Radiation element for antenna and antenna device

Abstract

To provide a radiation element for an antenna, capable of suppressing deflection of a beam width, and provide an antenna device.SOLUTION: A radiation element for an antenna, comprises an antenna part and a reflection plate. The antenna part comprises two bow tie antennas arranged so as to be in a cross shape. The reflection plate comprises: a cylinder part of which a cross sectional shape in a cross section orthogonal to a shaft direction is a regular octagon; a bottom part that blocks one end part in the shaft direction of the cylinder part; and an open part that is provided to an end part that is opposite to the one end part of the cylinder part. The antenna part is positioned near the open part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a radiating element for an antenna and an antenna device. [Background technology]

[0002] A bowtie antenna is disclosed in Patent Document 1. When two bowtie antennas are arranged in a cross shape, they can be arranged in a space-saving manner as antenna elements having orthogonal polarizations. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-10471 A Summary of the Invention [Problem to be solved by the invention]

[0004] 11 shows an element direction D1, which is the power feeding direction, and a vertical direction D2 perpendicular to the element direction D1 in a bow-tie antenna 201. A problem occurs in the bow-tie antenna 201 in that there is a large difference between the beam width in the element direction D1 and the beam width in the vertical direction D2 (hereinafter referred to as the beam width deviation).

[0005] In one aspect of the present disclosure, it is preferable to provide an antenna radiating element and an antenna device capable of suppressing deviation in beam width. [Means for solving the problem]

[0006] One aspect of the present disclosure is an antenna radiating element including an antenna unit including two bowtie antennas arranged in a cross shape, and a reflector. The reflector includes a cylindrical portion having a regular octagonal cross section perpendicular to the axial direction, a bottom portion closing one end of the cylindrical portion in the axial direction, and an opening portion provided at the end opposite the one end of the cylindrical portion. The antenna unit is located near the opening portion.

[0007] A radiating element for an antenna according to one aspect of the present disclosure can suppress deviation of beam width. [Brief description of the drawings]

[0008] [Figure 1] Fig. 1A is a perspective view showing the external appearance of an antenna device, and Fig. 1B is a perspective view showing a plurality of antenna radiating elements arranged inside the antenna device. [Diagram 2] FIG. 2 is a perspective view illustrating a configuration of a radiating element for an antenna. [Diagram 3] 2 is an explanatory diagram showing an antenna radiating element as viewed from a direction Z1. FIG. [Figure 4] FIG. 2 is a perspective view showing the configuration of an antenna radiating element with the antenna portion removed. [Diagram 5] FIG. 2 is a perspective view showing the configuration of an antenna radiating element with the antenna portion removed. [Figure 6] FIG. 2 is a perspective view showing the configuration of an antenna radiating element with the antenna portion removed. [Figure 7] FIG. 2 is a perspective view showing the configuration of an antenna radiating element with the antenna portion removed. [Figure 8] 4 is a perspective view showing the configuration of an antenna radiating element with a cylindrical portion removed. FIG. [Figure 9] 1 is an explanatory diagram showing a state in which a plurality of antenna radiating elements are arranged in a staggered pattern. [Figure 10] FIG. 4 is an explanatory diagram showing the position of an antenna unit relative to a reflector. [Figure 11]FIG. 2 is an explanatory diagram showing the element direction and vertical direction in a bowtie antenna. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Exemplary embodiments of the present disclosure will now be described with reference to the drawings. First Embodiment 1. Configuration of Antenna Device 1 The configuration of antenna device 1 will be described with reference to Figures 1A and 1B. Note that in Figure 1B, the antenna section 41 and reflector 98, which are parts of antenna radiating element 4, are omitted. Antenna device 1 is used as an antenna device for a mobile phone base station, for example.

[0010] 1A, the antenna device 1 includes a cylindrical radome 22 and antenna caps 23a and 23b. Both ends of the radome 22 are closed by the antenna caps 23a and 23b.

[0011] The antenna device 1 includes mounting brackets 21a and 21b. The antenna device 1 is attached to an antenna tower or the like by the mounting brackets 21a and 21b so that the longitudinal direction of the antenna device 1 is aligned vertically. The antenna device 1 includes coaxial cable adapters 25a and 25b. The coaxial cable adapters 25a and 25b function as high-frequency signal transmitting / receiving terminals. The coaxial cable adapters 25a and 25b protrude from the antenna cap 23b to the outside. As shown in FIG. 1B, the antenna device 1 includes a plurality of antenna radiating elements 4. The plurality of antenna radiating elements 4 are housed inside the radome 22.

[0012] The antenna device 1 includes a bottom plate 31 inside the radome 22. A plurality of antenna radiating elements 4 are arranged in a row on the bottom plate 31. Side plates 34a, 34b are provided on both sides of the bottom plate 31 in the width direction. The width direction is a direction perpendicular to the longitudinal direction of the antenna device 1. The bottom plate 31 functions as a reflector that reflects electromagnetic waves radiated from the antenna radiating elements 4.

[0013] 2. Configuration of antenna radiating element 4 The configuration of antenna radiating element 4 will be described with reference to Figures 2 to 8. As shown in Figures 2 and 3, antenna radiating element 4 includes antenna section 41. Antenna section 41 includes substrate 43 and four radiating elements 45A, 45B, 45C, and 45D. Substrate 43 is a regular octagonal plate made of a dielectric material.

[0014] Radiating elements 45A, 45B, 45C, and 45D are conductor patterns formed on the principal surface of substrate 43 on the side of direction Z1 shown in Fig. 2. The principal surface is a surface of a plate-like member that has a much larger area than the other surfaces. Direction Z1 is parallel to the thickness direction of substrate 43.

[0015] Radiating elements 45A, 45B, 45C, and 45D are arranged to surround center 47 of substrate 43. Center 47 is the center when viewed from direction Z1. Radiating element 45A extends from center 47 in direction X1 shown in Fig. 3. Direction X1 is parallel to the main surface of substrate 43 and perpendicular to direction Z1.

[0016] The radiating element 45B extends from the center 47 in the direction X2 shown in FIG. 3. The direction X2 is the opposite direction to the direction X1. The radiating element 45C extends from the center 47 in the direction Y1 shown in FIG. 3. The direction Y1 is parallel to the main surface of the substrate 43 and is perpendicular to the directions Z1, X1, and X2. The radiating element 45D extends from the center 47 in the direction Y2 shown in FIG. 3. The direction Y2 is the opposite direction to the direction Y1.

[0017] The shape of each of the radiating elements 45A, 45B, 45C, and 45D is an isosceles triangle. In the isosceles triangle, the apex between two sides of equal length is on the center 47 side. The radiating elements 45A and 45B constitute one bowtie antenna 46. The radiating elements 45C and 45D constitute one bowtie antenna 48. The bowtie antennas 46 and 48 are arranged to form a cross shape when viewed from the direction Z1. The center 47 is the intersection of the bowtie antennas 46 and 48. The directions X1 and X2 are the extension direction and power feeding direction of the bowtie antenna 46. The directions Y1 and Y2 are the extension direction and power feeding direction of the bowtie antenna 48.

[0018] The antenna unit 41 includes through holes 49A, 49B, 49C, and 49D. The through holes 49A, 49B, 49C, and 49D each penetrate the antenna unit 41 in the thickness direction. The through hole 49A is formed in a position on the center 47 side of the radiating element 45A. The shape of the through hole 49A is an elongated shape with the direction X1 as the longitudinal direction.

[0019] The through hole 49B is formed in a position on the center 47 side of the radiating element 45B. The through hole 49B has an elongated shape with the direction X2 as its longitudinal direction. The through hole 49C is formed in a position on the center 47 side of the radiating element 45C. The through hole 49C has an elongated shape with the direction Y1 as its longitudinal direction. The through hole 49D is formed in a position on the center 47 side of the radiating element 45D. The through hole 49D has an elongated shape with the direction Y2 as its longitudinal direction.

[0020] As shown in Figures 2 and 4 to 8, the antenna radiating element 4 includes a dielectric substrate 51. The dielectric substrate 51 is on the direction Z2 side with respect to the antenna portion 41. The direction Z2 is the opposite direction to the direction Z1. The dielectric substrate 51 contacts the main surface of the antenna portion 41 on the direction Z2 side. As shown in Figures 4 to 7, the dielectric substrate 51 includes unit substrates 53A, 53B, 53C, and 53D.

[0021] Unit substrate 53A is a plate-shaped portion extending in direction X1 from center 57 of dielectric substrate 51 when viewed from direction Z1. Center 57 is the center when viewed from direction Z1. When viewed from direction Z1, center 57 coincides with center 47 of antenna portion 41. Furthermore, unit substrate 53A extends from center 57 to the outer periphery of antenna portion 41 when viewed from direction Z1.

[0022] The thickness direction of unit substrate 53A is parallel to direction Y1 and direction Y2. Unit substrate 53A is basically rectangular in shape. Unit substrate 53A has a protrusion 59A on the direction Z1 side and on the center 57 side. Protrusion 59A protrudes in direction Z1. Protrusion 59A has a rectangular shape.

[0023] When viewed from direction Z1, unit substrate 53B is a plate-shaped portion extending from center 57 in direction X2. When viewed from direction Z1, unit substrate 53B extends from center 57 toward the outer periphery of antenna portion 41. The thickness direction of unit substrate 53B is parallel to directions Y1 and Y2. Unit substrate 53B is basically rectangular. Unit substrate 53B has a protrusion 59B on the side of direction Z1 and center 57. Protrusion 59B protrudes in direction Z1. Protrusion 59B is rectangular in shape.

[0024] When viewed from direction Z1, unit substrate 53C is a plate-shaped portion extending from center 57 in direction Y1. When viewed from direction Z1, unit substrate 53C extends from center 57 to the outer periphery of antenna portion 41. The thickness direction of unit substrate 53C is parallel to directions X1 and X2. Unit substrate 53C is basically rectangular. Unit substrate 53C has a protrusion 59C on the side of direction Z1 and center 57. Protrusion 59C protrudes in direction Z1. Protrusion 59C is rectangular in shape.

[0025] When viewed from direction Z1, unit substrate 53D is a plate-shaped portion extending from center 57 in direction Y2. When viewed from direction Z1, unit substrate 53D extends from center 57 toward the outer periphery of antenna portion 41. The thickness direction of unit substrate 53D is parallel to directions X1 and X2. Unit substrate 53D is basically rectangular in shape. Unit substrate 53D has a protrusion 59D on the side of direction Z1 and center 57. Protrusion 59D protrudes in direction Z1. Protrusion 59D is rectangular in shape.

[0026] 4 to 7, when viewed from direction Z1, unit substrates 53A and 53B are aligned on a straight line that passes through center 57 and is parallel to directions X1 and X2. When viewed from direction Z1, unit substrates 53C and 53D are aligned on a straight line that passes through center 57 and is parallel to directions Y1 and Y2.

[0027] As shown in Figures 4 to 8, antenna radiating element 4 has a bottom 55. Dielectric substrate 51 is connected to bottom 55. Bottom 55 is a regular octagonal plate-like member. The size of bottom 55 is equal to the size of substrate 43. Bottom 55 is connected to the side surfaces of unit substrates 53A to 53D on the Z2 side. The side surface is a surface between one main surface and the opposite main surface of a plate-like member. The thickness direction of bottom 55 is parallel to directions Z1 and Z2.

[0028] 6 and 7, a continuous conductor pattern 61 is provided on dielectric substrate 51. Conductive pattern 61 is a conductor pattern for signal transmission. Conductive pattern 61 extends over the surface of unit substrate 53C, the surface of unit substrate 53D, and the surface of protruding portion 59D.

[0029] 5 and 7, a continuous conductor pattern 63 is provided on dielectric substrate 51. Conductive pattern 63 is a conductor pattern for signal transmission. Conductive pattern 63 extends over the surface of unit substrate 53A, through the surface of unit substrate 53B, and to the surface of protruding portion 59B.

[0030] 5 and 6, a continuous conductor pattern 83 is provided on dielectric substrate 51. Conductive pattern 83 is a conductor pattern for GND. Conductive pattern 83 extends over the surface of unit substrate 53C and reaches the surface of protruding portion 59C.

[0031] 6, a continuous conductor pattern 85 is provided on dielectric substrate 51. Conductive pattern 85 is a conductor pattern for GND. Conductive pattern 85 extends over the surface of unit substrate 53A and reaches the surface of protruding portion 59A.

[0032] A microstrip line is formed by conductor pattern 61, unit substrate 53C, and conductor pattern 83. Conductive pattern 61 is a conductor pattern for signal transmission. Conductive pattern 83 is a conductor pattern for GND.

[0033] A microstrip line is formed by conductor pattern 63, unit substrate 53A, and conductor pattern 85. Conductive pattern 63 is a conductor pattern for signal transmission. Conductive pattern 85 is a conductor pattern for GND.

[0034] Unit substrate 53B and conductor pattern 63 function as a balanced-unbalanced converter. Unit substrate 53D and conductor pattern 61 function as a balanced-unbalanced converter. The function of the balanced-unbalanced converter is to maintain a balance between the microstrip line, which is an unbalanced circuit, and radiating elements 45A, 45B, 45C, and 45D, which are balanced circuits, and to suppress the generation of common mode noise from the microstrip line.

[0035] 2, 3, and 8, the protrusion 59A is inserted into the through hole 49A. The tip of the protrusion 59A is closer to the direction Z1 than the antenna portion 41. A part of the conductor pattern 85 formed on the protrusion 59A is closer to the direction Z1 than the antenna portion 41. The part of the conductor pattern 85 formed on the protrusion 59A is connected to the radiating element 45A by soldering.

[0036] 2, 3, and 8, the protrusion 59B is inserted into the through hole 49B. The tip of the protrusion 59B is closer to the direction Z1 than the antenna portion 41. A part of the conductor pattern 63 formed on the protrusion 59B is closer to the direction Z1 than the antenna portion 41. The part of the conductor pattern 63 formed on the protrusion 59B is connected to the radiating element 45B by soldering.

[0037] 2, 3, and 8, the protrusion 59C is inserted into the through hole 49C. The tip of the protrusion 59C is closer to the direction Z1 than the antenna portion 41. A part of the conductor pattern 83 formed on the protrusion 59C is closer to the direction Z1 than the antenna portion 41. The part of the conductor pattern 83 formed on the protrusion 59C is connected to the radiating element 45C by soldering.

[0038] 2, 3, and 8, the protrusion 59D is inserted into the through hole 49D. The tip of the protrusion 59D is closer to the direction Z1 than the antenna portion 41. A part of the conductor pattern 63 formed on the protrusion 59D is closer to the direction Z1 than the antenna portion 41. The part of the conductor pattern 63 formed on the protrusion 59D is connected to the radiating element 45D by soldering.

[0039] As shown in Figures 2 to 7, the antenna radiating element 4 includes a hollow cylindrical portion 97. The axial direction of the cylindrical portion 97 is parallel to the direction Z1 and the direction Z2. The cross-sectional shape of the cylindrical portion 97 in a cross section perpendicular to the direction Z1 and the direction Z2 is a regular octagon. The central axis 99 of the cylindrical portion 97 shown in Figure 3 is parallel to the direction Z1 and the direction Z2 and passes through the center 47. The central axis 99 is a straight line that passes through the center of the cylindrical portion 97 in a cross section perpendicular to the direction Z1 and the direction Z2 and is parallel to the direction Z1 and the direction Z2.

[0040] The cylindrical portion 97 has an opening 96 at its end in direction Z1. The outside and inside of the cylindrical portion 97 are in communication with each other via the opening 96. The size of the opening 96 is equal to the size of the hole inside the cylindrical portion 97. The end of the cylindrical portion 97 in direction Z2 is closed by the bottom portion 55. The cylindrical portion 97 and the bottom portion 55 form a reflecting plate 98.

[0041] As shown in FIG. 2, the antenna section 41 is located near the opening 96 and outside the reflector 98. The antenna section 41 is located on the direction Z1 side of the opening 96. In the direction Z1, a gap exists between the antenna section 41 and the reflector 98. As shown in FIG. 10, the distance in the direction Z1 between the end 97A of the cylindrical section 97 on the direction Z1 side and the antenna section 41 is defined as L1. L1 is preferably, for example, λ / 6 or more and λ / 10 or less. λ is a wavelength corresponding to the resonance frequency of the antenna radiating element 4. As shown in FIG. 10, the distance in the direction Z1 between the bottom 55 and the antenna section 41 is defined as L2. L2 is preferably about λ / 4.

[0042] 2 and 4 to 7, most of the dielectric substrate 51 is housed inside the cylindrical portion 97. The reflector 98 (i.e., the cylindrical portion 97 and the bottom portion 55) is a member made of a metal such as aluminum. The high frequency signal received by the coaxial cable adapter 25a is sent to the radiating element 45D via an intermediate path (not shown) and the conductor pattern 61. The high frequency signal received by the coaxial cable adapter 25b is sent to the radiating element 45B via an intermediate path (not shown) and the conductor pattern 63.

[0043] The dielectric substrate 51 can be manufactured by, for example, injection molding. The conductor patterns 61, 63, 81, and 83 can be formed by, for example, MID (Molded Interconnected Device) technology.

[0044] 3. Effects of the antenna radiating element 4 (1A) The antenna radiating element 4 can suppress deviations in beam width by providing the reflector 98. The effect of suppressing deviations in beam width was confirmed using simulation software (Femlet, manufactured by Murata Software).

[0045] (1B) The shape of the reflector 98 in a cross section perpendicular to direction Z1 is a regular octagon. This allows multiple antenna radiating elements 4 to be densely arranged. By densely arranging the antenna radiating elements 4, the antenna device 1 can be made smaller. This effect will be explained with reference to FIG. 9. FIG. 9 shows a state in which multiple antenna radiating elements 4 are arranged in a staggered pattern. Note that the multiple antenna radiating elements 4 may be arranged along a single straight line as shown in FIG. 1, or may be arranged as shown in FIG. 9.

[0046] In a cross section perpendicular to direction Z1, the distance between two opposing sides of a regular octagonal reflector 98 is designated as L. Each side of the regular octagonal reflector 98 is designated as 98A. In the state shown in Fig. 9, the sides 98A of adjacent antenna radiating elements 4 face each other with a short distance between them.

[0047] If the shape of the reflector 98 in a cross section perpendicular to direction Z1 is a square with a side length of L, then corner areas 101 of the reflector 98 shown in Fig. 9 will overlap and be included in both reflectors 98 of adjacent antenna radiating elements 4. Therefore, the distance between adjacent antenna radiating elements 4 must be made larger than the distance shown in Fig. 9. As a result, when the shape of the reflector 98 is a square, the antenna radiating elements 4 cannot be arranged more densely than when the shape of the reflector 98 is a regular octagon.

[0048] (1C) The shape of the reflector 98 in a cross section perpendicular to the direction Z1 is a regular octagon. The distance between two opposing sides of the regular octagon is L. In this case, the cross-sectional area of ​​the reflector 98 can be made larger than when the shape of the reflector 98 in a cross section perpendicular to the direction Z1 is a circle with a diameter L. This makes it possible to further suppress deviations in the beam width.

[0049] (1D) The shape of the reflector 98 in a cross section perpendicular to the direction Z1 is a regular octagon. Therefore, as shown in Fig. 9, by arranging the sides 98A of the regular octagons facing each other between the multiple antenna radiating elements 4, it is easy to regularly arrange the multiple antenna radiating elements 4. However, if the shape of the reflector 98 in a cross section perpendicular to the direction Z1 is circular, there is no side 98A to serve as a reference for the arrangement, making it difficult to regularly arrange the multiple antenna radiating elements 4.

[0050] (1E) Central axis 99 of cylindrical portion 97 passes through the intersection (i.e., center 47) between bowtie antenna 46 and bowtie antenna 48. Central axis 99 is also perpendicular to the extension direction (i.e., directions X1 and X2) of bowtie antenna 46. Central axis 99 is also perpendicular to the extension direction (i.e., directions Y1 and Y2) of bowtie antenna 48. Therefore, the effect of reflector 98 is further increased, and antenna radiating element 4 can further suppress deviation in beam width. <Other embodiments> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms.

[0051] (1) In the first embodiment, the reflector 98 may include a body made of resin and a metal plating layer formed on the surface of the body. In this case, the same effects as in the first embodiment can be achieved.

[0052] (2) The function of one component in each of the above embodiments may be shared by multiple components, or the functions of multiple components may be performed by one component. Also, part of the configuration of each of the above embodiments may be omitted. Also, at least part of the configuration of each of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0053] (3) In addition to the above-described antenna radiating element 4, the present disclosure can be realized in various forms, such as a system including the antenna radiating element 4 as a component, and a method for manufacturing the antenna radiating element 4.

[0054] [Technical idea disclosed in this specification] [Item 1] an antenna unit including two bowtie antennas arranged in a cross shape; A reflector and Equipped with The reflector is A cylindrical portion having a regular octagonal cross-sectional shape in a cross section perpendicular to the axial direction; a bottom portion that closes one end of the cylindrical portion in the axial direction; an opening provided at an end portion of the cylindrical portion opposite the one end; Equipped with The antenna portion is located near the opening. Radiating element for antenna. [Item 2] A radiating element for an antenna according to item 1, The central axis of the cylindrical portion passes through the intersection of the two bowtie antennas, The central axis and the extension direction of the two bowtie antennas are perpendicular to each other. Radiating element for antenna. [Item 3] A radiating element for an antenna according to item 1 or 2, The reflector is A main body made of resin; A metal plating layer formed on the surface of the main body portion; Equipped with Radiating element for antenna. [Item 4] An antenna device comprising the radiating element for an antenna according to any one of items 1 to 3. [Explanation of symbols]

[0055] 1...antenna device, 4...radiating element for antenna, 21a...mounting bracket, 22...radome, 23a, 23b...antenna cap, 25a, 25b...coaxial cable adapter, 31...bottom plate, 34a...side plate, 41...antenna section, 43...substrate, 45A, 45B, 45C, 45D...radiating element, 46, 48...bow-tie antenna, 47...center, 49A, 49B, 49C, 49D...through hole, 51...dielectric substrate, 53A, 53B, 53C, 53D...unit substrate, 55...bottom, 57...center, 59A, 59B, 59C, 59D...projection, 61, 63, 83, 85...conductor pattern, 96...opening, 97...cylindrical portion, 98...reflector, 98A...side, 99...center axis, 101...area

Claims

1. an antenna unit including two bowtie antennas arranged in a cross shape; A reflector and Equipped with The reflector is A cylindrical portion having a regular octagonal cross-sectional shape in a cross section perpendicular to the axial direction; a bottom portion that closes one end of the cylindrical portion in the axial direction; an opening provided at an end portion of the cylindrical portion opposite the one end; Equipped with The antenna portion is located near the opening. Radiating element for antenna.

2. 2. A radiating element for an antenna according to claim 1, a central axis of the cylindrical portion passes through an intersection of the two bowtie antennas, The central axis and the extension direction of the two bowtie antennas are perpendicular to each other. Radiating element for antenna.

3. A radiating element for an antenna according to claim 1 or 2, The reflector is A main body made of resin; A metal plating layer formed on the surface of the main body portion; Equipped with Radiating element for antenna.

4. An antenna device comprising the radiating element for an antenna according to claim 1 or 2.

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