connection surface 103 is 2.54 mm and the width (w3) is 1.27 mm, the height (h2) of the intermediate connection surface 102 is 6.0 mm, The width (w2) is 3.5 mm, the height (h1) of the opening surface 101 is 15 mm, and the width (w1) is 12 mm. Further, the length of the horn type waveguide 12 is set to 21.635 mm. When the horn antenna is formed under such conditions, directivity as shown in FIG. 2 is obtained.

  FIG. 2 is a diagram showing the directivity of the horn antenna having the structure of the present embodiment and the horn antenna having the structure of the conventional example, where (a) shows the vertical directivity and (b) shows the horizontal directivity. . As shown in this result, by adopting the configuration of the present embodiment, both the vertical directivity and the horizontal directivity are improved as compared with the conventional example. As specific numerical values in this experimental result, the horn antenna having the structure of the present embodiment has a vertical beam width of 16.5 ° (21.3 ° in the conventional example (structure of FIG. 10)) and a horizontal beam width of 18 °. .4 ° (18.7 ° in the conventional example) and antenna gain of 19.5 dBi (17.4 dBi in the conventional example), it can be seen that each characteristic is improved as compared with the conventional case.

Next, a method for forming the waveguide horn antenna of this embodiment will be described with reference to FIG.
FIG. 3 is an exploded perspective view in which the waveguide horn antenna shown in FIG. 1 is separated for each component.
As shown in FIG. 3, the waveguide horn antenna includes an upper conductor member 21 and a lower conductor member 22. The upper conductor member 21 is formed with a logarithmic spiral groove 111 and a power feeding cylindrical hole 31 connected in order from the horn groove 121 opened on the side surface in the center direction. The horn groove 121 is formed in a shape that opens on the side surface of the upper conductor member 21 and gradually decreases in depth from the opening toward the substantially central direction of the upper conductor member 21 and narrows in width. The logarithmic spiral groove 111 is connected to the horn-type waveguide groove 121 and is formed in such a shape that the depth gradually decreases from the end connected to the horn-type waveguide groove 121 to the end facing the horn-type waveguide groove 121. ing. The power feeding cylindrical hole 31 is formed substantially at the center of the bottom surface (the lower surface in FIG. 3) of the upper conductor member 21, and is connected to the logarithmic spiral groove 111 and formed at a predetermined depth and a predetermined diameter. Here, the side wall of the logarithmic spiral groove 111 is formed in a shape according to the above-described logarithmic spiral equation, and the constants R and α given to the respective side walls are different.

  The lower conductor member 22 has a shape facing the upper conductor member 21 and is formed by connecting a logarithmic spiral groove 112 and a power feeding cylindrical hole 32 in this order from a horn groove 122 opened on a side surface in the center direction. The horn groove 122 is formed in a shape that opens on the side surface of the lower conductor member 22 and gradually becomes shallower and narrower from the opening toward the substantially central direction of the lower conductor member 22. The logarithmic spiral groove 112 is connected to the horn-type waveguide groove 122 and is formed in such a shape that the depth gradually decreases from the end connected to the horn-type waveguide groove 122 to the end facing the horn-type waveguide groove 122. ing. The power feeding cylindrical hole 32 is formed substantially at the center of the bottom surface (upper surface in FIG. 3) of the upper conductor member 22, and is connected to the logarithmic spiral groove 112 and formed at a predetermined depth and a predetermined inner diameter. Here, the side wall of the logarithmic spiral groove 112 is formed in a shape according to the above-described logarithmic spiral equation, and the constants R and α given to the respective side walls are different.

  By adopting such a configuration, when the upper conductor member 21 and the lower conductor member 22 are brought into contact with each other on the surfaces on which the respective grooves are formed, the horn groove 121 and the horn groove 122 are shown in FIG. A horn-type waveguide 12 is formed, the logarithmic spiral groove 111 and the logarithmic spiral groove 112 form the logarithmic spiral waveguide 11 shown in FIG. 1 is formed. These grooved conductor members are formed by cutting or die-casting the conductor member, or by forming a shape in advance with resin, ceramic or glass and then plating with a conductive material, or by forging press. It is.

  Here, the height of the logarithmic spiral waveguide 11 is set to be longer than the width. That is, the total depth of the logarithmic spiral groove 111 and the logarithmic spiral groove 112 is set to be longer than the width of the logarithmic spiral grooves 111 and 112. As a result, the contact surface between the upper conductor member 21 and the lower conductor member 22 becomes the E plane dividing surface of the horn-type waveguide 12 and the logarithmic spiral waveguide 11. As a result, the transmission loss of the electromagnetic wave transmitted through the waveguide is greatly increased even when the conductor member 2 is divided into two parts, the upper conductor member 21 and the lower conductor member 22, and these are in contact with each other. Can be suppressed. As a result, a waveguide horn antenna with little transmission loss and excellent antenna radiation characteristics can be formed.

  In addition, since the logarithmic spiral waveguide 11 is formed around the circumferential surface with the feeding waveguide 3 as the center, the outer shape can be reduced while the waveguide length is increased.

  By setting it as the above structures, the small horn antenna excellent in the radiation | emission characteristic and the transmission characteristic can be formed.

  In the above description, the example in which the radiating waveguide 1 is formed of the logarithmic spiral waveguide 11 and the horn-type waveguide 12 has been described. However, the entire radiating waveguide 1 is logarithmically spiraled. You may form in. In this case, the shape of the wall surface in plan view of the radiation waveguide is, for example, as shown in FIG.

FIG. 4 is a diagram showing the trajectory of the wall surface when the entire radiation waveguide is formed in a logarithmic spiral, 201 indicates the inner wall surface of the radiation waveguide, and 202 indicates the outside of the radiation waveguide. Shows the wall.
As shown in FIG. 4, even if the whole radiation waveguide is made into a logarithmic spiral, the same effects as those of the above-described configuration can be obtained. Furthermore, when there are a logarithmic spiral extending portion and a linearly extending portion as in the above-described configuration, it is necessary to design so that no transmission loss occurs between them. If it is a spiral shape, it is possible to suppress transmission loss at this connection portion, and it is not necessary to design this portion, and the shape can be easily designed.

  Further, as described above, in the configuration of FIG. 1, the example using the logarithmic spiral waveguide curved at 270 ° and the example using the logarithmic spiral waveguide curved at 360 ° are explained in FIG. May be set as appropriate according to the specifications of the required waveguide horn antenna.

Next, a waveguide horn antenna according to a second embodiment will be described with reference to the drawings.
FIG. 5A is an external perspective view showing a schematic structure of the waveguide horn antenna of the present embodiment, and FIG. 5B is an external perspective view showing a configuration of a conventional waveguide horn antenna. .
The waveguide horn antenna of this embodiment is obtained by connecting a logarithmic spiral waveguide to a conventional H-plane spectral horn.
As shown in FIG. 5A, the waveguide horn antenna of this embodiment has a structure in which a horn-type waveguide 43 and a logarithmic spiral waveguide 42 are formed on a conductor plate 41 having a predetermined thickness. The horn-type waveguide 43 and the logarithmic spiral waveguide 42 have the same thickness d.

  The horn-type waveguide 43 is opened from one surface of the conductor plate 41, has a linearly extending shape inside, and is formed in a tapered shape with a gradually narrowing width, and with respect to the width w44 of the opening surface 44, The width w46 of the connection surface with the logarithmic spiral waveguide 42 is narrow.

  The logarithmic spiral waveguide 42 is connected to the horn-type waveguide 43 and has a side wall extending non-linearly according to the logarithmic spiral equation shown in the first embodiment. The opening is made in a plane that is parallel to the opening surface 44 and is formed on substantially the same plane as the connection surface between the horn waveguide 43 and the logarithmic spiral waveguide 42. Then, by setting the constants of the logarithmic spiral equation for forming both side surfaces to different predetermined values, the width w45 of the opening surface 45 becomes narrower than the width w46 of the connection surface, so that It is formed in a shape that gradually decreases in width toward 45. The opening surface 45 of the logarithmic spiral waveguide 42 is connected to a feed waveguide (not shown).

  On the other hand, the conventional H-plane spectral horn has a structure in which a horn-type waveguide 83 and a linear waveguide 82 are formed on a conductor plate 81 having a predetermined thickness, and the horn-type waveguide 83 and the linear waveguide are formed. The thickness d of the tube 82 is the same.

  The horn-type waveguide 83 is opened from one surface of the conductor plate 81, has a shape extending linearly inside, and is gradually formed with a shape that is not narrow, and is linear with respect to the width w 84 of the opening surface 84. The width w86 of the connection surface with the waveguide 82 is narrow.

  The straight waveguide 82 coincides with the side surface of the conductor plate 81 having the opening surface 84 of the horn-type waveguide 83 without changing the width, with the central axis in the extending direction coincident with that of the horn-type waveguide 83. It is formed in a shape that opens from the side surface. For this reason, the width w85 of the opening surface 85 is the same as the width w86 of the connection surface. The straight waveguide 82 is connected to a feed waveguide (not shown) at the opening surface 85.

As can be seen by comparing FIGS. 5 (a) and 5 (b), by using the configuration of this embodiment, even if the length parallel to the direction in which the horn-type waveguide extends in the conductor plate is the same, The substantial waveguide length from the feeding waveguide to the opening surface of the horn-type waveguide can be increased. As a result, as shown in FIG. 6, the supplied electromagnetic wave is maintained in a state closer to a plane wave, so that the beam width is narrowed and the radiation characteristics of the antenna are improved. For example, the parameters of the inner side wall to be wound are R = 6, α = −86 °, the parameters of the outer side wall to be wound are R = 8.54, α = 86 °, and the opening surface 45 is rotated. The dimensions of the connection surface 46 are 5.8 mm × 1.27 mm, the opening surface 44 is 12 mm × 1.27 mm, and the length of the horn-type waveguide is 15 mm. In this case, the horizontal beam width is 17.6 ° (26.0 ° in the conventional example (structure of FIG. 5B)), and the antenna gain is 13.1 dBi (11.5 dBi in the conventional example).
FIG. 6A shows the electric field intensity distribution of the waveguide horn antenna of the present embodiment (structure of FIG. 5A), and FIG. 6B shows the conventional structure (structure of FIG. 5B). The electric field strength distribution of a waveguide horn antenna is shown. FIG. 7 is a diagram showing the directivity and reflection characteristics of the waveguide horn antenna having the structure of this embodiment and the conventional waveguide horn antenna. Thus, by using the structure of the present embodiment, the directivity and the radiation characteristics of the antenna can be improved.

  In the structure of the present embodiment, the conductor plate is connected to the power supply waveguide at approximately the center in the direction in which the horn-shaped waveguide extends. Therefore, even if the shape of the power supply waveguide is taken into consideration, the overall dimensions in this direction Thus, a small-sized waveguide horn antenna can be configured.

  The following logarithmic spiral equation may be used for the waveguide horn antenna of each of the embodiments described above.

R in this case, theta also shows a polar, R, a _n, by properly setting the N, it is possible to obtain a desired logarithmic spiral.

Next, an antenna device according to a third embodiment will be described with reference to FIG.
FIG. 8 is a diagram showing a schematic configuration of an antenna apparatus using the waveguide horn antenna shown in FIG.
The antenna device shown in FIG. 8 includes a waveguide horn antenna 51, a fixing member 52, and a choke 53. The waveguide horn antenna 51 is composed of a conductor member 2 on which a radiation waveguide 1 and a power supply waveguide 3 are partially formed of a logarithmic spiral waveguide. The fixed member 52 is connected to the feeding waveguide 3 of the waveguide horn antenna 1 and includes a fixed feeding waveguide 54 having the same cross-sectional shape. The choke 53 includes a connection waveguide 55 that rotatably supports the waveguide horn antenna 1 with respect to the fixed member 52 and connects the feed waveguide 3 and the fixed feed waveguide 54. The waveguide horn antenna 51 is rotated with respect to the fixed member 52 by a rotational power source (not shown). An antenna parallel to the radiation direction of the antenna is supplied by supplying electromagnetic waves from the fixing member 52 to the waveguide horn antenna 51 while rotating in this way and radiating the electromagnetic waves from the radiation opening 50 of the waveguide horn antenna 51 to the outside. Electromagnetic waves can be radiated in the entire circumferential direction of the apparatus.

  By using the waveguide horn antenna of the first embodiment described above for such an antenna device, the antenna device can be miniaturized and radiate electromagnetic waves with excellent radiation characteristics over the entire circumference. be able to.

Next, a radar apparatus according to a fourth embodiment will be described with reference to FIG.
FIG. 9 is a block diagram showing a schematic configuration of the radar apparatus of the present embodiment.
The radar apparatus according to the present embodiment includes an antenna apparatus 60, a voltage control oscillator 61, a directional coupler 62, a circulator 63, a mixer 64, and an LNA 65. And the antenna apparatus provided with the above-mentioned waveguide horn antenna is used for this antenna apparatus 60. FIG.

  In the radar apparatus having such a configuration, detection is performed by the following operation. The voltage controlled oscillator 61 generates an oscillation signal and outputs it to the antenna device 60 via the directional coupler 62 and the circulator 63. The antenna device 60 radiates (transmits) an oscillation signal as a transmission signal to a predetermined external detection area. Further, the directional coupler 62 distributes power of the input oscillation signal to generate a local signal and outputs it to the mixer 64. On the other hand, the antenna device 60 outputs the received signal to the mixer 64 via the circulator 63. The mixer 64 down-converts the received signal input from the circulator 63 with the local signal input from the directional coupler 62 to generate an intermediate frequency signal IF and outputs it to the LNA 65. The LNA 65 amplifies the intermediate frequency signal IF. And output as a detection signal.

  In the radar apparatus having such a configuration, by using the antenna apparatus including the above-described waveguide horn antenna, radiation characteristics such as directivity of a transmission signal are excellent, and radar detection characteristics are improved. Furthermore, since the waveguide horn antenna is downsized, a small radar device having excellent radar detection characteristics can be configured.

It is the external appearance perspective view which shows schematic structure of the horn antenna of 1st Embodiment, and the perspective view which shows the structure of the part which functions as a waveguide. It is a figure which shows the directivity of the horn antenna of the structure of 1st Embodiment, and the horn antenna of the structure of a prior art example. It is the disassembled perspective view which isolate | separated the horn antenna shown in FIG. 1 for every component. It is a figure which shows the track | orbit of a wall surface at the time of forming the whole radiation waveguide in logarithmic spiral form. It is the external appearance perspective view which shows schematic structure of the horn antenna of 2nd Embodiment, and the external appearance perspective view which shows the structure of the conventional same horn antenna. It is a figure which shows the electric field strength distribution of the horn antenna of the structure of Fig.5 (a), and the electric field strength distribution of the horn antenna of the structure of FIG.5 (b). It is the figure which showed the directivity and reflection characteristic of the horn antenna of the structure of 2nd Embodiment, and the conventional horn antenna. It is a figure which shows schematic structure of the antenna apparatus using the horn antenna shown in FIG. It is a block diagram which shows schematic structure of the radar apparatus of 4th Embodiment. It is an external appearance perspective view which shows schematic structure of the conventional horn antenna.

Explanation of symbols

1-radiation waveguide 11-logarithmic spiral waveguide 12-horn type waveguide 2-conductor member 3-feeding waveguide 21-upper conductor member 22-lower conductor member 121,122-horn groove 111 112-logarithmic spiral groove 201-inner wall surface 202-outer wall surface 31,32-feeding cylindrical hole 40-radiation waveguide 41-conductor plate 42-logarithmic spiral waveguide 43-horn type waveguide 51- Waveguide horn antenna 52-Fixed member 53-Choke 54-Fixed feed waveguide 55-Connection waveguide 60-Antenna device 61-Voltage controlled oscillator 62-Directional coupler 63-Circulator 64-Mixer 65-LNA

Claims (5)

A feeding waveguide extending in a predetermined direction;
Radiation in which the direction perpendicular to the signal propagation direction of the feed waveguide is the radiation direction, and the area of the opening surface where the signal is radiated is larger than the area of the connection surface with the feed waveguide And a waveguide horn antenna comprising:
The radiation waveguide has a non-linear shape with a gradually increasing cross-sectional area perpendicular to the direction in which the radiation waveguide extends from the end on the connection surface side to the end on the opening surface side. A waveguide horn antenna characterized by being formed in an extending shape . 2. The waveguide according to claim 1 , wherein the radiation waveguide is formed in a logarithmic spiral shape with the center axis of the feed waveguide parallel to the extending direction of the feed waveguide as a spiral center. Horn antenna. 3. The waveguide horn antenna according to claim 1 , wherein the radiation waveguide is formed of two conductor members that are in contact with each other at a plane dividing the E waveguide. The waveguide horn antenna according to any one of claims 1 to 3 ,
A fixed waveguide connected to the feed waveguide of the waveguide horn antenna, propagating a signal to the feed waveguide or a signal from the feed waveguide, and fixed to the device;
Rotating means for rotating the waveguide horn antenna about the central axis of the feeding waveguide with respect to the fixed waveguide. An antenna device according to claim 4 ,
A radar device that performs detection based on a signal radiated from the antenna device and a signal received by the antenna device.

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