Antenna device

Abstract

To provide an antenna device which has a compact configuration and is compatible with electric waves in wide bandwidth.SOLUTION: An antenna device comprises: a cylindrical conductor; and a plate-like conductor which is disposed on at least one end in an axial direction of the cylindrical conductor and extends in an intersecting direction that intersects the axial direction. Further, the cylindrical conductor has: a slot which is formed on a portion along a circumferential direction of the cylindrical conductor and extends in the intersecting direction; and a power feeding part which feeds power to the slot. Furthermore, the antenna device has a non-feeding conductor which is located in an inner region of the cylindrical conductor when viewed from the axial direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an antenna device. [Background technology]

[0002] Conventionally, antenna devices have been mounted on mobile bodies such as automobiles, buses, railway vehicles, etc. For example, an omnidirectional mobile body antenna is known that includes a cylindrical body with a notch formed in the circumferential direction, both made of a conductive material, and end plates that are fixed to both ends of the cylindrical body and have a diameter larger than that of the cylindrical body (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-136627 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, radio waves in multiple frequency bands are used, for example, in telephone and data communications. To meet the demand for multimedia, antenna devices for mobile devices are also required to be compatible with wideband radio waves. Furthermore, miniaturization of antenna devices for installation on mobile devices has been an issue.

[0005] In view of the above-mentioned problems, an object of the present invention is to provide an antenna device that has a compact configuration and is capable of handling radio waves over a wide band. [Means for solving the problem]

[0006] An exemplary antenna device of the present invention includes a cylindrical conductor, a flat conductor disposed at at least one axial end of the cylindrical conductor and extending in a direction intersecting the axial direction, the cylindrical conductor further includes a slot formed in a portion of the cylindrical conductor along a circumferential direction and extending in the intersecting direction, and a power supply portion for supplying power to the slot, and the antenna device further includes a parasitic conductor located in an inner region of the cylindrical conductor as viewed from the axial direction. [Effects of the Invention]

[0007] According to the configuration of the present invention, the antenna device can be made compact and can handle radio waves over a wide band. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic perspective view of an antenna device according to a first embodiment; [Figure 2] 2 is a perspective view of the antenna device of FIG. 1 as seen from below; [Figure 3] A side view of the antenna device of FIG. 1 [Figure 4] Plan view of the antenna device of Figure 1 [Figure 5] 4 is a cross-sectional view of the antenna device of FIG. 3 taken along line VV. [Figure 6] FIG. 10 is a schematic perspective view of an antenna device according to a second embodiment. [Figure 7] 7 is a perspective view of the antenna device of FIG. 6 as seen from below. [Figure 8] FIG. 7 is a plan view of the antenna device of FIG. [Figure 9] FIG. 10 is a schematic perspective view of an antenna device according to a third embodiment. [Figure 10] FIG. 10 is a schematic perspective view of an antenna device according to a fourth embodiment. [Figure 11] FIG. 10 is a schematic perspective view of an antenna device according to a fifth embodiment. [Figure 12] 12 is a side view of the antenna device of FIG. 11. [Figure 13] FIG. 10 is a schematic perspective view of an antenna device according to a sixth embodiment. [Figure 14] 14 is a side view of the antenna device of FIG. 13. [Figure 15] FIG. 13 is a schematic perspective view of an antenna device according to a seventh embodiment. [Figure 16] 16 is a side view of the antenna device of FIG. 15. [Figure 17] FIG. 13 is a schematic perspective view of an antenna device according to an eighth embodiment. [Figure 18] 18 is a side view of the antenna device of FIG. 17. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In this description, the direction in which a cylindrical conductor (described later) extends is referred to as the "axial direction," and an arrow Dz representing this axial direction is shown in the drawings. Furthermore, arrows Dx and Dy representing a Cartesian coordinate system are shown in the drawings with respect to the axial direction Dz. Furthermore, a direction intersecting with the axial direction Dz is called the "intersecting direction." The intersecting direction includes a direction perpendicular to the axial direction Dz, and is referred to as the "intersecting direction Dx-Dy" in this description, but is not limited to being strictly perpendicular and also includes being approximately perpendicular.

[0010] 1. First Embodiment FIG. 1 is a schematic perspective view of the antenna device 1 of the first embodiment. FIG. 2 is a perspective view of the antenna device 1 of FIG. 1 as seen from below. FIGS. 3 and 4 are a side view and a plan view of the antenna device 1 of FIG. 1. FIG. 5 is a cross-sectional view of the antenna device of FIG. 1 taken along line VV. Note that a feeder line 102, which will be described later, is omitted from FIGS. 1, 2, 3, and 4. A printed circuit board 101, which will be described later, is omitted from FIG. 2.

[0011] The antenna device 1 is preferably mounted on a vehicle such as an automobile, but may also be mounted on a moving body other than a vehicle. Examples of moving bodies other than a vehicle include ships, aircraft, and robots. The antenna device 1 may also be mounted on something other than a moving body. In this embodiment, the antenna device 1 is an in-vehicle antenna device.

[0012] As shown in FIG. 1, the antenna device 1 includes a tubular conductor 2A, flat conductors 3A and 3B, and a parasitic conductor 4A.

[0013] The tubular conductor 2A extends in the axial direction Dz. In this embodiment, the tubular conductor 2A has a rectangular tube shape, and its cross section in the intersecting direction Dx-Dy intersecting the axial direction Dz is rectangular. That is, the tubular conductor 2A is composed of four flat peripheral walls 2w extending in the axial direction Dz and arranged in a rectangular cross section. Note that the cross section of the tubular conductor 2A may be another polygonal shape, such as a triangle or a pentagon, or may be cylindrical. Both ends of the tubular conductor 2A in the axial direction Dz are open.

[0014] The "circumferential direction" of the cylindrical conductor 2A, which will be described later, means a direction going back and forth between adjacent peripheral walls 2w with respect to the cross direction Dx-Dy.

[0015] The tubular conductor 2A is made of a metal plate made of a conductive material such as copper or iron. In this embodiment, the antenna device 1 is compatible with one type of electromagnetic wave (radio wave). The antenna device 1 constitutes a transmitting antenna or a receiving antenna. If the wavelength of the electromagnetic wave transmitted or received by the antenna device 1 is λ, then in a preferred embodiment, the length of the tubular conductor 2A in the axial direction Dz may be less than λ / 4. The reason for this is related to the fact that the antenna device 1 includes the flat conductors 3A and 3B, and will be described later. If there is sufficient space in the axial direction Dz for installing the antenna device 1, the length of the tubular conductor 2A in the axial direction Dz may be λ / 4 or more.

[0016] The flat conductor 3A is arranged at one end of the tubular conductor 2A in the axial direction Dz. In this embodiment, the flat conductor 3A is, for example, a conductor pattern formed on one surface of the printed circuit board 101. The flat conductor 3A is joined to the tubular conductor 2A. The flat conductor 3A extends in a transverse direction Dx-Dy that intersects with the axial direction Dz. In this embodiment, the flat conductor 3A extends in a direction perpendicular to the axial direction Dz. The flat conductor 3A is made of a conductive material such as copper or iron. The flat conductor 3A is made of, for example, the same conductive material as the tubular conductor 2A.

[0017] In this embodiment, the flat conductor 3A has a rectangular shape extending outside and inside the tubular conductor 2A in the transverse direction Dx-Dy. In this embodiment, each of the four sides of the outer edge of the rectangular flat conductor 3A extends parallel to one of the four peripheral walls 2w that constitute the tubular conductor 2A. Note that the flat conductor 3A may have another polygonal shape, such as a triangle or a pentagon, or may be circular. In the transverse direction Dx-Dy, the outer edge of the flat conductor 3A is located outside the outer edge of the tubular conductor 2A.

[0018] In this embodiment, the flat conductor 3A is arranged so as to close one end of the tubular conductor 2A in the axial direction Dz. Note that the flat conductor 3A may be configured so as not to extend inward beyond the inner edge of the tubular conductor 2A in the transverse direction Dx-Dy, or may extend inward to a predetermined length. In other words, the flat conductor 3A may be configured so that one end of the tubular conductor 2A is open in the axial direction Dz.

[0019] The flat conductor 3B is disposed at the other end of the tubular conductor 2A in the axial direction Dz. That is, more specifically, the antenna device 1 further includes, in addition to the flat conductor 3A disposed at one end of the tubular conductor 2A in the axial direction Dz, another flat conductor 3B disposed at the other end of the tubular conductor 2A in the axial direction Dz and extending in the transverse direction Dx-Dy. The flat conductor 3B is formed integrally with, for example, the tubular conductor 2A. In other words, the flat conductor 3B is the same member as the tubular conductor 2A and is formed from a sheet metal of a conductive material such as copper or iron.

[0020] In this embodiment, the flat conductor 3B has a rectangular ring-shaped outer shape that extends outside the tubular conductor 2A in the transverse direction Dx-Dy. The flat conductor 3B extends, for example, in a direction perpendicular to the axial direction Dz. In this embodiment, each of the four sides of the rectangular outer edge of the flat conductor 3B extends parallel to one of the four peripheral walls 2w that constitute the tubular conductor 2A. The outer shape of the flat conductor 3B may be another polygonal shape, such as a triangle or a pentagon, or may be a circle. In the transverse direction Dx-Dy, the outer edge of the flat conductor 3B is located outside the outer edge of the tubular conductor 2A.

[0021] In this embodiment, both the flat conductors 3A and 3B have a rectangular outer shape extending in the transverse direction Dx-Dy. The flat conductors 3A and 3B are spaced apart in the axial direction Dz across the tubular conductor 2A and extend parallel to the transverse direction Dx-Dy. The outer shapes and sizes of the flat conductors 3A and 3B may be different from each other or may be the same as each other. Furthermore, the flat conductor 3B may not be provided. In other words, it is sufficient that the flat conductor is disposed at at least one end of the tubular conductor 2A in the axial direction Dz.

[0022] The tubular conductor 2A has a notch 21. The notch 21 is arranged at one end of the tubular conductor 2A in the axial direction Dz facing the flat conductor 3A. The notch 21 is formed in a portion of the tubular conductor 2A along the circumferential direction. The notch 21 is recessed in the tubular conductor 2A toward the other end in the axial direction Dz. In other words, the tubular conductor 2A is joined to the flat conductor 3A at the remaining portion of the tubular conductor 2A along the circumferential direction where the notch 21 is not formed at one end of the axial direction Dz facing the flat conductor 3A. The tubular conductor 2A and the flat conductor 3A may be joined directly or by being inserted into a connector or a slit.

[0023] The notch 21 penetrates the peripheral wall 2w of the tubular conductor 2A in the transverse direction Dx-Dy. The notch 21 defines a slot 5A between the notch 21 and the flat conductor 3A. In this embodiment, the slot 5A is a slot of a so-called slot antenna that has a quadrangular shape when viewed from the transverse direction Dx-Dy. That is, the tubular conductor 2A includes the slot 5A.

[0024] The slots 5A are formed in a portion of the tubular conductor 2A along the circumferential direction and extend in the transverse direction Dx-Dy. The length of the slots 5A (notches 21) along the circumferential direction of the tubular conductor 2A is λ / 2, where λ is the wavelength of the electromagnetic wave. The length (width) of the slots 5A in the axial direction Dz is sufficiently small compared to the wavelength λ. The length (width) of the slots 5A in the axial direction Dz is, for example, λ / 100.

[0025] The length of the slot 5A is λ / 2, and the circumferential length of the tubular conductor 2A itself is preferably between λ / 2 and 2λ / 3. The circumferential length of the flat conductor 3A is preferably approximately [the circumferential length of the tubular conductor 2A itself] × 7 / 5.

[0026] The slot 5A is not limited to a rectangular shape when viewed from the cross direction Dx-Dy. For example, the slot 5A may have a shape in which both ends in the cross direction Dx-Dy extend in the axial direction Dz, or both ends in the cross direction Dx-Dy bend in a hook shape in the axial direction Dz and the cross direction Dx-Dy. This allows the wavelength λ of the electromagnetic waves transmitted or received by the antenna device 1 to be longer.

[0027] The antenna device 1 further includes a power supply portion 22. The power supply portion 22 is formed by a part of the tubular conductor 2A. The power supply portion 22 extends continuously from one peripheral wall 2w. The power supply portion 22 extends in the axial direction Dz from an edge of the notch 21 that faces the flat conductor 3A in the axial direction Dz across the slot 5A toward the flat conductor 3A.

[0028] Regarding the power supply portion 22, the flat conductor 3A has a hole 31. The power supply portion 22 passes through the hole 31 without contacting the flat conductor 3A and extends in the axial direction Dz to one surface of the printed circuit board 101 opposite to the installation surface of the flat conductor 3A. The power supply portion 22 is connected to the conductor pattern 101a of the printed circuit board 101 (see FIG. 5).

[0029] Strictly speaking, the slot 5A is formed along the circumferential direction of the tubular conductor 2A so as to be divided into two by the power supply portion 22. Note that the length of the slot 5A (notch 21) along the circumferential direction of the tubular conductor 2A described above means the entire length of the slot 5A (notch 21) including the power supply portion 22 along the circumferential direction of the tubular conductor 2A.

[0030] The power supply unit 22 is connected to the power supply line 102 via the conductor pattern 101a of the printed circuit board 101. In this embodiment, the power supply line 102 is formed, for example, by a coaxial cable. The coaxial cable that is the power supply line 102 has a center conductor and an outer conductor surrounding the center conductor. The power supply unit 22 is connected to the center conductor of the power supply line 102 via the conductor pattern 101a. The outer conductor of the power supply line 102 is connected to the power supply point 32 of the flat conductor 3A.

[0031] The power supply portion 22 supplies power to the slot 5A. This allows the antenna device 1 to function as a slot antenna. The position of the power supply portion 22 along the circumferential direction of the tubular conductor 2A with respect to the slot 5A (notch 21) may be determined appropriately so as to obtain the characteristics desired as a slot antenna.

[0032] The parasitic conductor 4A is located in an inner region of the tubular conductor 2A as viewed from the axial direction Dz. More specifically, the parasitic conductor 4A is disposed inside the tubular conductor 2A in the axial direction Dz and inside the tubular conductor 2A in the transverse direction Dx-Dy. The parasitic conductor 4A is disposed apart from the tubular conductor 2A and the flat conductors 3A and 3B. The parasitic conductor 4A is L-shaped as viewed from the transverse direction Dy and extends along the transverse direction Dy. The parasitic conductor 4A has a flat portion 41A and a partition portion 42A.

[0033] The flat plate portion 41A is disposed at the other end of the tubular conductor 2A in the axial direction Dz and extends in the transverse direction Dx-Dy. The flat plate portion 41A extends inward from the other end of the tubular conductor 2A in the axial direction Dz in the transverse direction Dx-Dy. The flat plate portion 41A is disposed at the same position as the flat conductor 3B in the axial direction Dz and extends in parallel to the flat conductor 3B in the transverse direction Dx-Dy. The flat plate portion 41A has a rectangular shape and is located toward one end of the transverse direction Dx inside the tubular conductor 2A. In other words, the flat plate portion 41A closes a portion of the opening at the other end of the tubular conductor 2A in the axial direction Dz.

[0034] The partition portion 42A is disposed inside the tubular conductor 2A and extends in the axial direction Dz and the transverse direction Dy. The partition portion 42A extends from one side of the flat portion 41A, which is an end portion of the flat portion 41A and extends in the transverse direction Dy, toward one end side in the axial direction Dz (toward the flat conductor 3A). The partition portion 42A extends between two peripheral walls 2w of the tubular conductor 2A that face each other in the transverse direction Dy. The partition portion 42A extends parallel to and faces the two peripheral walls 2w that face each other in the transverse direction Dx.

[0035] The parasitic conductor 4A is attached to the tubular conductor 2A, the flat conductor 3A, or both of them by an insulating support member (not shown). The parasitic conductor 4A may also be attached by soldering to a parasitic conductor pattern (not shown) provided on the printed circuit board 101 insulated from the flat conductor 3A. No current is fed to the parasitic conductor 4A.

[0036] According to the above configuration, the antenna device 1 includes a parasitic conductor 4A located in an inner region of the tubular conductor 2A as viewed in the axial direction Dz. This allows the parasitic conductor 4A to function as a wideband planar parasitic antenna. The inner region of the tubular conductor 2A as viewed in the axial direction Dz can be effectively utilized to install the parasitic conductor 4A in the antenna device 1. Therefore, the antenna device 1 can be made compact and can handle wideband radio waves.

[0037] The flat conductors 3A and 3B function as capacitors. This allows them to cancel out the inductance component that occurs when the size of the tubular conductor 2A in the cross direction Dx-Dy is reduced. That is, even when the size of the tubular conductor 2A in the cross direction Dx-Dy is reduced, the impedance matching between the antenna device 1 and the feeder line 102 can be improved, and the gain can be improved.

[0038] Furthermore, by joining the flat conductors 3A and 3B to the short tubular conductor 2A whose length in the axial direction Dz is less than λ / 4, it can be considered equivalent to substantially increasing the length in the axial direction Dz of the tubular conductor 2A. This ensures the function of the antenna device 1 as a slot antenna. In other words, by providing the flat conductors 3A and 3B, it is possible to improve the gain of the antenna device 1 while shortening the length in the axial direction Dz of the tubular conductor 2A.

[0039] The flat conductor 3A is formed as a conductor pattern on the printed circuit board 101. In this embodiment, the printed circuit board 101 has a rectangular shape extending in the intersecting direction Dx-Dy. The printed circuit board 101 is larger than the flat conductor 3A, which is a conductor pattern. In this embodiment, each of the four sides of the outer edge of the rectangle of the flat conductor 3A extends parallel to one of the four sides of the outer edge of the rectangle of the printed circuit board 101.

[0040] By forming the flat conductor 3A as a conductor pattern on the printed circuit board 101, the flat conductor 3A can be easily formed using, for example, a control board, etc. This allows for an increased mounting density on the printed circuit board 101, and makes it possible to reduce the size of the antenna device 1.

[0041] In this embodiment, the flat portion 41A of the parasitic conductor 4A closes approximately half of the opening of the tubular conductor 2A at the other end of the tubular conductor 2A in the axial direction Dz. That is, the parasitic conductor 4A covers at least a portion of the opening at the other end of the tubular conductor 2A in the axial direction Dz. The shape, size, and arrangement of the flat portion 41A can be changed as desired. This allows the band of electromagnetic waves transmitted or received by the antenna device 1 to be changed as desired.

[0042] The parasitic conductor 4A also has a partition portion 42A extending in the axial direction Dz. As with the flat plate portion 41A, the shape, size, and arrangement of the partition portion 42A can be changed as desired. This allows the band of electromagnetic waves transmitted or received by the antenna device 1 to be changed as desired.

[0043] 2. Second Embodiment Fig. 6 is a schematic perspective view of the antenna device 1 of the second embodiment. Fig. 7 is a perspective view of the antenna device 1 of Fig. 6 as seen from below. Fig. 8 is a plan view of the antenna device 1 of Fig. 6. Note that the basic configurations of the second to fifth embodiments are the same as those of the first embodiment described above, and therefore common components may be given the same reference numerals or names as before, and their description may be omitted.

[0044] The antenna device 1 of the second embodiment includes a tubular conductor 2A, flat conductors 3A and 3B, and a parasitic conductor 4B.

[0045] The parasitic conductor 4B is located in an inner region of the tubular conductor 2A as viewed from the axial direction Dz. More specifically, the parasitic conductor 4B is disposed inside the tubular conductor 2A in the axial direction Dz and inside the tubular conductor 2A in the transverse direction Dx-Dy. The parasitic conductor 4B is disposed apart from the tubular conductor 2A and the flat conductors 3A and 3B. The parasitic conductor 4B is L-shaped as viewed from the transverse direction Dy and extends along the transverse direction Dy. The parasitic conductor 4B has a flat portion 41B and a partition portion 42B.

[0046] The flat plate portion 41B is disposed at the other end of the tubular conductor 2A in the axial direction Dz and extends in the transverse direction Dx-Dy. The flat plate portion 41B extends inward from the other end of the tubular conductor 2A in the axial direction Dz in the transverse direction Dx-Dy. The flat plate portion 41B is disposed at the same position as the flat conductor 3B in the axial direction Dz and extends in parallel to the flat conductor 3B in the transverse direction Dx-Dy. The flat plate portion 41B has a rectangular shape and exists inside the tubular conductor 2A over substantially the entire area in the transverse direction Dx-Dy. In other words, the flat plate portion 41B closes substantially the entire area of ​​the opening at the other end of the tubular conductor 2A in the axial direction Dz.

[0047] The partition portion 42B is disposed inside the tubular conductor 2A and extends in the axial direction Dz and the transverse direction Dy. The partition portion 42B extends from one side of the flat portion 41B, which is an end portion thereof and extends in the transverse direction Dy, toward one end side in the axial direction Dz (toward the flat conductor 3A). The partition portion 42B extends between two peripheral walls 2w of the tubular conductor 2A that face each other in the transverse direction Dy. The partition portion 42B extends parallel to and faces the two peripheral walls 2w that face each other in the transverse direction Dx. The partition portion 42B is adjacent to one of the two peripheral walls 2w of the tubular conductor 2A that face each other in the transverse direction Dx.

[0048] The parasitic conductor 4B is attached to the tubular conductor 2A, the flat conductor 3A, or both of them by an insulating support member (not shown). The parasitic conductor 4B may also be attached by soldering to a parasitic conductor pattern (not shown) provided on the printed circuit board 101 insulated from the flat conductor 3A. No current is fed to the parasitic conductor 4B.

[0049] According to the above configuration, the parasitic conductor 4B can function as a wideband planar parasitic antenna. The parasitic conductor 4B can be installed in the antenna device 1 by effectively utilizing the inner area of ​​the tubular conductor 2A as viewed from the axial direction Dz. Therefore, the antenna device 1 can handle wideband radio waves with a compact configuration.

[0050] 3. Third Embodiment 9 is a schematic perspective view of the antenna device 1 of the third embodiment. The antenna device 1 of the third embodiment includes a tubular conductor 2A, flat conductors 3A and 3B, and a parasitic conductor 4C.

[0051] The parasitic conductor 4C is located in an inner region of the tubular conductor 2A as viewed from the axial direction Dz. More specifically, the parasitic conductor 4C is disposed inside the tubular conductor 2A in the axial direction Dz and inside the tubular conductor 2A in the transverse direction Dx-Dy. The parasitic conductor 4C is disposed at a distance from the tubular conductor 2A and the flat conductors 3A and 3B.

[0052] The parasitic conductor 4C is located at the other end of the tubular conductor 2A in the axial direction Dz and extends in the transverse direction Dx-Dy. The parasitic conductor 4C is located at the same position as the flat conductor 3B in the axial direction Dz and extends parallel to the flat conductor 3B in the transverse direction Dx-Dy.

[0053] The parasitic conductor 4C has an annular shape extending along the circumferential direction of the tubular conductor 2A. Specifically, the parasitic conductor 4C is C-shaped when viewed in the axial direction Dz. A portion of the parasitic conductor 4C is open near one of the two circumferential walls 2w of the tubular conductor 2A that face each other in the transverse direction Dy. The position and length of the open portion of the C-shaped parasitic conductor 4C can be changed as desired.

[0054] The parasitic conductor 4C is attached to the tubular conductor 2A, the flat conductor 3A, or both of them by an insulating support member (not shown). The parasitic conductor 4C may have a support (not shown) branched from the middle of its C-shape or one or both of its open ends bent and extending along the axial direction Dz to the printed circuit board 101, and the support may be attached by soldering to a parasitic conductor pattern (not shown) provided on the printed circuit board 101 insulated from the flat conductor 3A.

[0055] According to the above configuration, the parasitic conductor 4C can function as a wideband planar parasitic antenna. The parasitic conductor 4C can be installed in the antenna device 1 by effectively utilizing the inner area of ​​the tubular conductor 2A as viewed from the axial direction Dz. Therefore, the antenna device 1 can handle wideband radio waves with a compact configuration.

[0056] 4. Fourth Embodiment 10 is a schematic perspective view of the antenna device 1 of the fourth embodiment. The antenna device 1 of the fourth embodiment includes a tubular conductor 2A, flat conductors 3A and 3B, and a parasitic conductor 4D.

[0057] The parasitic conductor 4D is located in an inner region of the tubular conductor 2A as viewed from the axial direction Dz. More specifically, the parasitic conductor 4D is disposed inside the tubular conductor 2A in the axial direction Dz and inside the tubular conductor 2A in the transverse direction Dx-Dy. The parasitic conductor 4D is disposed apart from the tubular conductor 2A and the flat conductors 3A and 3B.

[0058] The parasitic conductor 4D is located at the other end of the tubular conductor 2A in the axial direction Dz and extends in the transverse direction Dx-Dy. The parasitic conductor 4D is located at the same position as the flat conductor 3B in the axial direction Dz and extends parallel to the flat conductor 3B in the transverse direction Dx-Dy.

[0059] The parasitic conductor 4D is arranged in a ring shape along the circumferential direction of the tubular conductor 2A. Specifically, the parasitic conductor 4D is C-shaped when viewed in the axial direction Dz. A portion of the parasitic conductor 4D is open near one of the two peripheral walls 2w of the tubular conductor 2A that face each other in the cross direction Dy.

[0060] Furthermore, the parasitic conductor 4D has a peripheral wall 4w extending in the axial direction Dz. More specifically, the parasitic conductor 4D has five peripheral walls 4w that face the four peripheral walls 2w of the tubular conductor 2A in the transverse direction Dx-Dy. The position and length of the open portion of the C-shaped parasitic conductor 4D can be changed as desired.

[0061] The parasitic conductor 4D is attached to the tubular conductor 2A, the flat conductor 3A, or both of them by an insulating support member (not shown). The parasitic conductor 4D may also be attached by soldering to a parasitic conductor pattern (not shown) provided on the printed circuit board 101 insulated from the flat conductor 3A.

[0062] According to the above configuration, the parasitic conductor 4D can function as a wideband planar parasitic antenna. The parasitic conductor 4D can be installed in the antenna device 1 by effectively utilizing the inner area of ​​the tubular conductor 2A as viewed from the axial direction Dz. Therefore, the antenna device 1 can handle wideband radio waves with a compact configuration.

[0063] 5. Fifth Embodiment Fig. 11 is a schematic perspective view of the antenna device 1 of the fifth embodiment. Fig. 12 is a side view of the antenna device of Fig. 11. The antenna device 1 of the fifth embodiment includes a tubular conductor 2A, flat conductors 3A and 3B, and a parasitic conductor 4E.

[0064] The parasitic conductor 4E has a flat plate shape extending in the transverse direction Dx-Dy and is arranged at a distance from the tubular conductor 2A on the other end side of the axial direction Dz of the tubular conductor 2A. The parasitic conductor 4E is also a rectangular shape of the same size as the flat conductor 3B and overlaps exactly when viewed from the axial direction Dz. The parasitic conductor 4E is arranged parallel to and at a distance from the flat conductor 3B. A portion of the parasitic conductor 4E is located in the inner region of the tubular conductor 2A when viewed from the axial direction Dz.

[0065] The parasitic conductor 4E is attached to the tubular conductor 2A, the flat conductor 3B, or both of them by an insulating support member (not shown). The parasitic conductor 4E may also include a support (not shown) extending along the axial direction Dz to the printed circuit board 101 in the inner region of the tubular conductor 2A as seen from the axial direction Dz, and the support may be attached by soldering to a parasitic conductor pattern (not shown) provided on the printed circuit board 101 insulated from the flat conductor 3A. The parasitic conductor 4E is not fed with electricity.

[0066] According to the above configuration, the parasitic conductor 4E can function as a wideband planar parasitic antenna. The parasitic conductor 4E can be installed in the antenna device 1 by effectively utilizing the inner area of ​​the tubular conductor 2A as viewed from the axial direction Dz. Therefore, the antenna device 1 can handle wideband radio waves with a compact configuration.

[0067] 6. Sixth Embodiment Fig. 13 is a schematic perspective view of the antenna device 1 of the sixth embodiment. Fig. 14 is a side view of the antenna device of Fig. 13. The antenna device 1 of the sixth embodiment includes a tubular conductor 2B and flat conductors 3C and 3D.

[0068] The tubular conductor 2B extends in the axial direction Dz. In this embodiment, the tubular conductor 2B has a rectangular tube shape and a square cross section in the transverse direction Dx-Dy. That is, the tubular conductor 2B is composed of four flat peripheral walls 2w extending in the axial direction Dz and arranged in a square cross section. Note that the tubular conductor 2B may have a cross section in another polygonal shape, such as a triangle or a pentagon, or may be cylindrical. Both ends of the tubular conductor 2B in the axial direction Dz are open.

[0069] The flat conductor 3C is disposed at one end of the tubular conductor 2B in the axial direction Dz. The flat conductor 3D is disposed at the other end of the tubular conductor 2B in the axial direction Dz. The flat conductors 3C and 3D are formed integrally with the tubular conductor 2B, for example. In other words, the flat conductors 3C and 3D are the same member as the tubular conductor 2B and are formed from a sheet metal of a conductive material such as copper or iron.

[0070] The flat conductor 3C has a rectangular shape extending outside and inside the tubular conductor 2B in the transverse direction Dx-Dy. The flat conductor 3C is arranged so as to close one end of the tubular conductor 2B in the axial direction Dz. The flat conductor 3D has a rectangular ring shape extending outside the tubular conductor 2B in the transverse direction Dx-Dy. Each of the four sides of the outer edge of the rectangular shape of the flat conductors 3C and 3D extends parallel to one of the four peripheral walls 2w that constitute the tubular conductor 2B. The flat conductors 3C and 3D are separated in the axial direction Dz across the tubular conductor 2B and extend parallel to the transverse direction Dx-Dy. The outer shapes and sizes of the flat conductors 3C and 3D may be different from each other or may be the same.

[0071] The tubular conductor 2B includes slots 5B and 5C. The slots 5B and 5C are rectangular when viewed from the transverse direction Dx-Dy and penetrate the peripheral wall 2w of the tubular conductor 2B in the transverse direction Dx-Dy. The slots 5B and 5C are formed in a portion of the tubular conductor 2B along the circumferential direction.

[0072] The slot 5B is located approximately in the center of the tubular conductor 2B in the axial direction Dz. The slot 5B extends continuously across the three peripheral walls 2w of the tubular conductor 2B. The slot 5C is located at the other end of the tubular conductor 2B in the axial direction Dz and adjacent to the flat conductor 3D. The slot 5C extends across the entire area of ​​the peripheral wall 2w where the slot 5B is not formed in the cross direction Dy.

[0073] Antenna device 1 has a power feed unit (not shown) for slot 5B. This power feed unit feeds power to slot 5B. Antenna device 1 does not have a power feed unit for slot 5C. In other words, slot 5C is a non-power-fed slot.

[0074] According to the above configuration, by providing the slot 5C, which is a parasitic slot, it is possible to set a resonant frequency near the required band, thereby making it possible to broaden the antenna characteristics of the required band in the antenna device 1.

[0075] 7. Seventh Embodiment Fig. 15 is a schematic perspective view of the antenna device 1 of the seventh embodiment. Fig. 16 is a side view of the antenna device of Fig. 15. Note that the basic configurations of the seventh and eighth embodiments are the same as those of the sixth embodiment described above, and therefore common components may be given the same reference numerals or names as before, and descriptions thereof may be omitted.

[0076] The antenna device 1 of the seventh embodiment includes a tubular conductor 2B and flat conductors 3C and 3D.

[0077] The tubular conductor 2B includes slots 5B and 5D. The slots 5B and 5D are rectangular when viewed from the transverse direction Dx-Dy and penetrate the peripheral wall 2w of the tubular conductor 2B in the transverse direction Dx-Dy. The slots 5B and 5D are formed in a portion of the tubular conductor 2B along the circumferential direction.

[0078] The slot 5B is located approximately in the center of the tubular conductor 2B in the axial direction Dz. The slot 5B extends continuously across the three peripheral walls 2w of the tubular conductor 2B. The slot 5D is located approximately in the center of the tubular conductor 2B in the axial direction Dz, at the same position as the slot 5B with respect to the axial direction Dz. The slot 5D extends continuously across the three peripheral walls 2w, including the peripheral wall 2w where the slot 5B is not formed. Both ends of the slots 5B and 5D are spaced apart in the transverse direction Dx-Dy and face each other in the transverse direction Dx.

[0079] Antenna device 1 has a feeder (not shown) for slot 5B. This feeder feeds power to slot 5B. Antenna device 1 does not have a feeder for slot 5D. In other words, slot 5D is a non-power-fed slot.

[0080] According to the above configuration, by providing the slot 5D, which is a parasitic slot, it is possible to set a resonant frequency near the required band, thereby making it possible to broaden the antenna characteristics of the required band in the antenna device 1.

[0081] 8. Eighth Embodiment Fig. 17 is a schematic perspective view of the antenna device 1 of the eighth embodiment. Fig. 18 is a side view of the antenna device of Fig. 17. The antenna device 1 of the eighth embodiment includes a tubular conductor 2B and flat conductors 3C and 3D.

[0082] The tubular conductor 2B includes a slot 5E. The slot 5E has a rectangular shape when viewed in the transverse direction Dx-Dy, and penetrates the peripheral wall 2w of the tubular conductor 2B in the transverse direction Dx-Dy. The slot 5E extends continuously over the four peripheral walls 2w of the tubular conductor 2B. The slot 5E is formed in a spiral shape that makes approximately two turns in the circumferential direction of the tubular conductor 2B.

[0083] The antenna device 1 includes a power feeder (not shown) for the slot 5E. The power feeder feeds power to the slot 5E.

[0084] According to the above configuration, when the required slot length is long compared to the size of the cylindrical conductor 2B, the slot can be provided in a spiral shape, which makes it possible to reduce the size of the antenna device 1.

[0085] <9. Things to keep in mind> Various technical features disclosed as embodiments in this specification may be modified in various ways without departing from the spirit of the technical creation. In other words, the above-described embodiments are illustrative in all respects and are not limiting. The technical scope of the present invention is defined by the claims, not by the description of the above-described embodiments, and includes all modifications that fall within the meaning and scope of the claims. Furthermore, the multiple embodiments described in this specification may be combined as appropriate to the extent possible. [Explanation of symbols]

[0086] 1 Antenna device 2A, 2B cylindrical conductor 3A, 3B, 3C, 3D flat conductor 4A, 4B, 4C, 4D, 4E Non-powered conductors 4w surrounding wall Slots 5A, 5B, 5C, 5D, and 5E 21 Notch 22 Power supply unit 31 Hole 41A, 41B Flat plate part 42A, 42B Partition Dx, Dy cross direction Dz axis direction

Claims

1. A cylindrical conductor; a flat conductor disposed at least at one end of the cylindrical conductor in the axial direction and extending in a direction intersecting the axial direction; Equipped with The cylindrical conductor is a slot formed in a portion of the cylindrical conductor along a circumferential direction and extending in the intersecting direction; a power supply unit that supplies power to the slot; and a parasitic conductor located in an inner region of the cylindrical conductor as viewed in the axial direction, The parasitic conductor has a partition portion extending in the axial direction. Antenna device.

2. A cylindrical conductor; a flat conductor disposed at least at one end of the cylindrical conductor in the axial direction and extending in a direction intersecting the axial direction; Equipped with The cylindrical conductor is a slot formed in a portion of the cylindrical conductor along a circumferential direction and extending in the intersecting direction; a power supply unit that supplies power to the slot; and a parasitic conductor located in an inner region of the cylindrical conductor as viewed in the axial direction, the parasitic conductor has an annular shape extending along a circumferential direction of the cylindrical conductor, and has a peripheral wall disposed annularly along the circumferential direction of the cylindrical conductor and extending in the axial direction; Antenna device.

3. 3. The antenna device according to claim 1, wherein the parasitic conductor covers at least a part of an opening at an end of the cylindrical conductor in the axial direction.

4. 3. The antenna device according to claim 1, wherein the parasitic conductor has a flat plate shape extending in the intersecting direction and is disposed at the end of the cylindrical conductor in the axial direction and spaced apart from the cylindrical conductor.

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