Antenna device

Abstract

To provide an antenna device capable of more reducing an occupation region of a construction element in a construction of which a size is miniaturized.SOLUTION: An antenna device comprises: a flat-plate conductor; and a bent-shaped conductor that includes a plurality of side wall parts arranged so as to be stood on the flat-plate conductor, and in which each side wall part is bent in view of an opposite direction with the flat-plate conductor by the plurality of bent parts. A slot formed by a gap is provided to between the flat-plate conductor and the bent-shaped conductor, and a region surrounded by each side wall part is formed in an L-character shape in viewed from the opposite direction.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Conventionally, an antenna device may be mounted on a moving body such as an automobile, a bus, or a railway vehicle. For example, a non-directional antenna for a moving body is known, which includes a cylindrical body made of a conductive material having notches (slots) formed in the circumferential direction, and end plates made of a conductive material having a diameter larger than that of the cylindrical body and fixed to both ends of the cylindrical body (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described conventional antenna for a moving body, the inside of the cylindrical body is an unused space and not utilized, and the problem is that the occupied area of the cylindrical body is large.

[0005] In view of the above problems, an object of the present invention is to provide an antenna device having a configuration in which miniaturization is achieved and the occupied area of the components can be made smaller.

Means for Solving the Problems

[0006] An exemplary antenna device of the present invention includes a flat conductor, and a bent conductor having a plurality of side wall portions erected on the flat conductor and bent by a plurality of bent portions as viewed from the direction facing the flat conductor, and a slot formed of a gap is provided between the flat conductor and the bent conductor, and the region surrounded by the side wall portions is formed in an L shape as viewed from the facing direction.

Advantages of the Invention

[0007] According to the configuration of the present invention, in the antenna device, a miniaturized configuration is achieved, and the occupied area of the components can be made smaller.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0009] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In this description, the directions parallel to the flat conductor 2 to be described later are indicated by the arrow Dx and the arrow Dy representing the orthogonal coordinate system. That is, the flat conductor 2 extends along the Dx-Dy plane. Hereinafter, the direction parallel to the flat conductor 2 may be referred to as the Dx-Dy plane direction. Further, the opposing direction, which is the direction opposite to the direction parallel to the flat conductor 2 (Dx-Dy plane direction), is indicated by the arrow Dz. The opposing direction Dz is perpendicular to the Dx-Dy plane in this description, but is not strictly limited to being perpendicular, and includes substantially perpendicular.

[0010] FIG. 1 is a schematic perspective view of the antenna device 1 according to the embodiment. FIG. 2 is a schematic perspective view of the antenna device 1 in FIG. 1 as viewed from the back side. FIGS. 3, 4, and 5 are a front view, a side view, and a top view of the antenna device 1 in FIG. 1. In FIGS. 1, 2, 3, and 4, the drawing of the power supply line 102 described later is omitted.

[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 the moving body other than a vehicle may include a ship, an aircraft, a robot, and the like. Further, the antenna device 1 may be mounted on something other than a moving body. In the present embodiment, the antenna device 1 is an in-vehicle antenna device.

[0012] As shown in FIGS. 1 and 2, the antenna device 1 includes a flat conductor 2 and a bent conductor 3.

[0013] The flat conductor 2 is a flat member extending along the Dx-Dy plane shown in FIGS. 1 and 2. The flat conductor 2 is disposed at one end of the bent conductor 3 with respect to the opposing direction Dz. The flat conductor 2 is made of a conductive material such as copper or iron, and is formed of sheet metal in the present embodiment. The flat conductor 2 is made of, for example, the same conductive material as the bent conductor 3.

[0014] In the present embodiment, the flat conductor 2 has a rectangular shape extending outside and inside the bent conductor 3 with respect to the Dx-Dy plane direction. Note that the flat conductor 2 may have other polygonal shapes such as a triangle or a pentagon, or may have a circular shape. The outer edge of the flat conductor 2 is located outside the outer edge of the bent conductor 3 with respect to the Dx-Dy plane direction. Further, the flat conductor 2 extends over the entire inner region of the bent conductor 3 with respect to the Dx-Dy plane direction.

[0015] The bent conductor 3 is arranged in the height direction in the facing direction Dz facing the flat conductor 2, and extends in a direction parallel to the flat conductor 2 (in the Dx-Dy plane direction) via a bent portion 3b described later. The bent conductor 3 is composed of a sheet metal of a conductive material such as copper or iron. In the present embodiment, the bent conductor 3 has a plurality of side wall portions 3w, a plurality of bent portions 3b, and a plurality of end plate portions 3e.

[0016] The plurality of side wall portions 3w are erected on the flat conductor 2. That is, the plurality of side wall portions 3w extend in a direction away from the flat conductor 2 along the facing direction Dz. Further, the plurality of side wall portions 3w are bent as viewed from the facing direction Dz by the plurality of bent portions 3b. The bent conductor 3 is connected to the flat conductor 2 on one end side in the facing direction Dz.

[0017] The plurality of bent portions 3b have bending lines extending in the facing direction Dz and are bent in the same direction. Between adjacent bent portions 3b, a first side wall portion 3w1 to a sixth side wall portion 3w6 are formed.

[0018] Note that the side wall portion 3w includes a first side wall portion 3w1, a second side wall portion 3w2, a third side wall portion 3w3, a fourth side wall portion 3w4, a fifth side wall portion 3w5, and a sixth side wall portion 3w6. In this document, when there is no need for particular limitation, it may be simply described as the "side wall portion 3w".

[0019] In the present embodiment, the antenna device 1 corresponds to one type of electromagnetic wave (radio wave). The antenna device 1 constitutes a transmitting antenna or a receiving antenna. When the wavelength of the electromagnetic wave transmitted or received by the antenna device 1 is λ, preferably, the length of the bent conductor 3 in the facing 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 conductor 2, which will be described later. When there is a margin at the location where the antenna device 1 is installed in the facing direction Dz, the length of the bent conductor 3 in the facing direction Dz may be λ / 4 or more.

[0020] A slot 31 formed of a gap is provided between the flat conductor 2 and the bent conductor 3. Further, the bent conductor 3 includes a power feeding portion 32.

[0021] The slot 31 is disposed at one end of the bent conductor 3 facing the flat conductor 2 in the facing direction Dz. The slot 31 is formed in a part of the side wall portion 3w of the bent conductor 3. The slot 31 is constituted by a notch recessed in a direction away from the flat conductor 2 in the facing region of the bent conductor 3 with the flat conductor 2 with respect to the facing direction Dz. In other words, the bent conductor 3 is joined to the flat conductor 2 by the remaining part of the side wall portion 3w where the slot 31 is not formed at one end in the facing direction Dz facing the flat conductor 2. Note that the bent conductor 3 and the flat conductor 2 may be directly joined or joined by being inserted into a connector or a slit.

[0022] The slot 31 penetrates the side wall portion 3w in the direction Dx or the direction Dy. The slot 31 is composed of a gap extending along the direction (Dx - Dy plane direction) parallel to the flat conductor 2. In the present embodiment, the slot 31 of the bent conductor 3 is a slot of a so-called slot antenna that extends in a strip shape when viewed from the direction Dx or the direction Dy. The total length of the slot 31 along the bent conductor 3 (the lengths along the directions Dx and Dy) is λ / 2 with respect to the wavelength λ of the electromagnetic wave. The length of the slot 31 in the facing direction Dz is a length sufficiently small with respect to the wavelength λ. The length of the slot 31 in the facing direction Dz is, for example, λ / 100 or the like.

[0023] The length of the entire bent conductor 3 (the length in the direction (Dx - Dy plane direction) parallel to the flat conductor 2 in a state where the bent conductor 3 is extended flat) is preferably in the range from λ / 2 to 2λ / 3 with respect to the length λ / 2 of the slot 31. Also, the length of one side of the flat conductor 2 having a rectangular shape when viewed from the facing direction Dz is preferably [the length of one side in the direction Dx or the direction Dy of the entire bent conductor 3 viewed from the facing direction Dz] × 7 / 5 or more.

[0024] More specifically, the slot 31 has a plurality of portions with different lengths in the opposing direction Dz (the length in the direction orthogonal to the longitudinal direction of the gap, the width with respect to the longitudinal direction of the gap), and further, both end portions in the direction Dx or the direction Dy are bent in a crank shape in the opposing direction Dz and the direction Dx or the direction Dy. Details of the shape of such a slot 31 will be described later.

[0025] The power feeding unit 32 is disposed on one side wall portion 3w (the fifth side wall portion 3w5) among the plurality of side wall portions 3w. Further, in the power feeding unit 32, the flat plate conductor 2 has a protruding portion 2a extending toward the side wall portion 3w (the fifth side wall portion 3w5) of the bent conductor 3.

[0026] The power feeding unit 32 is connected to the power feeding line 102. In the present embodiment, the power feeding line 102 is composed of, for example, a coaxial cable. The coaxial cable that is the power feeding line 102 has a center conductor and an outer conductor surrounding the center conductor. In the power feeding unit 32, the side wall portion 3w (the fifth side wall portion 3w5) of the bent conductor 3 is connected to the center conductor of the power feeding line 102. The outer conductor of the power feeding line 102 is connected to the protruding portion 2a of the flat plate conductor 2.

[0027] The power feeding unit 32 feeds power to the slot 31. Thereby, the antenna device 1 functions as a slot antenna. Note that the position of the power feeding unit 32 along the bent conductor 3 with respect to the slot 31 may be appropriately determined so that the characteristics required for the slot antenna are obtained.

[0028] In this embodiment, the power supply unit 32 is disposed above the main body portion of the flat conductor 2 extending in a flat plate shape (above the upper side in the facing direction Dz in FIGS. 3 and 4), and is spaced apart from the main body portion of the flat conductor 2. Thereby, the flat conductor 2 has a protruding portion 2a in the power supply unit 32. The arrangement of the power supply unit 32 is an arrangement based on the wiring position of the power supply line 102, and the power supply unit 32 may be arranged on the main body portion of the flat conductor 2 by eliminating the protruding portion 2a. In that case, specifically, the center conductor of the power supply line 102 is connected to the side wall portion 3w (the fifth side wall portion 3w5) of the bent conductor 3, and the outer conductor of the power supply line 102 is connected to the flat conductor 2. The position where the outer conductor of the power supply line 102 is connected to the flat conductor 2 may be a position corresponding to the side wall portion 3w (the fifth side wall portion 3w5) of the bent conductor 3 as viewed from the facing direction Dz, or may be another position of the flat conductor 2.

[0029] Also, as shown in FIGS. 1 and 5, the bent conductor 3 has a first rectangular region R1 and a second rectangular region R2, which are two rectangular regions, in the direction facing the flat conductor 2, that is, as viewed from the facing direction Dz. The longitudinal direction of the first rectangular region R1 extends along the direction Dx. The longitudinal direction of the second rectangular region R2 extends along the direction Dy. The region surrounded by the side wall portions of the bent conductor 3 is formed in a substantially L shape as viewed from the direction facing the flat conductor 2, that is, from the facing direction Dz.

[0030] Here, the "rectangular shape" does not necessarily have to be a geometrically exact rectangle, and it may be generally rectangular. For example, the "rectangular shape" may be a parallelogram or a rhombus in which all angles are not 90 degrees but are between 80 degrees and 100 degrees. Also, the "L shape" here does not necessarily have to be such that two rectangles intersect at a right angle (90 degrees). For example, the "L shape" may be generally L-shaped such that two rectangles intersect at an angle between 80 degrees and 100 degrees.

[0031] According to the above configuration, the inner space of the bent conductor 3 as viewed from the facing direction Dz can be reduced. Therefore, the antenna device 1 has a configuration in which miniaturization is achieved, and it becomes possible to further reduce the occupied area of the bent conductor 3. As a result, in the antenna device 1, a free space Rv shown in FIG. 5 is generated, and the free space Rv can be effectively utilized for mounting a matching circuit, an amplifier circuit, or other antenna elements of the antenna device 1.

[0032] Note that the flat conductor 2 serves as a capacitor. For this purpose, the inductance component generated by reducing the size of the bent conductor 3 on the Dx-Dy plane can be canceled out. That is, even when the size of the bent conductor 3 on the Dx-Dy plane is reduced, good impedance matching between the antenna device 1 and the feeding line 102 can be achieved, and the gain can be improved.

[0033] Also, it can be considered that the flat conductor 2 is joined to the short bent conductor 3 having a length in the facing direction Dz of less than λ / 4, which is equivalent to the case where the length of the bent conductor 3 in the facing direction Dz is substantially increased. Thereby, it is possible to ensure the function of the antenna device 1 as a slot antenna. That is, by providing the flat conductor 2, it is possible to improve the gain of the antenna device 1 while shortening the length of the bent conductor 3 in the facing direction Dz.

[0034] Also, the flat conductor 2 is formed of sheet metal in this embodiment. Thereby, the housing (case) of the antenna device 1 can be configured to also serve as the flat conductor 2. Therefore, it is possible to reduce the number of parts and miniaturize the antenna device 1. Further, in this case, a printed circuit board, which is a control board or the like of the antenna device 1, can be disposed so as to float above the flat conductor 2, and for example, the height can be increased when mounting another antenna element on the printed circuit board.

[0035] Further, the flat conductor 2 may be constituted by a conductor pattern formed on a printed circuit board. For example, the printed circuit board is rectangular and extends in the Dx-Dy plane direction, and is larger than the flat conductor 2 formed as the conductor pattern.

[0036] When the flat conductor 2 is used as the conductor pattern of the printed circuit board, for example, by using a control board or the like, the flat conductor 2 can be easily formed. Therefore, there is no need to separately prepare another member as the flat conductor 2, and it becomes possible to improve productivity. In addition, the mounting density on the printed circuit board can be increased, and the antenna device 1 can be miniaturized.

[0037] Further, the bent conductor 3 has four end plate portions 3e. The end plate portion 3e includes a first end plate portion 3e1, a second end plate portion 3e2, a third end plate portion 3e3, and a fourth end plate portion 3e4. In this document, when there is no particular need for limitation, it may be simply described as the "end plate portion 3e".

[0038] The four end plate portions 3e are arranged on the opposite side of the flat conductor 2 with respect to the opposing direction Dz in the bent conductor 3. Further, the end plate portion 3e is connected to one end portion of the side wall portion 3w in the opposing direction Dz. The end plate portion 3e is integrally formed with the same member as the side wall portion 3w and is composed of a sheet metal of a conductive material such as copper or iron.

[0039] The end plate portion 3e extends along the Dx-Dy plane. In other words, the end plate portion 3e faces the flat conductor 2 and extends in a direction parallel to the flat conductor 2. The end plate portion 3e extends outward in the direction Dx or the direction Dy with respect to the inside of the bent conductor 3 surrounded by the plurality of side wall portions 3w. The end plate portion 3e is rectangular when viewed from the opposing direction Dz.

[0040] By disposing the end plate portion 3e at one end in the facing direction Dz of the bent conductor 3, it can be said that it is equivalent to the case where the length in the facing direction Dz of the bent conductor 3 is substantially increased as in the case of disposing the flat conductor 2. That is, by providing the end plate portion 3e, it becomes possible to improve the gain of the antenna device 1 while shortening the length in the facing direction Dz of the bent conductor 3 and reducing the size of the antenna device 1.

[0041] Subsequently, the detailed configuration of the bent conductor 3 will be described with reference to FIG. 6 in addition to FIGS. 1 to 5. FIG. 6 is a developed view of the bent conductor 3 of the antenna device 1 in FIG. 1.

[0042] As described above, the bent conductor 3 is formed of a sheet metal of a conductive material such as copper or iron. The bent conductor 3 is a single flat plate member in the developed flat state (see FIG. 6). That is, the bent conductor 3 shown in FIGS. 1 and 2 is formed by bending a single flat plate member.

[0043] As shown in FIG. 6, the bent conductor 3 developed on a single flat plate member has five bending lines BL1, four bending lines BL2, one cutting line CL1, a slot 31, and a feeding portion 32. Note that the bending line BL1 is the bending line of the bent portion 3b.

[0044] The six side wall portions 3w are connected via five bending lines BL1. The side wall portions 3w are arranged in the order of the first side wall portion 3w1, the second side wall portion 3w2, the third side wall portion 3w3, the fourth side wall portion 3w4, the fifth side wall portion 3w5, and the sixth side wall portion 3w6 along the direction parallel to the flat conductor 2 (the Dx-Dy plane direction) from one end side thereof. The bending line BL1 extends in the facing direction Dz. The bent portion 3b of the bent conductor 3 is formed by bending in the direction Dx or the direction Dy so that adjacent side wall portions 3w form a right angle at each of the five bending lines BL1.

[0045] The first side wall portion 3w1, the third side wall portion 3w3, and the fifth side wall portion 3w5 extend in the direction Dy (the first direction). The first side wall portion 3w1, the third side wall portion 3w3, and the fifth side wall portion 3w5 are arranged side by side in the direction Dx (the second direction) orthogonal to the direction Dy. Also, the second side wall portion 3w2, the fourth side wall portion 3w4, and the sixth side wall portion 3w6 extend in the direction Dx. The second side wall portion 3w2, the fourth side wall portion 3w4, and the sixth side wall portion 3w6 are arranged side by side in the direction Dy orthogonal to the direction Dx.

[0046] That is, the side wall portion 3w extends in the direction Dy (the first direction) parallel to the flat conductor 2 and is arranged side by side in the direction Dx (the second direction) orthogonal to the direction Dy at at least three locations, for example, the first side wall portion 3w1, the third side wall portion 3w3, and the fifth side wall portion 3w5. Also, the side wall portion 3w extends in the direction Dx parallel to the flat conductor 2 and is arranged side by side in the direction Dy orthogonal to the direction Dx at at least three locations, for example, the second side wall portion 3w2, the fourth side wall portion 3w4, and the sixth side wall portion 3w6.

[0047] Regarding the first side wall portion 3w1, the third side wall portion 3w3, and the fifth side wall portion 3w5, among the third side wall portion 3w3 and the fifth side wall portion 3w5 arranged at both ends in the direction Dx (the second direction), the fifth side wall portion 3w5 has a shorter length in the direction Dy (the first direction) than the third side wall portion 3w3. Also, regarding the second side wall portion 3w2, the fourth side wall portion 3w4, and the sixth side wall portion 3w6, among the second side wall portion 3w2 and the fourth side wall portion 3w4 arranged at both ends in the direction Dy, the second side wall portion 3w2 has a shorter length in the direction Dx than the fourth side wall portion 3w4.

[0048] Since one of the two side wall portions 3w arranged at both ends in the direction Dx or the direction Dy has a shorter length in the first direction than the other, it becomes easier to form the region surrounded by the side wall portions 3w into a substantially L-shaped when viewed from the opposing direction Dz. Thereby, in the antenna device 1, it becomes easier to form the empty region Rv shown in FIG. 5.

[0049] Further, the first side wall portion 3w1 extends in a direction Dy (first direction) parallel to the flat conductor 2. The second side wall portion 3w2 is connected to the first side wall portion 3w1 and extends in a direction Dx (second direction) orthogonal to the direction Dy. The third side wall portion 3w3 is connected to the second side wall portion 3w2 and extends in the direction Dy so as to face the first side wall portion 3w1. The fourth side wall portion 3w4 is connected to the third side wall portion 3w3 and extends in the direction Dx so as to face the second side wall portion 3w2. The fifth side wall portion 3w5 is connected to the fourth side wall portion 3w4 and extends in the direction Dy so as to face the third side wall portion 3w3. The sixth side wall portion 3w6 is connected to the fifth side wall portion 3w5 and extends in the direction Dx so as to face the fourth side wall portion 3w4.

[0050] According to the configuration from the first side wall portion 3w1 to the sixth side wall portion 3w6 described above, the region surrounded by the side wall portions 3w can be formed in a substantially L shape when viewed from the opposing direction Dz. Therefore, in the antenna device 1, it is possible to form the vacant region Rv shown in FIG. 5.

[0051] Each of the four end plate portions 3e is individually connected to the four side wall portions 3w via four bending lines BL2. The first end plate portion 3e1 is connected to the first side wall portion 3w1, the second end plate portion 3e2 is connected to the third side wall portion 3w3, the third end plate portion 3e3 is connected to the fourth side wall portion 3w4, and the fourth end plate portion 3e4 is connected to the sixth side wall portion 3w6. Also, the adjacent second end plate portion 3e2 and third end plate portion 3e3 are separated by a cut line CL1.

[0052] The four end plate portions 3e are formed by being bent at the four bending lines BL2 so as to be perpendicular to the connected side wall portions 3w. As described above, the end plate portion 3e extends parallel to and facing the flat conductor 2 along the Dx-Dy plane. As shown in FIG. 5, when viewed from the opposing direction Dz, the second end plate portion 3e2 and the third end plate portion 3e3 protrude outward from the bending line BL2 toward the outer edge portion of the flat conductor 2. Also, the first end plate portion 3e1 is located near the central portion of the flat conductor 2 and near the vacant region Rv when viewed from the opposing direction Dz.

[0053] Here, as shown in FIG. 6, with respect to the four end plate portions 3e, the length of the first end plate portion 3e1 in the facing direction Dz is longer than that of the other three end plate portions 3e. That is, after bending, the first end plate portion 3e1 has a longer protruding length from the bending line BL2 than the other three end plate portions 3e.

[0054] The performance of the antenna device 1 improves as the protruding length of the end plate portion 3e from the bending line BL2 increases. However, if the protruding length of the end plate portion 3e from the bending line BL2 becomes long, the antenna device 1 becomes large in the Dx-Dy plane direction, which is not preferable. That is, when viewed from the facing direction Dz, it is preferable that the second end plate portion 3e2 and the third end plate portion 3e3 disposed near the outer edge portion of the flat plate conductor 2 have the shortest protruding length from the bending line BL2 possible.

[0055] On the other hand, since the first end plate portion 3e1 is disposed near the center portion of the flat plate conductor 2 when viewed from the facing direction Dz, the protruding length from the bending line BL2 can be made longer than that of the second end plate portion 3e2 and the third end plate portion 3e3. Thereby, the performance of the antenna device 1 can be improved.

[0056] The slot 31 is disposed at one end portion of the bent conductor 3 in the facing direction Dz, on the side opposite to the end plate portion 3e with respect to the facing direction Dz. The slot 31 is formed in a part of the edge portion along the Dx-Dy plane direction in which the six side wall portions 3w are continuous. The slot 31 is configured by a notch recessed on the other end side of the bent conductor 3 where the end plate portion 3e is disposed with respect to the facing direction Dz.

[0057] The slot 31 has a plurality of portions with different lengths of the gap in the facing direction Dz. Specifically, the slot 31 has a first portion 311, a second portion 312, a third portion 313, a fourth portion 314, and a fifth portion 315 shown in FIG. 6. These plurality of portions are juxtaposed and continuous along the Dx-Dy plane direction, which is a direction parallel to the flat plate conductor 2.

[0058] The first part 311 extends along the Dx-Dy plane direction across the first side wall portion 3w1, the second side wall portion 3w2, and the third side wall portion 3w3. Specifically, the first part 311 extends along the Dx-Dy plane direction from near the central portion of the first side wall portion 3w1, through approximately half of the first side wall portion 3w1, the entire area of the second side wall portion 3w2, and the entire area of the third side wall portion 3w3, to the end of the third side wall portion 3w3.

[0059] The second part 312 is adjacent to the first part 311 in the Dx-Dy plane direction. The second part 312 extends along the Dx-Dy plane direction across the fourth side wall portion 3w4 and the fifth side wall portion 3w5. Specifically, the second part 312 extends along the Dx-Dy plane direction from the end of the fourth side wall portion 3w4 connected to the first part 311, through the entire area of the fourth side wall portion 3w4 and the entire area of the fifth side wall portion 3w5, to the end of the fifth side wall portion 3w5. The length Ds2 of the second part 312 in the opposite direction Dz of the gap is shorter than that of the first part 311 (Ds1).

[0060] Note that a power supply portion 32 is disposed on the fifth side wall portion 3w5. Since the protruding portion 2a of the flat conductor 2 is disposed below the fifth side wall portion 3w5 in the opposite direction Dz in the power supply portion 32, in the vicinity of the bent portion 3b between the fourth side wall portion 3w4 and the fifth side wall portion 3w5, the second part 312 is bent in a crank shape in the direction away from the main body portion of the flat conductor 2 in the opposite direction Dz (the upper side in the opposite direction Dz). In the fifth side wall portion 3w5, the second part 312 has the power supply portion 32 disposed thereon.

[0061] Also, as described above, when the protruding portion 2a is removed and the power supply portion 32 is disposed on the main body portion of the flat conductor 2, the second part 312 will extend linearly along the Dx-Dy plane direction across the entire area of the fourth side wall portion 3w4 and the entire area of the fifth side wall portion 3w5.

[0062] The third part 313 is adjacent to the second part 312 in the Dx-Dy plane direction. That is, along the Dx-Dy plane direction, the third part 313 is arranged successively in the order of the first part 311 and the second part 312. The third part 313 is arranged on the sixth side wall portion 3w6. Specifically, the third part 313 extends from the end of the sixth side wall portion 3w6 connected to the second part 312 along the Dx-Dy plane direction to a position closer to the side edge than the central portion of the sixth side wall portion 3w6. The length Ds3 of the third part 313 in the opposing direction Dz of the gap is longer than that of the first part 311 (Ds1).

[0063] The fourth part 314 is adjacent to the third part 313 in the Dx-Dy plane direction. That is, along the Dx-Dy plane direction, the fourth part 314 is arranged successively in the order of the first part 311, the second part 312, and the third part 313. The fourth part 314 is arranged on the sixth side wall portion 3w6. Specifically, the fourth part 314 extends along the Dx-Dy plane direction to a position closer to the side edge of the sixth side wall portion 3w6 with respect to the third part 313. The length Ds4 of the fourth part 314 in the opposing direction Dz of the gap is shorter than that of the third part 313 (Ds3).

[0064] The sixth side wall portion 3w6 has a grounding portion g1 between the fourth part 314 of the slot 31 and the side edge of the sixth side wall portion 3w6 along the Dx-Dy plane direction. The grounding portion g1 is connected to the flat conductor 2.

[0065] The fifth part 315 is adjacent to the first part 311 in the Dx-Dy plane direction. In other words, the fifth part 315 is arranged on the opposite side of the second part 312 with the first part 311 separated in the Dx-Dy plane direction. The fifth part 315 is arranged on the first side wall portion 3w1. Specifically, the fifth part 315 extends from near the central portion of the first side wall portion 3w1 connected to the first part 311 along the Dx-Dy plane direction to a position closer to the side edge of the first side wall portion 3w1. The length Ds5 of the fifth part 315 in the opposing direction Dz of the gap is shorter than that of the first part 311 (Ds1).

[0066] The first side wall portion 3w1 has a grounding portion g2 between the fifth portion 315 of the slot 31 and the side edge of the first side wall portion 3w1 along the Dx - Dy plane direction. The grounding portion g2 is connected to the flat plate conductor 2.

[0067] As described above, by bending a single flat plate member to form the bent conductor 3, the antenna device 1 can be easily formed. Further, by cutting off a part of the edge of the single flat plate member, the slot 31 can be easily formed. Therefore, in the antenna device 1, it is possible to improve productivity and further reduce costs.

[0068] Also, since the slot 31 is formed by juxtaposing a plurality of portions having different lengths in the direction Dz of the gap facing each other in the direction parallel to the flat plate conductor 2 (Dx - Dy plane direction), it is possible to provide a plurality of resonance points as a slot antenna. Therefore, in the antenna device 1, it is possible to achieve widebanding, multi - banding, and improvement of gain.

[0069] Also, as described above, the plurality of portions from the first portion 311 to the fifth portion 315 of the slot 31 have different lengths in the direction parallel to the flat plate conductor 2 (Dx - Dy plane direction) and different lengths in the direction Dz of the gap facing each other. By adjusting these lengths, it is possible to set to any band and any frequency in the widebanding and multi - banding of the antenna device 1.

[0070] Also, according to the configuration of the bent conductor 3 shown in FIG. 6, it is also possible to operate the bent conductor 3 itself as an antenna element such as a monopole antenna or an inverted - F antenna. Thereby, it is possible to provide a plurality of resonance points as an antenna device.

[0071] Also, the position of the feeding point 32 along the direction parallel to the flat plate conductor 2 (Dx - Dy plane direction) can be arbitrarily changed as appropriate. Thereby, the resonance frequency can be changed.

[0072] <Modification Example> FIG. 7 is a schematic perspective view of the antenna device 10 of the modified example. FIG. 8 is a top view of the antenna device 10 of FIG. 7. The antenna device 10 of the modified example includes a plurality of bent conductors 3 with respect to one flat conductor 2. In the present embodiment, the antenna device 10 includes two bent conductors 3. The two bent conductors 3 are respectively arranged at positions that are point-symmetrical with respect to the central portion of the flat conductor 2 when viewed from the facing direction Dz.

[0073] The flat conductor 2 is formed of a conductive sheet metal in the present embodiment. The plurality of bent conductors 3 are arranged opposite to each other on one flat conductor 2 and arranged side by side along the extending direction of the flat conductor 2.

[0074] Note that the flat conductor 2 may be constituted by a conductor pattern formed on a printed circuit board. Also, a plurality of pairs of flat conductors 2 and bent conductors 3 may be provided for one printed circuit board. For example, the antenna device 10 may be configured to include two pairs of flat conductors 2 and bent conductors 3 on one printed circuit board. In this case, a plurality of pairs consisting of the flat conductor 2 and the bent conductor 3 are arranged side by side along the extending direction of the flat conductor 2.

[0075] The plurality of bent conductors 3 each function as an independent antenna element and constitute the antenna device 10 as a whole. As an example, in the antenna device 10, the plurality of bent conductors 3 each function as an antenna element having directivity in a different direction. When two bent conductors 3 are arranged on one flat conductor 2, each bent conductor 3 functions as an antenna element having directivity in opposite directions.

[0076] As described above, in the antenna device 10, each of the plurality of bent conductors 3 may function as an antenna element having a different frequency band. Specifically, each of the plurality of bent conductors 3 is provided with a slot 31 having a different gap length in the direction parallel to the flat conductor 2 (Dx-Dy plane direction). Thereby, each of the plurality of bent conductors 3 can be made to function as an antenna element having a frequency band corresponding to the length of the slot 31. Therefore, the antenna device 10 can function as a multi-band antenna capable of transmitting and receiving radio waves in a plurality of frequency bands. Further, by switching or combining the outputs of the plurality of antenna elements, the antenna device 10 can also function as a space diversity antenna.

[0077] And according to the configuration of the antenna device 10, since the occupied areas of the two bent conductors 3 can be reduced, the free space Rv shown in FIG. 8 is generated. Thereby, the free space Rv can be effectively utilized for mounting the matching circuit, amplifier circuit, or other antenna elements of the antenna device 10.

[0078] <Matters Needing Attention, etc.> Various technical features disclosed as embodiments in this specification can be variously modified without departing from the gist of the technical creation. That is, the above embodiments are illustrative in all respects and not restrictive. The technical scope of the present invention is shown not by the description of the above embodiments but by the claims, and includes all modifications belonging to the meaning and scope equivalent to the claims. Also, the plurality of embodiments shown in this specification may be implemented in appropriate combination within the possible range.

Explanation of Reference Numerals

[0079] 1, 10 Antenna device 2 Flat conductor 3 Bent conductor 3b Bending part 3e End plate part 3e1 First end plate part 3e2 Second end plate part 3e3 Third end plate part 3e4 Fourth end plate part 3w Side wall part 3w1 First side wall part 3w2 Second side wall part 3w3 Third side wall part 3w4 Fourth side wall part 3w5 Fifth side wall part 3w6 Sixth side wall part 31 Slot 32 Power supply part 311 First part 312 Second part 313 Third part 314 Fourth part 315 Fifth part 331 First end plate part 332 Second end plate part 333 Third end plate part 334 Fourth end plate part Dz Opposite direction R1 First rectangular region R2 Second rectangular region Rv Empty region

Claims

1. A flat conductor and a bent conductor having a plurality of side wall portions disposed upright on the flat conductor, and the side wall portions being bent by a plurality of bent portions so as to be bent when viewed from the direction facing the flat conductor, comprising: a slot formed of a gap is provided between the flat conductor and the bent conductor, a region surrounded by the side wall portions is formed in an L shape when viewed from the facing direction, an antenna device.

2. The region surrounded by the side wall portions has a first rectangular region and a second rectangular region which are two rectangular regions when viewed from the facing direction, and the first rectangular region and the second rectangular region intersect at a right angle to form an L shape, The antenna device according to claim 1.

3. The slot is configured by a notch recessed in the facing direction such that a region of the bent conductor facing the flat conductor is separated from the flat conductor, The antenna device according to claim 1.

4. The slot has a plurality of portions with different lengths in the facing direction of the gap, The antenna device according to claim 1.

5. The slot has a first portion and a second portion adjacent to each other in a direction parallel to the flat conductor, In the second portion, the length in the facing direction of the gap is shorter than that of the first portion, and a power feeding portion for feeding power to the slot is disposed, The antenna device according to claim 4.

6. The slot has a third portion arranged in order of the first portion and the second portion in a direction parallel to the flat conductor, In the third portion, the length in the facing direction of the gap is longer than that of the first portion, The antenna device according to claim 5.

7. The slot has a fourth portion arranged in order of the first portion, the second portion, and the third portion in a direction parallel to the flat conductor, In the fourth portion, the length in the facing direction of the gap is shorter than that of the third portion, The antenna device according to claim 6.

8. The slot has a fifth portion arranged on the opposite side of the second portion with the first portion interposed therebetween in a direction parallel to the flat conductor, In the fifth portion, the length in the facing direction of the gap is shorter than that of the first portion, The antenna device according to claim 5.

9. The bent conductor is disposed on the opposite side of the flat conductor with respect to the facing direction and has an end plate portion extending in a direction parallel to the flat conductor, The antenna device according to claim 1.

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