Patent Application
20240421502
The present application claims priority based on Japanese Patent Application No. 2023-096930 filed to Japanese Patent Office on Jun. 13, 2023, and the content of Japanese Patent Application No. 2023-096930 is incorporated by reference in its entirety.
The present disclosure relates to an antenna radiating element and an antenna device.
JP 2009-10471 A discloses a bow-tie antenna. When arranged in a cross shape, two bow-tie antennas can be arranged in a space-saving manner as antenna elements having orthogonal polarization.
In one aspect of the present disclosure, it is preferable to provide an antenna radiating element and an antenna device that can suppress a deviation in a beam width.
One aspect of the present disclosure is an antenna radiating element including: an antenna portion including two bow-tie antennas arranged in a cross shape; and a reflector. The reflector includes a tubular portion having a cross-sectional shape, which is a regular octagon, in a cross-section orthogonal to an axial direction, a bottom portion closing one end part in the axial direction of the tubular portion, and an opening portion provided at an end part opposite to the one end part of the tubular portion. The antenna portion is positioned in the vicinity of the opening portion.
The antenna radiating element that is one aspect of the present disclosure can suppress a deviation in a beam width.
Embodiments of the present disclosure will be described below with reference to the accompanying drawings, in which:
A configuration of an antenna device 1 will be described with reference to
As shown in
The antenna device 1 includes fittings 21a and 21b. The antenna device 1 is attached to an antenna tower or the like with the fittings 21a and 21b such that a longitudinal direction of the antenna device 1 coincides with the vertical direction.
The antenna device 1 includes coaxial cable adapters 25a and 25b. The coaxial cable adapters 25a and 25b function as radio-frequency signal transmission/reception terminals. The coaxial cable adapters 25a and 25b protrude outward from the antenna cap 23b. As shown in
The antenna device 1 includes a bottom plate 31 inside the radome 22. The plurality of antenna radiating elements 4 are arranged in a row on the bottom plate 31. Both sides in a width direction of the bottom plate 31 are provided with side plates 34a and 34b, respectively. The width direction is a direction orthogonal to the longitudinal direction of the antenna device 1. The bottom plate 31 has a function as a reflector that reflects electromagnetic waves radiated from the antenna radiating elements 4.
The configuration of the antenna radiating element 4 will be described with reference to
The radiating elements 45A, 45B, 45C, and 45D are conductor patterns formed on a main surface on the side of the direction Z1 shown in
The radiating elements 45A, 45B, 45C, and 45D are arranged so as to surround a center 47 of the board 43. The center 47 is a center when viewed from the direction Z1. The radiating element 45A extends from the center 47 in a direction X1 shown in
The radiating element 45B extends from the center 47 in a direction X2 shown in
Each of the radiating elements 45A, 45B, 45C, and 45D has an isosceles triangle shape. In the isosceles triangle, a vertex in between two sides of equal length is on the center 47 side.
The radiating elements 45A and 45B constitute one bow-tie antenna 46. The radiating elements 45C and 45D constitute one bow-tie antenna 48. The bow-tie antenna 46 and the bow-tie antenna 48 are arranged in a cross shape when viewed from the direction Z1. The center 47 is an intersection of the bow-tie antenna 46 and the bow-tie antenna 48. The directions X1 and X2 are extension directions and feed directions of the bow-tie antenna 46. The directions Y1 and Y2 are extension directions and feed directions of the bow-tie antenna 48.
The antenna portion 41 includes through-holes 49A, 49B, 49C, and 49D. Each of the through-holes 49A, 49B, 49C, and 49D penetrates the antenna portion 41 in the thickness direction. The through-hole 49A is formed at a position on the side of the center 47 in the radiating element 45A. The shape of the through-hole 49A is an elongated shape having a longitudinal direction coinciding with the direction X1.
The through-hole 49B is formed at a position on the side of the center 47 in the radiating element 45B. The shape of the through-hole 49B is an elongated shape having a longitudinal direction coinciding with the direction X2. The through-hole 49C is formed at a position on the side of the center 47 in the radiating element 45C. The shape of the through-hole 49C is an elongated shape having a longitudinal direction coinciding with the direction Y1. The through-hole 49D is formed at a position on the side of the center 47 in the radiating element 45D. The shape of the through-hole 49D is an elongated shape having a longitudinal direction coinciding with the direction Y2.
As shown in
The unit substrate 53A is a plate-shape portion extending in the direction X1 from a center 57 of the dielectric substrate 51 when viewed from the direction Z1. The center 57 is a center when viewed from the direction Z1. When viewed from the direction Z1, the center 57 coincides with the center 47 of the antenna portion 41. The unit substrate 53A extends from the center 57 to the outer peripheral side of the antenna portion 41 when viewed from the direction Z1.
The thickness direction of the unit substrate 53A is parallel to the direction Y1 and the direction Y2. The basic form of the unit substrate 53A is a rectangle. The unit substrate 53A includes a protrusion portion 59A on the side of the direction Z1 and the side of the center 57. The protrusion portion 59A protrudes in the direction Z1. The shape of the protrusion portion 59A is a rectangle.
The unit substrate 53B is a plate-shape portion extending in the direction X2 from the center 57 when viewed from the direction Z1. The unit substrate 53B extends from the center 57 to the outer peripheral side of the antenna portion 41 when viewed from the direction Z1. The thickness direction of the unit substrate 53B is parallel to the direction Y1 and the direction Y2. The basic form of the unit substrate 53B is a rectangle. The unit substrate 53B includes a protrusion portion 59B on the side of the direction Z1 and the side of the center 57. The protrusion portion 59B protrudes in the direction Z1. The shape of the protrusion portion 59B is a rectangle.
The unit substrate 53C is a plate-shape portion extending in the direction Y1 from the center 57 when viewed from the direction Z1. The unit substrate 53C extends from the center 57 to the outer peripheral side of the antenna portion 41 when viewed from the direction Z1. The thickness direction of the unit substrate 53C is parallel to the direction X1 and the direction X2. The basic form of the unit substrate 53C is a rectangle. The unit substrate 53C includes a protrusion portion 59C on the side of the direction Z1 and the side of the center 57. The protrusion portion 59C protrudes in the direction Z1. The shape of the protrusion portion 59C is a rectangle.
The unit substrate 53D is a plate-shape portion extending in the direction Y2 from the center 57 when viewed from the direction Z1. The unit substrate 53D extends from the center 57 to the outer peripheral side of the antenna portion 41 when viewed from the direction Z1. The thickness direction of the unit substrate 53D is parallel to the direction X1 and the direction X2. The basic form of the unit substrate 53D is a rectangle. The unit substrate 53D includes a protrusion portion 59D on the side of the direction Z1 and the side of the center 57. The protrusion portion 59D protrudes in the direction Z1. The shape of the protrusion portion 59D is a rectangle.
As shown in
As shown in
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The conductor pattern 61, the unit substrate 53C, and the conductor pattern 83 constitute a microstrip line. The conductor pattern 61 is a conductor pattern for signal transmission. The conductor pattern 83 is a conductor pattern for GND.
The conductor pattern 63, the unit substrate 53A, and the conductor pattern 85 constitute a microstrip line. The conductor pattern 63 is a conductor pattern for signal transmission. The conductor pattern 85 is a conductor pattern for GND.
The unit substrate 53B and the conductor pattern 63 function as a balance-unbalance converter. The unit substrate 53D and the conductor pattern 61 function as a balance-unbalance converter. The function of the balance-unbalance converter is to maintain balance of equilibrium between the microstrip line that is an unbalanced circuit and the radiating elements 45A, 45B, 45C, and 45D that are balanced circuits, and to suppress generation of common mode noise from the microstrip line.
As shown in
As shown in
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As shown in
The tubular portion 97 includes an opening portion 96 at an end part on the side of the direction Z1. The outside and the inside of the tubular portion 97 communicate with each other via the opening portion 96. The size of the opening portion 96 is equal to the size of a hole inside the tubular portion 97. An end part on the side of the direction Z2 in the tubular portion 97 is closed by the bottom portion 55. The tubular portion 97 and the bottom portion 55 constitute the reflector 98.
As shown in
As shown in
A radio-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. A radio-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.
The dielectric substrate 51 can be manufactured by injection molding, for example. The conductor patterns 61, 63, 83, and 85 can be formed by a molded interconnected device (MID) technology, for example.
(1A) By including the reflector 98, the antenna radiating element 4 can suppress a deviation of the beam width. The effect of being able to suppress the deviation of the beam width could be confirmed using simulation software (Femlet manufactured by Murata Software Co., Ltd.).
(1B) The shape of the reflector 98 in a cross section orthogonal to the direction Z1 is a regular octagon. This enables the plurality of antenna radiating elements 4 to be densely arrayed. Densely arraying the antenna radiating elements 4 can downsize the antenna device 1. This effect will be described with reference to
In the cross section orthogonal to the direction Z1, assume that a distance between two opposing sides of the reflector 98 having a regular octagonal shape is L. Assume that each side of the reflector 98 having a regular octagonal shape is 98A. In the state shown in
If the shape of the reflector 98 in the cross section orthogonal to the direction Z1 is a square whose length of one side is L, a corner region 101 shown in
(1C) The shape of the reflector 98 in the cross section orthogonal to the direction Z1 is a regular octagon. Assume that 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 as compared with a case where the shape of the reflector 98 in the cross section orthogonal to the direction Z1 is a circle having a diameter L. This can further suppress the deviation of the beam width.
(1D) The shape of the reflector 98 in the cross section orthogonal to the direction Z1 is a regular octagon. Therefore, as shown in
(1E) The center axis 99 of the tubular portion 97 passes through an intersection (i.e., the center 47) of the bow-tie antenna 46 and the bow-tie antenna 48. The center axis 99 and the extension direction (i.e., the directions X1 and X2) of the bow-tie antenna 46 are orthogonal to each other. The center axis 99 and the extension direction (i.e., the directions Y1 and Y2) of the bow-tie antenna 48 are orthogonal to each other. Due to this, the effect of the reflector 98 is further enhanced, and the antenna radiating element 4 can further suppress the deviation of the beam width.
Although an embodiment of the present disclosure has been described above, the present disclosure is not limited to the above-described embodiment, and can be carried out in various modifications.
(1) In the first embodiment, the reflector 98 may include a body portion made of resin and/or containing resin, and a metal plated layer formed on a surface of the body portion. Also in this case, effects similar to those of the first embodiment can be achieved.
(2) The function of one constituent element in each of the above embodiments may be shared by a plurality of constituent elements, or the function of a plurality of constituent elements may be exerted by one constituent element. A part of the configuration of each of the above embodiments may be omitted. At least a part of the configuration of each of the above embodiments may be added to, replaced with, or the like, the configuration of another of the above embodiments.
(3) In addition to the antenna radiating element 4 described above, the present disclosure can be implemented in various forms such as a system including the antenna radiating element 4 as a constituent element and a manufacturing method of the antenna radiating element 4.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023096930 | Jun 2023 | JP | national |
