JP6950159B2 - Antenna device - Google Patents

Description

The present invention relates to an antenna device.

The keyless entry system used to lock or unlock doors is mainly used in automobiles. In this keyless entry system, a device having a door of a vehicle or the like or an antenna device for transmission is mounted on the structure side. The main part of the antenna device includes an antenna main body including a core made of a magnetic material and a winding wound around the outer circumference of the core via a bobbin for accommodating the core, and a case for accommodating the antenna main body. have. In such an antenna device, it is required to increase the output (Patent Document 1).

Patent No. 50036888

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an antenna device capable of obtaining a larger output.

The above object is achieved by the following invention. That is,
The first antenna device of the present invention is used by being attached to a metal body, and has an antenna main body including a rod-shaped core and a conducting wire wound around the outer circumference of the rod-shaped core, and has a lower resistance than the metal body. A support formed integrally with a metal member having a metal member at least near both ends of the rod-shaped core and a metal body, a case for accommodating the antenna main body, and an outer shell of the case. It is provided with a base portion, and is characterized in that it is attached to a metal body via an abutment portion (however, it is sandwiched between a conducting wire and a metal member, and the conducting wire and the metal member are kept at a predetermined distance. Except for antenna devices further provided with porous members).
Further, the second antenna device of the present invention is used by being attached to a metal body, and has an antenna main body including a rod-shaped core and a conducting wire wound around the outer circumference of the rod-shaped core, and a resistance lower than that of the metal body. It is integrally formed with a metal member having a ratio and being arranged at a position that blocks at least the vicinity of both ends of the rod-shaped core and the metal body, a case for accommodating the antenna main body, and the outer shell of the case. It is characterized in that the abutment portion is provided, the attachment to the metal body is performed via the abutment portion, and a part or all of the metal members are arranged on the outside of the case.

An embodiment of a first antenna device of the present invention, a part of the metallic member or all, it is preferably arranged on the outside of the case.

In another embodiment of the antenna device of the first and second inventions, the metal member blocks at least the vicinity of both ends of the antenna body and the metal body, and faces both ends of the antenna body. It is preferable that they are arranged in such a manner.

In another embodiment of the antenna device of the first and second inventions, the metal member is arranged so as to block between the vicinity of one end side of the antenna main body and the metal body. , It is preferable to have a second member arranged so as to block between the vicinity of the other end side of the antenna main body and the metal body.

In another embodiment of the first and second antenna devices of the present invention, the shape of at least one member selected from the first member and the second member is parallel to the axial direction of the rod-shaped core, and It is preferable to have an L-shaped cross-sectional shape on a plane perpendicular to the surface on the side where the rod-shaped core of the metal body is arranged.

In another embodiment of the antenna device of the first and second inventions, it is preferable that the shape of at least one member selected from the first member and the second member is a bottomed cylinder.

In other embodiments of the first and second antenna devices of the present invention, it is preferable that at least one member selected from the first member and the second member has a cylindrical shape.

According to the present invention, it is possible to provide an antenna device capable of obtaining a larger output.

It is a schematic cross-sectional view which shows an example of the antenna device of this embodiment. It is a schematic cross-sectional view which shows another example of the antenna device of this embodiment. It is a schematic cross-sectional view which shows another example of the antenna device of this embodiment. It is a schematic cross-sectional view which shows another example of the antenna device of this embodiment. It is a schematic cross-sectional view which shows another example of the antenna device of this embodiment.

FIG. 1 is a schematic cross-sectional view showing an example of the antenna device of the present embodiment, and is a diagram showing a state in which the antenna device is attached to a plate-shaped metal body. The antenna device 10A (10) shown in FIG. 1 is, for example, an antenna device for transmission of a short-range communication system in the LF band (30 kHz to 300 kHz), and is mainly used as a keyless entry system for remotely controlling the locking and unlocking of vehicle doors. Can be used. The antenna device 10A has an antenna main body portion 20, a case 30, and an abutment portion 40 integrally formed with an outer shell portion of the case 30. The antenna device 10 is attached to the surface (mounting surface 50A) of the plate-shaped metal body 50 via the abutment portion 40. The antenna device 10A can be fixed to the mounting surface 50A by using, for example, an adhesive or tape. Further, the metal body 50 is usually used as a member constituting a door panel constituting a door of a vehicle or the like, and in this case, the mounting surface 50A constitutes a surface on the back surface side of the door panel.

Here, the antenna main body 20 is wound around the outer circumference of the rod-shaped core 22 (that is, the outer peripheral surface of the bobbin 24) via the rod-shaped core 22, the cylindrical bobbin 24 for accommodating the rod-shaped core 22, and the bobbin 24. It has a lead wire 26. Further, the antenna main body 20 is housed in a bottomed cylindrical case 30 so that the axial direction A of the rod-shaped core 22 is parallel to the mounting surface 50A of the metal body 50. The opening 32 of the case 30 that houses the antenna main body 20 is covered with a lid member 34.

Further, in the space inside the case 30, a metal terminal 60 is arranged between the inner wall surface of the case 30 and the antenna main body 20 in the vicinity of the opening 32 side. The metal terminal 60 penetrates the lid member 34 and extends to the outside of the lid member 34, one end of which is connected to the conducting wire 26 and the other end of which is connected to the external connection terminal 62. A tubular grommet 70 is attached to the opening 32 side of the case 30 so as to cover the lid member 34, the metal terminal 60 exposed to the outside of the lid member 34, and the external connection terminal 62. If necessary, an electronic element such as a chip capacitor may be further connected to the metal terminal 60.

The rod-shaped core 22 is made of a magnetic material, and for example, a member made by compression molding fine powder of Mn—Zn-based ferrite or other amorphous magnetic material can be appropriately used. Further, the conducting wire 26 is a member having a core wire made of a conductive material such as copper and an insulating material covering the surface of the core wire, and the metal terminal 60 and the external connection terminal 62 are made of a conductive member such as copper. Members can be used as appropriate. Further, as the bobbin 24, the case 30, the lid member 34, and the abutment portion 40, members made of a resin material are used. For example, as the bobbin 24, a member injection-molded using PBT (polybutylene terephthalate) can be used, and as the case 30 and the abutment portion 40, a member injection-molded using PP (polypropylene) can be used. Can be done.

Further, the metal member 100 is arranged at a position that shields the vicinity of both ends of the rod-shaped core 22 from the metal body 50. The metal member 100 is composed of a flat plate-shaped first member 102A and a flat plate-shaped second member 102B. Then, the first member 102A is arranged near one end side of the rod-shaped core 22 so that the front and back surfaces are parallel to the axial direction A, and the front and back surfaces are parallel to the axial direction A near the other end side of the rod-shaped core 22. The second member 102B is arranged so as to form. Here, the first member 102A is fixed to the outer wall surface of the outer shell member 30S constituting the case 30 by using an adhesive, tape, or the like, and the second member 102B is provided in the outer shell member 30S. It is inserted into the gap and fixed.

Further, the width of the metal member 100 is larger than the width of the coil 26C formed by winding the conducting wire 26, so that both ends of the metal member 100 in the width direction are located outside the both ends of the coil 26C in the width direction. It is particularly preferable that the metal member 100 is arranged. Here, the width direction of the metal member 100 and the coil 26C means a direction orthogonal to the axial direction A of the rod-shaped core 22 and parallel to the mounting surface 50A.

If the metal member 100 is made of a metal material having a resistivity lower than that of the metal body 50, a member made of a known metal material can be appropriately used. For example, when the material constituting the metal body 50 is an iron-based material (iron or iron alloy) containing iron as a main component such as stainless steel, the metal member 100 is an aluminum-based material (aluminum) containing aluminum as a main component. Alternatively, an aluminum alloy) or a copper-based material containing copper as a main component (copper or copper alloy) can be used. When the material constituting the metal body 50 is an aluminum-based material, a copper-based material can be used as the metal member 100.

Next, the reason why a larger output can be obtained in the antenna device 10 of the present embodiment will be described. First, in the state where the metal member 100 is removed from the antenna device 10A shown in FIG. 1, the magnetic flux generated when a current is passed through the coil 26C causes an eddy current in the metal body 50 when it passes through the metal body 50. appear. Therefore, when the resistivity of the metal body 50 is high, the impedance of the antenna system as a whole becomes large. Therefore, when a constant voltage is applied to the coil 26C, the current flowing through the coil 26C also decreases (or, when a constant current is applied, the voltage increases). Further, when the current flowing through the coil 26C decreases, the magnetic flux generated by the coil 26C also decreases, and as a result, the output of the coil 26C also decreases.

However, in the antenna device 10 of the present embodiment, the metal member 100 having a resistivity lower than that of the metal body 50 is arranged at a position that blocks at least the vicinity of both ends of the rod-shaped core 22 and the metal body 50. .. Then, the metal member 100 arranged at this position can effectively block the magnetic flux generated from the coil 26C from reaching the metal body 50. Therefore, while a large amount of eddy current is generated in the metal member 100, the amount of eddy current generated in the metal body 50 is reduced. As a result, the impedance of the antenna system as a whole decreases. Therefore, when a constant voltage is applied to the coil antenna, the current flowing through the coil 26C increases (or when a constant current is applied, the increase in voltage is suppressed). When the current flowing through the coil 26C increases, the magnetic flux generated by the coil 26C also increases, and the output of the coil 26C increases.

In the antenna device 10, the present inventors measured the static characteristics and the dynamic characteristics of the antenna device 10 with the resonance frequency and the input current being substantially constant between the case where the metal member 100 is removed and the case where the metal member 100 is used. went. As a result, although there are differences in the values depending on the material, shape, arrangement position, etc. of the metal member 100, in any case, the coil 26C is used when the metal member 100 is used as compared with the case where the metal member 100 is removed. It was confirmed that the impedance of the metal decreases as the resistance value of the metal decreases. At this time, the reduction rate of the resistance value and the impedance was several% to several tens of%.

In the example shown in FIG. 1, a part of the metal member 100 (first member 102A) is arranged on the outer wall surface of the outer shell member 30S constituting the case 30, and the other part (second member 102B) is the outer shell. It is arranged in the member 30S. However, the metal member 100 can be arranged at any position as long as it is arranged at a position that blocks at least the vicinity of both ends of the rod-shaped core 22 and the metal body 50. For example, a part of the metal member 100. Alternatively, all of them may be arranged between (i) the inner wall surface inside the case 30 and the antenna main body 20, and (ii) outside the case 30 as in the first member 102A illustrated in FIG. It may be arranged, or it may be arranged in the outer shell member 30S constituting the case 30, as in the second member 102B illustrated in FIG. 1 (iii).

Here, from the viewpoint of the arrangement position of the metal member 100 capable of most effectively blocking the magnetic flux generated by the coil 26C, it is considered most ideal to arrange the metal member 100 at the position shown in (i). However, arranging the metal member 100 in an extremely limited space in the case 30 tends to cause a great limitation in the shape of the metal member 100 that can be arranged in the case 30 due to the design of the antenna device 10. This is because when the metal member 100 having a more complicated shape is used, the shape design of the case 30 becomes extremely difficult both technically and costly. Therefore, as a practical problem, since the shape that can be selected as the metal member 100 is limited, a shape that can more effectively block the magnetic flux generated by the coil 26C as illustrated in FIGS. 3 to 5 described later is selected. It becomes difficult to do. Therefore, as a result, it tends to be difficult to significantly improve the output of the antenna device 10 as a whole.

On the other hand, when the metal member 100 is arranged at the position shown in (ii), the shape of the metal member 100 that can be arranged outside the case 30 is unlikely to be restricted due to the design of the antenna device 10, and various shapes are formed. The metal member 100 can be easily used, and for example, it is easy to select a shape capable of more effectively blocking the magnetic flux generated by the coil 26C as illustrated in FIGS. 3 to 5 described later. Considering these points, it is most preferable to arrange a part, more preferably all of the metal member 100 at the position shown in (ii).

Further, among the parts constituting the antenna device 10, the shapes and structures of the members other than the rod-shaped core 22 and the metal member 100 are not limited to the example shown in FIG. It can be appropriately selected according to the shape and structure of the core 22 and the metal member 100 and the relative arrangement of these two members.

Further, in the example shown in FIG. 1, the two members (first member 102A and second member 102B) used as the metal member 100 are both plate-shaped members having a rectangular plane, but the shape of the metal member 100. Is not limited to this, and various shapes can be appropriately selected. 2 to 5 are schematic cross-sectional views showing another example of the antenna device of the present embodiment. In FIGS. 2 to 5, the description of the rod-shaped core 22, the metal member 100, and other members other than the metal body 50 is omitted.

In the antenna device 10B (10) of the present embodiment shown in FIG. 2, the front and back surfaces are parallel to the axial direction A at a position blocking between the entire axial direction A of the rod-shaped core 22 and the metal body 50. A metal member 104 (100) made of a plate-shaped member having a rectangular flat surface is arranged. The length of the metal member 104 in the direction parallel to the axial direction A (longitudinal direction) is larger than the length of the rod-shaped core 22 in the axial direction A. Further, the metal member 104 is arranged between the rod-shaped core 22 and the metal body 50 so that both ends of the metal member 104 in the longitudinal direction are located outside the both ends of the rod-shaped core 22. That is, the metal member 104 can block not only between the vicinity of both ends of the rod-shaped core 22 and the metal body 50, but also between the central portion of the rod-shaped core 22 and the metal body 50.

For reference, Table 1 shows the results of evaluating the static characteristics and the dynamic characteristics of the antenna device 10B shown in FIG. 2 and the antenna device obtained by removing the metal member 104 from the antenna device 10. In Table 1, a Mn—Zn-based ferrite core (length 62 mm × width 8.0 mm × thickness 3.2 mm) is used as the rod-shaped core 22, and a plate-shaped member (length) made of an aluminum alloy is used as the metal member 104. 70 mm x width 15 mm x thickness 1 mm), a stainless steel plate (thickness 0.5 mm) is used as the metal body 50, the distance between the rod-shaped core 22 and the mounting surface 50A of the metal body 50 is 2.5 mm, and the metal member 104 and the metal. The results obtained by measuring the distance of the body 50 from the mounting surface 50A to 9.0 mm are shown.

As shown in Table 2, the antenna device 10B of the present embodiment shown in FIG. 2 is confirmed to have a 22% reduction in resistance value R as compared with the antenna device in which the metal member 104 is removed from the antenna device 10B shown in FIG. Then, a decrease of -40% was confirmed in the impedance value | Z |.

In the antenna device 10C (10) of the present embodiment shown in FIG. 3, the metal member 100 is composed of the first member 106A and the second member 106B. The first member 106A and the second member 106B are parallel to the axial direction A of the rod-shaped core 22 and perpendicular to the mounting surface 50A (the surface on the side where the rod-shaped core 22 of the metal body 50 is arranged). The cross-sectional shape on the plane forming the above is L-shaped. The cross-sectional shape of the second member 106B shows a shape in which "L" is horizontally inverted in FIG. 2, but when the right side in the axial direction A is viewed as the downward side in the drawing, L Form a character.

The first member 106A and the second member 106B are provided on the square first flat plate portion 120 and one end side of the first flat plate portion 120, and the second flat plate portion 122 orthogonal to the first flat plate portion 120. It is composed of and. Then, between the rod-shaped core 22 and the metal body 50, the first flat plate portion 120 whose front and back surfaces are parallel to the axial direction A blocks the vicinity of the end portion of the rod-shaped core 22 and the metal body 50. positioned. Further, the second flat plate portion 122 is positioned so that the surface (opposing surface 122S) of the second flat plate portion 122 on the side where the first flat plate portion 120 is provided and the end surface 22E of the rod-shaped core 22 face each other. .. That is, in the example shown in FIG. 3, the metal member 100 is arranged so as to block the vicinity of both ends of the antenna main body 20 and the metal body 50 and face both end surfaces of the antenna main body 20. ..

In the antenna device 10D (10) of the present embodiment shown in FIG. 4, the metal member 100 is composed of the first member 108A (100) and the second member 108B (100). The shapes of the first member 108A and the second member 108B are bottomed cylinders. Further, the first member 108A is arranged on one end side of the rod-shaped core 22 so as to surround one end of the rod-shaped core 22, and the second member 108B is arranged so as to surround the other end of the rod-shaped core 22. It is arranged on the other end side of 22. Therefore, of the side wall portions 130 constituting the outer peripheral surfaces of the first member 108A and the second member 108B, the side wall portion 130 located on the metal body 50 side of the rod-shaped core 22 is close to the end portion of the rod-shaped core 22 and the metal body. It will be positioned so as to block the space between the 50 and the 50. Further, the inner bottom surface 132S of the bottom wall portion 132 forming the bottom surface of the first member 108A and the second member 108B faces the end surface 22E of the rod-shaped core 22. That is, similar to the example shown in FIG. 3, in the example shown in FIG. 4, the metal member 100 blocks the vicinity of both ends of the antenna main body 20 and the metal body 50, and both end faces of the antenna main body 20. It is arranged so as to face the antenna.

In the antenna device 10E (10) of the present embodiment shown in FIG. 5, the metal member 100 is composed of the first member 110A (100) and the second member 110B (100). The first member 110A and the second member 110B have a shape (cylindrical shape) in which the bottom wall portion 132 is removed from the bottomed tubular first member 108A and the second member 108B shown in FIG. The first member 110A is arranged on one end side of the rod-shaped core 22 so as to surround one end of the rod-shaped core 22, and the second member 110B is arranged so as to surround the other end of the rod-shaped core 22. It is arranged on the other end side. Therefore, of the side wall portions 130 constituting the outer peripheral surfaces of the first member 110A and the second member 110B, the side wall portion 130 located on the metal body 50 side of the rod-shaped core 22 is close to the end portion of the rod-shaped core 22 and the metal body. It will be positioned so as to block the space between the 50 and the 50.

As illustrated in FIGS. 1 to 5, members having various shapes can be used as the metal member 100. Further, when the metal member 100 is composed of two separate and independent members as illustrated in FIGS. 1 and 3 to 5, the shape of at least one of the two members constituting the metal member 100 is (1). i) As illustrated in FIG. 1, it may have a flat plate shape. However, since the magnetic flux generated by the coil 26C can be cut off more effectively, the shape of at least one member is parallel to the axial direction A of the rod-shaped core 22 and is parallel to the axial direction A of the rod-shaped core 22, as illustrated in FIG. , Has an L-shaped cross-sectional shape on a plane perpendicular to the side surface (mounting surface 50A) on which the rod-shaped core 22 of the metal body 50 is arranged, or (ii) a bottomed cylinder as illustrated in FIG. It is preferable to form a shape or to form a cylinder as illustrated in FIG. 5 (iii).

Further, when the metal member 100 is composed of two separate and independent members, both of the two members may have the same shape as illustrated in FIGS. 1, 3 to 5. The shapes of the two members may be different from each other. The combination of shapes when the shape of one member and the shape of the other member are different from each other is not particularly limited. For example, as a combination of the shape of one member and the shape of the other member, <a> ( A combination of a bottomed cylinder (Fig. 4) and a cylinder (Fig. 5)), a combination of <b> (bottomed cylinder (Fig. 4), L-shaped cross section (Fig. 3)), <c> (bottomed) Examples include a combination of a cylindrical shape (FIG. 4) and a flat plate shape (FIG. 3). In these three types of combinations shown in <a> to <c>, the shape of the member arranged on the end side (first end side) of the rod-shaped core 22 on the side where the metal terminal 60 is arranged has a cylindrical shape and a cross section. It is preferable that the member has an L-shape or a flat plate shape, and the shape of the member arranged on the end (second end) side opposite to the first end is a bottomed cylinder. Since the structure of the antenna device 10 near the first end side on which the metal terminal 60 is arranged tends to be complicated, it may be difficult to adopt a bottomed cylindrical shape as the shape of one or the other member constituting the metal member 100. Because there is.

Further, in the example shown in FIG. 3, a metal member 100 having a structure in which the first flat plate portion 120 is extended in the axial direction A and the first member 106A and the second member 106B are connected, that is, one first member. The metal member 100 may have a structure in which the second flat plate portion 122 is provided at both ends of the one flat plate portion 120. Similarly, in the example shown in FIG. 4, the metal member 100 having a structure in which the portion of the side wall portion 130 on the metal body 50 side is extended in the axial direction A and the first member 108A and the second member 108B are connected. In the example shown in FIG. 5, a metal member having a structure in which a portion of the side wall portion 130 on the metal body 50 side is extended in the axial direction A and the first member 110A and the second member 110B are connected to each other. It may be 100.

Of the magnetic flux components generated by the coil 26C, the magnetic flux components that generate an eddy current that causes a decrease in the output of the coil 26C in the metal body 50 can be roughly classified into (1) from the end side of the rod-shaped core 22. A component that curves sharply with respect to the axial direction A toward the metal body 50 side or a component in the opposite direction (hereinafter referred to as "first magnetic flux component") and (2) from the end side of the rod-shaped core 22. , There is a component that gently curves with respect to the axial direction A toward the metal body 50 side, or a component in the opposite direction (hereinafter, referred to as “second magnetic flux component”).

Here, the metal member 100 (members 102A, 102B, 104, 110A, 110B) shown in FIGS. 1, 2 and 5 can effectively block the first magnetic flux component, but can effectively block the second magnetic flux component. It is difficult to block sufficiently. Further, if the second magnetic flux component is also effectively cut off, the metal member 100 (members 102A, 102B, 104, 110A, 110B) must be significantly extended along the axial direction A. In this case, the antenna devices 10A, 10B, and 10E become large in size, which is not practical. However, in the metal member 100 (members 106A, 106B, 108A, 108B) shown in FIGS. 3 and 4, the second magnetic flux component can be effectively cut off while suppressing the increase in size of the antenna devices 10C and 10D. Is more advantageous.

Further, the internal structure of the door of a vehicle or the like varies depending on the type of the door, and the first structure constituting a part of the door is located in the vicinity of the mounting surface 50A of the metal body 50 (first metal body). A second metal body (eg, a beam to reinforce the door), which is made of substantially the same material as the metal body of the above, may be further arranged. Therefore, depending on the mounting position of the antenna device 10 and the arrangement position of the second metal body, the presence of the second metal body may cause a decrease in the output of the coil 26C. However, in the case of the antenna devices 10C, 10D, and 10E provided with the metal members 100 (members 106A, 106B, 108A, 108B, 110A, 110B) shown in FIGS. 3 to 5, an eddy current is generated in the second metal body. It also becomes easy to effectively block the magnetic flux component to be caused. In particular, in the case of the antenna device 10D provided with the metal members 100 (members 108A and 108B) shown in FIG. 4, the second metal body is reliably arranged at any position near the mounting surface 50A. In addition, the magnetic flux component that generates an eddy current in the second metal body can be effectively cut off.

That is, the antenna device 10D shown in FIG. 4 is extremely advantageous in that a larger output can be reliably obtained regardless of the internal structure of the door to be mounted. Further, the shape of the metal member 100 is selected according to the internal structure of the door, particularly the arrangement position of the second metal body, and each part such as the case 30 of the antenna device 10 according to the metal member 100 adopting the predetermined shape. It is also easy to save the trouble of drastically redesigning the structure of the door.

On the other hand, as described above, the metal member 104 shown in FIG. 2 is in that not only the generation of the eddy current in the first metal body 50 but also the generation of the eddy current in the second metal body becomes easy. A more complicated and three-dimensional shape such as the metal member 100 (members 106A, 106B, 108A, 108B, 110A, 110B) shown in FIGS. 3 to 5 is used rather than one plate-shaped member having such a simple shape. Is advantageous. However, when the shape of the metal member 100 is a complicated and three-dimensional shape, when the metal member 100 is composed of only one member, the metal member 100 is difficult to be molded and the antenna device 10 is formed. The structure and assembly process of the antenna are likely to be complicated. Therefore, the degree of freedom in designing the antenna device 10 tends to decrease. However, such a demerit can be significantly suppressed by using two separate and independent members in combination as the metal member 100 as shown in FIGS. 3 to 5.

10, 10A, 10B, 10C, 10D, 10E: Antenna device 20: Antenna body 22: Rod-shaped core 22E: End face 24: Bobbin 26: Conductor 26C: Coil 30: Case 30S: Outer shell member 32: Opening 34: Lid Member 40: Abutment 50: Metal body 50A: Mounting surface 60: Metal terminal 62: External connection terminal 70: Grommet 100, 104: Metal member 102A, 104A, 106A, 108A, 110A: First member (one of the metal members) Department)
102B, 104B, 106B, 108B, 110B: Second member (part of metal member)
120: First flat plate portion 120S: Facing surface 122: Second flat plate portion 130: Side wall portion 132: Bottom wall portion 132S: Inner bottom surface

Claims (8)

Used by being attached to a metal body
An antenna main body including a rod-shaped core and a conducting wire wound around the outer circumference of the rod-shaped core, and
A metal member having a resistivity lower than that of the metal body and arranged at a position that blocks at least the vicinity of both ends of the rod-shaped core and the metal body.
A case for storing the antenna body and
An abutment portion integrally formed with the outer shell portion of the case is provided.
An antenna device characterized in that attachment to the metal body is performed via the abutment portion (provided that the antenna device is sandwiched between the conductor and the metal member, and the conductor and the metal member are kept at a predetermined distance. Unless further provided with a porous member to retain). Used by being attached to a metal body
An antenna main body including a rod-shaped core and a conducting wire wound around the outer circumference of the rod-shaped core, and
A metal member having a resistivity lower than that of the metal body and arranged at a position that blocks at least the vicinity of both ends of the rod-shaped core and the metal body.
A case for storing the antenna body and
An abutment portion integrally formed with the outer shell portion of the case is provided.
The attachment to the metal body is performed via the abutment portion,
An antenna device characterized in that a part or all of the metal member is arranged outside the case. The antenna device according to claim 1, wherein a part or all of the metal member is arranged outside the case. Claim 1 is characterized in that the metal member blocks at least the vicinity of both ends of the antenna main body and the metal body, and is arranged so as to face both end faces of the antenna main body. The antenna device according to any one of 3 to 3. The first member in which the metal member is arranged so as to block between the vicinity of one end side of the antenna main body and the metal body, the vicinity of the other end side of the antenna main body, and the metal. The antenna device according to any one of claims 1 to 4, wherein the antenna device has a second member arranged so as to block the space from the body. The shape of at least one of the first member and the second member is parallel to the axial direction of the rod-shaped core, and the surface of the metal body on the side where the rod-shaped core is arranged. The antenna device according to claim 5, wherein the antenna device has an L-shaped cross-sectional shape on a vertically formed plane. The antenna device according to claim 5, wherein the shape of at least one of the first member and the second member is a bottomed cylinder. The antenna device according to claim 5, wherein the shape of at least one of the first member and the second member is tubular.

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