JP2023034238A - Antenna device and manufacturing method for the same - Google Patents

Abstract

To make it possible to have the same toughness as that of a structure while suppressing the workload.SOLUTION: An antenna device 100 includes a first antenna part 11 provided on an entrance/exit of a structure and composed of a metal plate formed with a slit hole SHL and a connecting part 12, which is a conductive member and connected to a side of the slit hole SHL or an area thinner than the other area including the slit hole SHL in the metal plate.SELECTED DRAWING: Figure 1

Description

The present invention relates to an antenna device and a method of manufacturing an antenna device.

In the field of IoT (Internet of Things), where the market is expected to expand, it is known to use a communication system of LPWA (Low Power Wide Area) (Non-Patent Document 1). In addition, radio waves such as LPWA, Wi-Fi (registered trademark), 5G, 6G, etc. travel in a straight line and have a short communication distance, so it is desired to install a large number of antennas.

Therefore, in order to realize the installation of a large number of antennas, it is desired to attach antennas to existing structures regardless of whether they are indoors or outdoors. At this time, it is required that the appearance of the structure is not spoiled by attaching the antenna to the structure. For this reason, glass antennas that have an inconspicuous appearance and can be retrofitted have been provided (Non-Patent Document 2).

In addition, by incorporating an antenna into a special steel manhole cover, a technology has been developed to attach the antenna to the road surface so as not to interfere with vehicles while suppressing damage to the antenna from external forces (Non-Patent Document 3). ).

NTT West, “Commercialization of LoRaWAN (registered trademark) for IoT Business Expansion,” NTT Technical Journal, October 2018, pp.44-47 AGC, "Development of AGC's 'Glass Antenna that Converts Windows into a Base Station' 5G Completion", [online], [Searched on July 5, 2021], Internet <URL: https://www.agc .com/news/detail/1200821_2148.html＞ Meidensha, ``Manhole antenna for real-time monitoring of pipes'', [online], [searched on July 5, 2021], Internet <URL: https://www.meidensha.co.jp/catalog/bb/BB524 -3291.pdf＞

However, when an antenna made of a brittle material such as the glass antenna described above is attached to a structure made of metal or reinforced concrete, the antenna cannot withstand an external force equivalent to that which the structure can withstand. can't Therefore, even in situations where the structure is not damaged by external forces, the antenna may be susceptible to damage. Therefore, when an antenna is attached to a structure, it is required to have toughness equivalent to the structure to which it is attached. In addition, since the antenna has the same toughness as the structure, the method of building the antenna in the structure as described above involves a high workload and a high cost.

SUMMARY OF THE INVENTION An object of the present invention, which has been made in view of such circumstances, is to provide an antenna device and a method of manufacturing an antenna device that can have toughness equivalent to that of a structure while suppressing high workload and high cost. to provide.

An antenna device according to one embodiment includes a first antenna section configured by a metal plate having a slit hole formed at an entrance of a structure, and a conductive member, one end of which is a connection part that is thinner than the side surface of the slit hole or other area of the metal plate and is connected to the area including the slit hole.

A method for manufacturing an antenna device according to one embodiment comprises the steps of: forming a slit hole in a metal plate arranged in a structure; attaching one end of a cable to a conductive plate; and attaching the conductive plate to a side surface, or a region including the slit hole, which is thinner than other regions.

According to the present invention, it is an object of the present invention to provide an antenna device and a method of manufacturing an antenna device that can have toughness equivalent to that of a structure while suppressing a workload.

1 is a schematic diagram showing an example of an antenna device according to a first embodiment; FIG. It is a figure which shows the iron cover shown in FIG. 1 in detail. FIG. 3 is a top view of the iron lid shown in FIG. 2; 3 is a bottom view of the iron lid shown in FIG. 2; FIG. 2 is a diagram showing VSWR of the antenna device shown in FIG. 1; FIG. 4 is a flow chart showing an example of a method for manufacturing the antenna device according to the first embodiment; It is a figure which shows the 1st modification of a part of iron cover shown in FIG. 3 is a view showing a second modification of part of the iron lid shown in FIG. 2; FIG. It is a schematic diagram showing an example of an antenna device concerning a 2nd embodiment. 9 is a flow chart showing an example of a method for manufacturing an antenna device according to a second embodiment;

<<First Embodiment>>
A first embodiment of the present invention will be described in detail below with reference to the drawings.

<Configuration of Antenna Device>
An example of the configuration of the antenna device 100 according to the first embodiment of the present invention will be described.

As shown in FIG. 1, the antenna device 100 transmits and receives electrical signals to and from the internal device 200 . In this example, the antenna device 100 may transmit and receive electrical signals to and from the internal device 200 through wired communication.

Also, the antenna device 100 transmits and receives electrical signals to and from the external device 300 by wireless communication. In this example, the antenna device 100 transmits and receives electrical signals to and from the external device 300 via a wide area network such as LTE (Long Term Evolution) or LoRaWAN (Long Range Wide Area Network).

The internal device 200 receives an electrical signal transmitted from the antenna device 100 and includes a transmission/reception unit that transmits the electrical signal to the antenna device 100, a control unit that controls the electrical signal, a communication device (first communication device ). The internal device 200 is arranged on the inside S1 side of the structure.

The external device 300 is, for example, a communication device (second communication device) such as a server that manages various information acquired by the internal device 200 . The external device 300 is arranged on the outside S2 side of the structure.

The structure in this embodiment is a structure for demarcating an underground space. The structure is a manhole 400 buried in the ground A, for example. The structure is made of metal, concrete, resin concrete, or the like.

The manhole 400 includes a neck 41 , a housing 42 and an iron lid 43 . The neck portion 41 and the housing 42 are made of, for example, reinforced concrete. The neck 41 may be generally cylindrical and the space defined by the neck 41 communicates with the exterior S2 of the structure. The housing 42 can have a substantially rectangular parallelepiped shape. Also, the space defined by the neck portion 41 and the space defined by the housing 42 communicate with each other.

The iron cover 43 is a member that covers the boundary (entrance of the manhole 400) between the space on the inside S1 side defined by the structure and the space on the outside S2 side. In the example shown in FIG. 1, the iron lid 43 is arranged on the neck portion 41 on the outside S2 side. In one example, as shown in FIG. 2, the iron lid 43 includes a plate surface portion 431 having a plate surface shape. Also, as shown in FIGS. 3A and 3B, the surface of the plate surface portion 431 can be circular.

As shown in FIGS. 2, 3A, and 3B, the iron lid 43 may further include a convex portion 432 that is sufficiently smaller than the plate surface portion 431. As shown in FIG. The convex portion 432 is arranged on the surface of the plate surface portion 431, and may be arranged on both sides of the surface, or may be arranged on one side of the surface. In addition, in FIGS. 3A and 3B, only some of the convex portions 432 are given reference numerals, and the reference numerals of the other convex portions 432 are omitted.

For example, as shown in FIG. 3A, the iron lid 43 may have a plurality of substantially square convex portions 432a when viewed from the outside S2 side. Also, the iron lid 43 may have a substantially circular protrusion 432b when viewed from the outside S2 side. Further, the iron lid 43 may be formed with a hole HL sufficiently smaller than the iron lid 43 and penetrating the iron lid 43 .

In addition, as shown in FIG. 3B, the iron cover 43 may have a convex portion 432 on the inner S1 side surface. Specifically, the iron lid 43 has two protrusions 432c extending in one direction (y-axis direction) on the surface on the inner S1 side, and extends in a direction (x-axis direction) perpendicular to the one direction. may have two protrusions 432d. A parallel cross may be formed by two protrusions 432c extending in the x-axis direction and two protrusions 432d extending in the y-axis direction. The grid is a member that supports the weight loaded on the iron lid 43 arranged on the structure.

The iron lid 43 is formed with a slit hole SHL which is a rectangular hole penetrating the iron lid 43 . When the current flowing around the slit hole SHL in the iron lid 43 changes, the magnetic field around the iron lid 43 changes, so that the iron lid 43 transmits radio waves and transmits an antenna (to the antenna section 11 described later). equivalent).

The slit hole SHL has a rectangular shape when viewed from the normal direction (z-axis direction) of the surface of the iron lid 43 . The slit holes SHL may be formed by cutting a metal plate in which the slit holes SHL are not formed, or by molding the metal plate so as to form the slit holes SHL. good.

The slit hole SHL may be formed in the floor slab portion of the iron lid 43 . The floor slab portion is a portion that does not come into contact with other members when the iron lid 43 is installed on the structure. Since the impact of the bearing force on the floor slab is small, it is possible to suppress damage to the area around the slit hole SHL in the antenna section 11 . In the example shown in FIGS. 2 and 3B, the floor slab portion is a portion of the iron lid 43 where the projecting portions 432c and 432d that form the grid are not provided.

As shown in FIGS. 3A and 3B, the slit hole SHL may be formed at a position separated from the protrusion 432 by 5 mm or more. Specifically, the slit hole SHL is formed at a distance of 5 mm or more (5 mm in FIG. 3A and 7 mm in FIG. 3B) from the convex portion 432 in the direction (y-axis direction) in which the long side of the slit hole SHL extends, and the slit It may be formed so as to be separated from the projection 432 by 5 mm or more (5 mm in FIGS. 3A and 3B) in the direction in which the short side of the hole SHL extends (x-axis direction). The effect of being 5 mm or more away from the slit hole SHL convex portion 432 will be described later with reference to FIG.

Similarly, the slit hole SHL may be formed so as to be separated from the hole HL by 5 mm or more.

Also, the size of the slit hole SHL can be set to a value corresponding to the wavelength λ of the radio wave based on the electrical signal transmitted/received to/from the internal device 200 and the external device 300 . For example, the length y_shl of the long side of the slit hole SHL can be 0.7λ or more and 0.8λ or less. Also, the length x_shl of the short side of the slit hole SHL can be 0.02λ or more and 0.05λ or less. Also, the height z1 (see FIG. 2) of the slit hole SHL can be set to 9 mm as an example regardless of the wavelength λ. Since the slit hole SHL is formed sufficiently smaller than the iron lid 43, the strength of the iron lid 43 is less affected by the slit hole SHL.

Also, the slit hole SHL may be filled with an insulating material such as resin. Thereby, the antenna device 100 can suppress passage of air, water, etc. through the slit hole SHL. As a result, the antenna device 100 can prevent rust on the surface of the iron lid 43 defining the slit hole SHL.

Also, the slit hole SHL may not be filled with an insulating material such as resin. In such a configuration, the surface of the iron lid 43 defining the slit hole SHL may be subjected to rust prevention treatment. As a result, the antenna device 100 can maintain air permeability while preventing rust on the surface of the iron lid 43 that defines the slit holes SHL.

A plurality of slit holes SHL may be formed in the iron lid 43 . As a result, the periphery of each of the slit holes SHL transmits a plurality of radio waves, so the iron lid 43 functions as an antenna that transmits a plurality of radio waves. Thereby, compared with the case where one slit hole SHL is formed, more radio waves can be transmitted per unit time, and the communication speed is improved. Further, by appropriately designing the positions and directions of the plurality of slit holes SHL, the antenna device 100 can better control the directivity of radio waves based on the electrical signals transmitted from the iron lid 43 . Along with this, it is possible to suppress the radio wave attenuation that occurs remarkably in the case of parasitic relay in particular.

The antenna device 100 includes an antenna section (first antenna section) 11 and a connection section 12 .

The antenna section 11 is configured by a metal plate provided with a slit hole SHL, which is disposed at the entrance/exit of the structure. The metal plate can be, for example, the plate surface portion 431 of the iron cover 43 provided in the manhole 400 described above. When the current flowing around the slit hole SHL in the antenna section 11 changes, the magnetic field around the antenna section 11 changes, and the antenna section 11 transmits radio waves. The antenna section 11 can function as an active antenna and can also function as a passive antenna.

Moreover, a convex portion may be formed on the surface of the metal plate forming the antenna portion 11 . In the above-described example in which the metal plate is the plate surface portion 431 of the iron lid 43 , the convex portion formed on the surface of the metal plate is the convex portion 432 of the iron lid 43 . Therefore, as described with reference to the example of the iron lid 43, the slit hole SHL formed in the antenna section 11 is positioned at a distance of 5 mm or more from the convex portion on the surface of the metal plate forming the antenna section 11. may be formed.

The connection portion 12 is a conductive member, and one end of the connection portion 12 is connected to the periphery of the slit hole SHL in the metal plate forming the antenna portion 11 . In this example, the periphery of the slit hole SHL is the side surface of the slit hole SHL. The other end of the connection portion 12 is connected to an internal device 200 that transmits and receives electrical signals. The connection 12 comprises a cable, which may be a coaxial cable 121, for example. The connecting portion 12 may further include a conductive plate 122 to which one end of the cable is connected.

One end of the cable is connected around the slit hole SHL in the metal plate forming the antenna section 11 . In configurations where the cable is coaxial cable 121, coaxial cable 121 includes an inner conductor 121a and an outer conductor 121b surrounding the periphery of inner conductor 121a.

As shown in FIG. 2, one end of each of the inner conductor 121a and the outer conductor 121b of the coaxial cable 121 is connected to the metal plate forming the antenna section 11 around the slit hole SHL. Specifically, one end of the inner conductor 121a of the coaxial cable 121 is connected to one inner surface of the metal plate defining the slit hole SHL. One end of the outer conductor 121b of the coaxial cable 121 is connected to the other inner surface of the metal plate that faces the inner surface defining the slit hole SHL. In the example shown in FIG. 2, one end of each of the inner conductor 121a and the outer conductor 121b is connected to a metal plate via a conductive plate 122 attached to the inner surface, as will be described later in detail.

The coaxial cable 121 may be bound by a binding member and connected to the antenna section 11, or may be connected to the antenna section 11 by a crimping piece. Thereby, the connecting portion 12 is firmly connected to the antenna portion 11 .

The length of the metal plate from the surface on the outside S2 side of the structure to the feeding point may be 1/2 or less of the thickness of the metal plate forming the antenna section 11 . Here, the feeding point is a portion of the metal plate forming the antenna portion 11 to which one end of the connection portion 12 is connected. Also, the "thickness" is the length in the direction (z-axis direction) perpendicular to the surface of the metal plate. In the example shown in FIG. 2, the length of the metal plate from the surface on the outside S2 side of the structure to the feeding point is the length z2 from the surface on the outside S2 side of the structure to the feeding point on the iron lid 43. Equivalent to. The thickness of the metal plate forming the antenna section 11 corresponds to the thickness z1 of the iron lid 43 .

The conductive plate 122 is a conductive member. One end of the coaxial cable 121 is attached to the conductive plate 122 , and the conductive plate 122 is fixed to the antenna section 11 . Specifically, the connecting portion 12 includes two conductive plates 122 , one conductive plate 122 to which the inner conductor 121 a of the coaxial cable 121 is attached, and the other conductive plate 122 to which the outer conductor 121 a of the coaxial cable 121 is attached. A conductor 121b is attached. The conductive plate 122 is smaller than the antenna section 11, so the difference in heat capacity between the conductive plate 122 and the coaxial cable is smaller than the difference in heat capacity between the antenna section 11 and the coaxial cable. Therefore, the coaxial cable 121 can be soldered to the conductive plate 122 more stably than when the coaxial cable 121 is directly soldered to the antenna section 11 .

In one example, the conductive plate 122 may be fixed to the antenna section 11 with a conductive adhesive. The conductive adhesive can be, for example, a conductive tape or a conductive adhesive. Also, at this time, the conductive plate 122 may be attached to the antenna section 11 by soldering and then fixed to the antenna section 11 with a conductive adhesive. Alternatively, the conductive plate 122 may be fixed by a crimping piece and attached to the feed point by soldering.

Here, VSWR (Voltage Standing Wave Ratio) in the antenna device 100 described with reference to FIGS. 1 to 3B will be described with reference to FIG.

FIG. 4 shows the VSWR (see solid line) when the slit hole SHL is formed such that the distance to the projection 432 is 0 mm. Also, the VSWR (see broken line) is shown when the slit hole SHL is formed so that the distance to the convex portion 432 is 1 mm. Also, the VSWR (see the dashed line) is shown when the slit hole SHL is formed so that the distance to the convex portion 432 is 5 mm.

When the slit hole SHL is formed such that the distance to the convex portion 432 is 0 mm or 1 mm, the VSWR is greater than 2 in any frequency band. On the other hand, when the slit hole SHL is formed so that the distance to the convex portion 432 is 5 mm, the VSWR is 2 or less in the frequency band of 2.30 GHz or more and less than 2.58 GHz. That is, when the slit hole SHL is formed so that the distance to the projection 432 is 5 mm, impedance matching is achieved in the frequency band of 2.30 GHz or more and less than 2.58 GHz. It was also found that the VSWR was 2 or less in the frequency band when the slit hole SHL was formed such that the distance to the convex portion 432 was greater than 5 mm. Furthermore, it was found that the VSWR was 2 or less in the frequency band even when the slit hole SHL was formed so that the distance to the hole HL was 5 mm or more. In this way, the slit hole SHL is formed so that the distance to the protrusion and the hole HL is 5 mm or more, so that the antenna device 100 can stably radiate radio waves. Communication characteristics can be obtained.

<Manufacturing Method of Antenna Device>
Here, a process for manufacturing the antenna device 100 according to the first embodiment will be described with reference to FIG. FIG. 5 is a flow chart showing an example of a process for manufacturing the antenna device 100 according to the first embodiment. The process of manufacturing the antenna device 100 described with reference to FIG. 5 corresponds to an example of the method of manufacturing the antenna device 100 according to the first embodiment.

In step S1, a slit hole SHL is formed in a metal plate arranged in a structure. Here, the slit holes SHL may be formed by cutting a metal plate in which the slit holes SHL are not formed, or the metal plate may be molded so as to form the slit holes SHL. Further, in this step, the cut portion defining the slit hole SHL in the metal plate may be polished.

One end of the cable is attached to the conductive plate 122 in step S2. As described above, in the example where the cable is coaxial cable 121 , one end of coaxial cable 121 is attached to conductive plate 122 . Specifically, the inner conductor 121 a of the coaxial cable 121 is attached to one conductive plate 122 and the outer conductor 121 b is attached to the other conductive plate 122 .

In step S3, the conductive plate 122 is attached around the slit hole SHL in the metal plate. The periphery of the slit hole SHL may be the side surface of the slit hole SHL. Specifically, one conductive plate 122 is attached to one feeding point in the antenna section 11 , and another conductive plate 122 is attached to another feeding point in the antenna section 11 . At this time, for example, the conductive plate 122 may be attached to the feeding point by soldering.

In step S<b>4 , the conductive plate 122 is fixed to the antenna section 11 . At this time, for example, the conductive plate 122 may be fixed to the antenna section 11 using a conductive adhesive.

By connecting the other end of the coaxial cable 121 to the internal device 200 , the antenna device 100 manufactured in this manner can transmit and receive electrical signals to and from the internal device 200 . Note that the coaxial cable 121 may be connected to the internal device 200 via a connector, another cable, or the like. Also, it is possible to transmit to the external device 300 a radio wave based on an electrical signal received from the internal device 200, or to receive a radio wave from the external device 300 and transmit an electrical signal based on the received radio wave to the internal device 200. .

As described above, the antenna device 100 may not include the conductive plate 122. In such a configuration, one end of the coaxial cable 121 is connected to the antenna section 11 instead of the conductive plate 122 in step S3. may

Moreover, in step S3 described above, the conductive plate 122 is attached to the feeding point of the antenna section 11 by soldering, and in step S4, the conductive plate 122 is fixed with a conductive adhesive, but the present invention is not limited to this. For example, in step S3, the conductive plate 122 may be fixed with a crimping piece, and in step S4, the conductive plate 122 may be attached to the feeding point by soldering.

As described above, the antenna device 100 according to the first embodiment includes the antenna section 11 formed of a metal plate provided with a slit hole SHL and a conductive member. and a connecting portion 12 having one end connected to the periphery of the slit hole SHL in the metal plate. As a result, it is possible to have the toughness equivalent to that of the structure while suppressing the work load.

In addition, in the antenna device 100 according to the first embodiment, the slit hole SHL is formed in the floor slab, which is the portion of the metal plate that does not come into contact with the structure. Thereby, the antenna device 100 can have toughness equivalent to that of the structure.

Further, in the antenna device 100 according to the first embodiment, the other end of the connecting portion 12 is connected to the internal device 200 that transmits and receives electrical signals. As a result, power is directly supplied from the internal device 200 to the antenna section 11, and high radio wave radiation characteristics can be achieved.

Further, in the antenna device 100 according to the first embodiment, the convex portion 432 is formed on the surface of the metal plate, and the slit hole SHL is formed at a position separated from the convex portion 432 by 5 mm or more. Thereby, the antenna device 100 can achieve impedance matching.

In addition, in the antenna device 100 according to the first embodiment, the length from the surface of the metal plate on the outside S2 side of the structure to the feeding point where one end of the connection portion 12 is connected to the metal plate is 1/2 or less of the thickness z1. Thereby, the antenna device 100 can reduce the influence of the metal plate on radio waves transmitted to the external device 300 arranged outside S2 of the structure.

Further, the method for manufacturing the antenna device 100 according to the first embodiment includes steps of forming a slit hole SHL in a metal plate arranged in a structure, attaching one end of the coaxial cable 121 to the conductive plate 122, and attaching the conductive plate 122 around the slit hole SHL in the metal plate. As a result, it is possible to manufacture the antenna device 100 having toughness equivalent to that of the structure while suppressing changes in the outer shape of the metal plate used for the structure and without impairing the strength.

(First modification)
The metal plate forming the antenna section 11 does not have to have a uniform thickness, unlike the metal plate of the above-described embodiment. Here, the thickness is the length in the normal direction of the surface of the metal plate. Here, with reference to FIG. 6A, the thickness in an example in which the metal plate is the plate surface portion 431-1 of the iron lid 43 will be described. A plate surface portion 431-1 shown in FIG. 6A is an example of a metal plate. For example, in the plate surface portion 431-1, the thickness z1 of the second region 431-1B can be set to 9 mm as an example. The thickness z2 of the first region 431-1A may be less than half the thickness z1 of the second region 431-1B. Furthermore, when the thickness z2 is in the range of 0.5 mm or more and 2.0 mm or less, the most stable transmission/reception is possible. The first region 431-1A is a region in which slit holes SHL are formed. The second region 431-1B is a region located adjacent to the first region 431-1A in the short side direction (x-axis direction) of the slit hole SHL. In such a configuration, the connection portion 12 is a conductive member, and one end of the connection portion 12 is connected to the periphery of the slit hole SHL in the metal plate forming the antenna portion 11 . In this example, the periphery of the slit hole SHL is a region (first region 431-1A) that is thinner than the other region (second region 431-1B) of the metal plate and includes the slit hole SHL. Specifically, the conductive plate 122 is attached to the inner S1 side surface of the first region 431-1A, and one end of the coaxial cable 121 is attached to the conductive plate 122. As shown in FIG. At this time, the conductive plate 122 may be attached so that the distance from the surface on the outside S2 side of the antenna section 11 to the feeding point is 1/2 or less of the thickness z1 of the second region 431-1B. . In this modification, in attaching the conductive plate 122 to the periphery of the slit hole SHL in the metal plate in step S3 described above in the process of manufacturing the antenna device 100, the periphery of the slit hole SHL is replaced with another region (second 2 region 431-1B) and includes a slit hole SHL (first region 431-1A).

(Second modification)
The metal plate forming the antenna section 11 does not have to have a uniform thickness, unlike the metal plate of the above-described embodiment. Here, with reference to FIG. 6B, the thickness in an example where the metal plate is the plate surface portion 431-2 of the iron lid 43 will be described. A plate surface portion 431-2 shown in FIG. 6B is an example of a metal plate. For example, in the plate surface portion 431-2, the first region 431-2A has a tapered shape such that the thickness increases with increasing distance from the slit hole SHL. Here, the first area 431-2A is an area in which the slit holes SHL having a thickness of z2 are formed. The thickness z1 of the second region 431-2B is constant and can be 9 mm, for example. Also, the thickness z2 may be less than half the thickness z1. Furthermore, when the thickness z2 is in the range of 0.5 mm or more and 2.0 mm or less, the most stable transmission/reception is possible. Here, the second region 431-2B is a region located adjacent to the first region 431-2A in the short side direction (x-axis direction) of the slit hole SHL. In such a configuration, the connection portion 12 is a conductive member, and one end of the connection portion 12 is positioned from the other region (second region 431-2B) of the metal plate forming the antenna portion 11. It is thin and connected to the region (first region 431-2A) containing the slit hole SHL. Specifically, the conductive plate 122 is attached to the tapered portion of the first region 431 - 2 A, and one end of the coaxial cable 121 is attached to the conductive plate 122 . At this time, the conductive plate 122 may be attached so that the distance from the surface on the outside S2 side of the antenna section 11 to the feeding point is 1/2 or less of the thickness z1 of the second region 431-2B. . Also in this modification, in attaching the conductive plate 122 to the periphery of the slit hole SHL in the metal plate in step S3 described above in the process of manufacturing the antenna device 100, the periphery of the slit hole SHL is a different region (second 2 region 431-1B) and includes a slit hole SHL (first region 431-1A).

<<Second Embodiment>>
A second embodiment of the present invention will be described in detail below with reference to the drawings.

<Configuration of Antenna Device>
An example of the configuration of the antenna device 100-1 according to the second embodiment of the present invention will be described. In 2nd Embodiment, the same code|symbol is attached|subjected about the same structure as 1st Embodiment, and description is abbreviate|omitted.

As shown in FIG. 7, the antenna device 100-1 transmits and receives electrical signals to and from the internal device 200 and wirelessly communicates with the external device 300, similarly to the antenna device 100 of the first embodiment. send and receive electrical signals. In this example, the antenna device 100-1 transmits and receives electric signals to and from the internal device 200 by wireless communication. Also, like the antenna device 100 of the first embodiment, the antenna device 100-1 transmits and receives electrical signals to and from the external device 300 via a wide area network such as LTE or LoRaWAN.

Antenna device 100-1 includes an antenna section (first antenna section) 11, a connection section 12-1, and a second antenna section .

The second antenna section 13 is connected to the other end of the connection section 12-1. The second antenna section 13 is a member having an antenna function, and can be a directional antenna. The second antenna portion 13 can include an internal substrate and a directional conductive pattern provided on the internal substrate. The internal substrate can be rectangular. A directional antenna may be, for example, a patch antenna.

The connection portion 12-1 is a conductive member, and one end of the connection portion 12-1 is connected to the periphery of the slit hole SHL in the metal plate forming the antenna portion 11. FIG. The other end of the connection portion 12-1 is connected to the second antenna portion 13. FIG. Connection 12-1 comprises a cable, which may be coaxial cable 121, for example. The connecting portion 12-1 may further include a conductive plate 122. FIG.

The second antenna section 13 transmits radio waves to the internal device 200 based on the electrical signal received from the antenna section 11 via the connection section 12-1. The second antenna section 13 also receives radio waves transmitted from the internal device 200 and transmits electrical signals based on the radio waves to the antenna section 11 via the connection section 12-1.

<Manufacturing Method of Antenna Device>
Here, a process for manufacturing the antenna device 100-1 according to the second embodiment will be described with reference to FIG. FIG. 8 is a flow chart showing an example of steps for manufacturing the antenna device 100-1 according to the second embodiment. The process of manufacturing the antenna device 100-1 described with reference to FIG. 8 corresponds to an example of the method of manufacturing the antenna device 100-1 according to the second embodiment. In the second embodiment, steps that are the same as those in the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

First, as in the first embodiment, the processing from step S1 to step S4 is executed.

In step S<b>5 , the other end of the coaxial cable 121 is attached to the second antenna section 13 .

As described above, the antenna device 100-1 according to the second embodiment further includes the second antenna section 13, and the other end of the connection section 12-1 is connected to the second antenna section 13. ing. Accordingly, the antenna device 100-1 can transmit and receive electrical signals by wireless communication with the internal device 200, which is a radiation source disposed inside the manhole 400. FIG.

<Other Modifications>
In the present embodiment, the case where the manhole 400 is applied as a structure has been described as an example, but the structure is not limited to the manhole 400, for example, a handhole, a shield tunnel, a sludge storage tank, etc. may be

In this embodiment, an example in which the metal plate is the plate surface portion 431 of the iron lid 43 has been described, but the metal plate is not limited to the plate surface portion 431 of the iron lid 43. For example, a door or the like is formed. It may be a member on the plate surface where the plate is located.

The invention is not limited to the above embodiments and modifications. For example, the various types of processing described above may not only be executed in chronological order according to the description, but may also be executed in parallel or individually according to the processing capacity of the device that executes the processing or as necessary. In addition, appropriate modifications are possible without departing from the gist of the present invention.

Although the above-described embodiments have been described as representative examples, it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of this disclosure. Therefore, the present invention should not be construed as limited by the embodiments described above, and various modifications and changes are possible without departing from the scope of the appended claims.

11 Antenna section (first antenna section)
12, 12-1 connection part 13 second antenna part 41 neck part 42 housing 43 iron cover 100, 100-1 antenna device 121 coaxial cable 121a inner conductor 121b outer conductor 122 conductive plate 200 inner device 300 outer device 400 manhole 431, 431-1, 431-2 Plate surface portions 431-1A, 431-2A First regions 431-1B, 431-2B Second regions 432, 432a, 432b, 432c, 432d Projections

Claims (8)

a first antenna section configured by a metal plate having a slit formed therein and arranged at the entrance of the structure;
a conductive member, one end of which is thinner than the side surface of the slit hole or other area of the metal plate and is connected to an area including the slit hole;
An antenna device comprising: 2. The antenna device according to claim 1, wherein said slit hole is formed in a floor slab portion, which is a portion that does not come into contact with other members when said metal plate is arranged on said structure. 3. The antenna device according to claim 1, wherein the other end of said connecting portion is connected to an internal device for transmitting and receiving electrical signals. 3. The antenna device according to claim 1, further comprising a second antenna section connected to the other end of said connection section. A convex portion is formed on the surface of the metal plate,
5. The antenna device according to any one of claims 1 to 4, wherein said slit hole is formed at a position separated from said convex portion by 5 mm or more. The length of the metal plate from the outer surface of the structure to the feeding point where one end of the connecting portion is connected to the metal plate is 1/2 or less of the thickness of the metal plate. The antenna device according to any one of claims 1 to 5. The connecting part is
a cable;
a conductive plate to which one end of the cable is connected;
The antenna device according to any one of claims 1 to 6, wherein the conductive plate is fixed to the first antenna section with a conductive adhesive. forming a slit hole in a metal plate arranged in a structure;
attaching one end of the cable to the conductive plate;
attaching the conductive plate to a region of the metal plate that includes the slit hole and is thinner than the side surface of the slit hole or other regions;
A method of manufacturing an antenna device, comprising:

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