JP2006229641A - Communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication apparatus for efficiently performing communication between two outer devices. <P>SOLUTION: In the communication apparatus 101, a first conductive layer 111 and a second conductive layer 121 being cloth-shaped, paper-shaped, foil-shaped, film-shaped, plate-shaped, or mesh-shaped good conductors are arranged to keep a certain distance between them. Through holes 112, contact holes 113, and auxiliary holes 114 are arranged at equal interval in the first conductive layer 111. One end of a communication terminal of the outer device is connected to the contact holes 113 and the auxiliary holes 114 so as to be connected to the first conductive layer 111. The other end is penetrated into the through holes 112 and connected to the second conductive layer without being brought into contact with the through holes 112. The outer devices perform communication by electromagnetic waves which are propagated between the first and second conductive layers 111, 121. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication device that performs communication between two external devices by electromagnetic waves propagating between two opposing sheet-like good conductors.

Conventionally, a good conductor in the form of a sheet (cloth, paper, foil, plate, mesh, etc., having a wide surface and a small thickness) (if it is a good conductor in the signal frequency band used for communication) The inventors of the present application have proposed a technology related to a communication device using a good conductor for direct current. For example, in the following documents, a communication device is proposed that transmits a signal by relaying a signal by a plurality of communication elements embedded in a sheet-like member without forming individual wiring.
Japanese Patent Laid-Open No. 2004-007448

  Now, in a communication device that uses two sheet-like good conductors and relays communication by electromagnetic waves propagating between them, it is necessary to consider leakage of electromagnetic waves particularly when connecting to external devices. In addition, it is necessary to consider an incorrect connection of a connector when connecting to an external device.

  The present invention is to meet such a demand, and an object of the present invention is to provide a communication device that efficiently communicates two external devices by electromagnetic waves propagating between two opposing sheet-like good conductors.

  In order to achieve the above object, the following invention is disclosed in accordance with the principle of the present invention.

  A communication apparatus according to a first aspect of the present invention relays communication between a first external device and a second external device, includes a first conductive layer and a second conductive layer, and is configured as follows.

  That is, the first conductive layer is a good conductor in the form of cloth, paper, foil, film, plate, or mesh.

  On the other hand, the second conductive layer is disposed so as to be substantially equidistant from the first conductive layer, and is a good conductor in the form of cloth, paper, foil, film, plate, or mesh.

  Further, the first conductive layer is provided with a plurality of hole pairs of contact holes and through holes, and the distance between the contact holes and the through holes in each hole pair is constant.

  The first external device is connected to the first conductive layer by a conductor in contact with the contact hole of the first hole pair provided in the first conductive layer, and penetrates the first hole pair provided in the first conductive layer. The hole is connected to the second conductive layer by a conductor that penetrates the hole without contacting the first conductive layer.

  On the other hand, the second external device is connected to the first conductive layer by a conductor in contact with the contact hole of the second hole pair provided in the first conductive layer, and penetrates the second hole pair provided in the first conductive layer. The hole is connected to the second conductive layer by a conductor that penetrates the hole without contacting the first conductive layer.

  Further, the first external device and the second external device communicate with each other by electromagnetic waves propagating between the first conductive layer and the second conductive layer.

  In the communication device of the present invention, the plurality of hole pairs can be configured to be periodically arranged in the first conductive layer.

  Moreover, the communication apparatus of this invention can be comprised as follows.

  That is, a dielectric is filled between the first conductive layer and the second conductive layer, and the propagation speed of the electromagnetic wave in the dielectric is slower than the propagation speed of the electromagnetic wave outside the communication device.

  The communication device of the present invention can be configured as follows.

  That is, each of the holes of the plurality of hole pairs has a cylindrical border in the direction toward the second conductive layer, and the length of the cylindrical border is equal to or greater than the radius of the cylinder.

  Moreover, the communication apparatus of this invention can be comprised as follows.

  That is, when the first conductive layer and the second conductive layer are mesh-like good conductors, the size of the mesh is shorter than the wavelength of the electromagnetic wave.

  Moreover, the communication apparatus of this invention can be comprised as follows.

  That is, the first conductive layer is provided with a first auxiliary hole corresponding to the first hole pair and a second auxiliary hole corresponding to the second hole pair.

  On the other hand, the first external device is further connected to the first conductive layer by a conductor in contact with the first auxiliary hole.

  Further, the second external device is further connected to the first conductive layer by a conductor in contact with the second auxiliary hole.

  The through hole of the first hole pair is at the midpoint of the line segment connecting the contact hole of the first hole pair and the first auxiliary hole.

  On the other hand, the through hole of the second hole pair is at the midpoint of the line segment connecting the contact hole of the second hole pair and the second auxiliary hole.

  ADVANTAGE OF THE INVENTION According to this invention, the communication apparatus which performs communication of two external apparatuses efficiently with the electromagnetic waves which propagate between the two opposing sheet-like good conductors can be provided.

  Embodiments of the present invention will be described below. In addition, embodiment described below is for description and does not restrict | limit the scope of the present invention. Therefore, those skilled in the art can employ embodiments in which each of these elements or all of the elements are replaced with equivalent ones, and these embodiments are also included in the scope of the present invention.

  FIG. 1 is a cross-sectional view of a communication apparatus according to the first embodiment of the present invention, and FIG. 2 is an external view of the communication apparatus according to the first embodiment of the present invention. Hereinafter, a description will be given with reference to FIG.

  The communication device 101 includes a first conductive layer 111 and a second conductive layer 121 disposed so as to face the first conductive layer 111 while maintaining a substantially constant distance to or parallel to the first conductive layer 111. The first conductive layer 111 and the second conductive layer 121 are good conductors, and are good conductors in the form of cloth, paper, foil, film, plate, or mesh. Moreover, it is desirable to fill an insulator (not shown) between the first conductive layer 111 and the second conductive layer 121.

  As shown in FIG. 2, the first conductive layer 111 is regularly arranged in units of three holes. FIG. 1 is a cross-sectional view in the linear direction connecting these triplets.

  A through hole 112 is disposed at the center of the three holes, the other two are contact holes 113, and the other is an auxiliary hole 114. A through hole 112 is disposed at the midpoint of the line segment connecting the contact hole 113 and the auxiliary hole 114.

  The contact hole 113 and the auxiliary hole 114 have the same shape and play the same role. Therefore, either one can be omitted.

  FIG. 3 is a cross-sectional view illustrating a state in which a connector of an external device is connected to the communication device. The following description will be given with reference to the above figure and this figure.

  The communication device 101 relays communication between two external communication devices by propagating electromagnetic waves between the first conductive layer 111 and the second conductive layer 121.

  Therefore, any external communication device needs to be connected to both the first conductive layer 111 and the second conductive layer 121.

  Therefore, connection is made with an external communication device as follows.

  That is, the connection with the first conductive layer 111 is performed by the pin 302 coming out from the connector 301 of the external communication device contacting the contact hole 113 and the auxiliary hole 114.

  The connection with the second conductive layer 121 is performed by the pin 303 coming out of the connector 301 of the external communication device passing through the through hole 112 and contacting the second conductive layer 121. Therefore, in order to prevent the pin 303 from short-circuiting with the first conductive layer 111, an insulator 115 is stuck inside the through hole 112.

  Similarly, an insulator 115 for preventing a short circuit with another device is also attached to the surface of the first conductive layer 111.

  In addition, an insulator may be similarly attached to the surface of the second conductive layer 121 (not shown).

  The through hole 112, the contact hole 113, and the auxiliary hole 114 have a cylindrical border in the direction toward the second conductive layer 121.

  The contact hole 113 and the auxiliary hole 114 are further squeezed at their cylindrical ends, and reliable contact is achieved by tightening the pin with this squeezing.

  On the other hand, the pin that has passed through the through-hole 112 has a cylindrical protrusion provided on the second conductive layer 121 as a guide, and the tip of the pin is in direct contact with the second conductive layer 121, or a cylindrical shape that is a conductor. By being fastened to the protrusion, the second conductive layer 121 is connected.

  In many cases, the connection relationship between pins connected to the first conductive layer 111 and the second conductive layer 121 of the communication device 101 cannot be interchanged. Therefore, in such a case, it is necessary to consider prevention of “reverse insertion”. However, if a triple hole is used in this embodiment, the contact hole 113 and the auxiliary hole 114 centering on the through hole 112. Are arranged symmetrically, no problem arises even if they are connected in any direction.

  Therefore, if the distance between the triplets is set to be longer than the distance between the through hole 112 and the contact hole 113, typically, the problem of “reverse insertion” does not occur.

  In addition, the triplet (or the pair of the through hole 112 and the contact hole 113) can be arranged regularly and periodically to maintain symmetry from the viewpoint of minimizing electromagnetic wave leakage from the hole. desirable.

  In the case where the auxiliary hole 114 is omitted, in order to maintain symmetry, it is desirable that the diameters of the contact hole 113 and the through hole 112 be approximately the same, but reverse insertion cannot be prevented. Therefore, in such a case, it is necessary to devise such as allowing reverse insertion as a physical structure or communication protocol adopted by the external communication device or adopting a fitting groove for the connector.

  In addition, if the pin that contacts the second conductive layer 121 through the through hole 112 as a triple is a signal core wire, and the pin that contacts the first conductive layer 111 by the contact hole 113 and the auxiliary hole 114 is a ground wire, Since the signal core wire is sandwiched between the ground wires, it is advantageous in terms of suppressing harmful electromagnetic radiation.

  Now, as the dielectric between the first conductive layer 111 and the second conductive layer 121, the speed of electromagnetic waves propagating through the dielectric is the usage environment (typically in air or in vacuum). Choose something that will be slower.

  In general, since the magnetic permeability μ is often the same as that of vacuum, a material having a large dielectric constant ε may be selected.

  Under such conditions, when the through holes 112, the contact holes 113, and the auxiliary holes 114 are installed at evenly uniform intervals smaller than the wavelength of the electromagnetic wave, they ooze out to the outside of the first conductive layer 111 through these holes. The electromagnetic waves interfered with each other to form an evanescent wave, but the phase changes with a period finer than the electromagnetic wave length in the usage environment, so a traveling wave is not formed in the usage environment, and the intensity of the wave is the first. It attenuates exponentially with respect to the distance from one conductive layer 111. Electromagnetic waves do not leak far away.

  Therefore, it is desirable that the distance between the holes in the row of the through holes 112, the contact holes 113, and the auxiliary holes 114 be shorter than the wavelength of the electromagnetic wave.

  Further, it is desirable to use an electromagnetic wave absorber in order to absorb leakage electromagnetic waves. As the electromagnetic wave absorber, a resistor can be typically used. In the following description, various resistors and termination resistors are used as the electromagnetic wave absorber, but various other electromagnetic wave absorbers can be used.

  An annular resistor 304 is arranged around the connector 301 so as to surround the pins 302 and 303. The resistor 304 can attenuate electromagnetic wave leakage from the gap between the connector 301 and the first communication layer 111.

In the following, we will consider a simple ideal model. If the angular frequency of the electromagnetic wave used for communication is ω and the conductivity of the resistor 304 is σ, the complex dielectric constant is ε + σ / jω. When ε << σ / ω, the attenuation coefficient α of the electromagnetic wave inside the resistor 304 is (μσω / 2) ^1/2 .

  For example, if the 2.4 GHz band is selected as ω and 1 / σ = 1 Ω · cm, α is approximately 103 [1 / m], and the attenuation distance at which the intensity of leakage electromagnetic waves attenuates 1 / e times is approximately 1 mm. . Therefore, the electromagnetic wave entering the resistor 304 is attenuated by about 1 mm.

  What has been described above is an idealized model, and in general, the equivalent resistance in the case of high frequency does not coincide with the direct current resistance. In some cases, an insulator or a good conductor in a direct current exhibits completely opposite properties in a high frequency band. In that sense, the “good conductor” and “insulator” in the above description are determined by the properties in the frequency band used for signal communication, and do not need to be good conductors / insulators in other frequency bands.

  As described above, according to the present embodiment, the risk of short-circuiting when it gets wet is small, the electromagnetic field strength in the vicinity of the hole in the connection portion is small, the electromagnetic wave is difficult to leak, the hole is small, and the wall or tabletop is small. When applied, it is possible to provide a communication device that does not deteriorate the flatness of the surface and is inconspicuous.

  Further, if a multistage structure is provided on a good conductor to which the pin 303 is connected, electromagnetic waves can be attenuated more effectively. FIG. 4 is an explanatory view showing a state of a connector having such a multistage structure.

  As shown in this figure, the good conductors 305 connected to the pins 303 of the connector 301 are provided in a concentric shape (not a “circle”, but may be a square or various polygons), and a resistor 304 is filled therebetween. .

  Since the insulator 115 between the first conductive layer 111 and the resistor 304 is a dielectric, if the impedances of these three elements are set to close values, the electromagnetic waves that have passed through the inner good conductor wall will spread radially. The electromagnetic wave that has entered the resistor 304 and has entered the resistor 304 is absorbed and disappears. Therefore, only a small percentage of the energy of electromagnetic waves that have passed through the inner good conductor wall can reach the outer good conductor wall. Thereafter, by repeating the same process, the rate of leakage to the outside can be made extremely small. In addition, a small percentage of that leaks out.

  By setting such a concentric structure not only in two stages but also in multiple stages, leakage waves can be effectively attenuated over a short distance.

  FIG. 5 is an explanatory diagram for explaining a technique for preventing leakage of electromagnetic waves by a cylindrical border. Hereinafter, a description will be given with reference to FIG.

  In general, no traveling wave can exist inside a conductor cylinder sufficiently smaller than the wavelength of the electromagnetic wave, and even if there is an electromagnetic field near the end of the cylinder, the electromagnetic wave is Attenuating exponentially with respect to the distance of the cylinder, this attenuation distance is about a quarter of the inner diameter (diameter) of the cylinder. Therefore, in order to obtain sufficient attenuation, the length may be longer than about a quarter of the diameter, for example, about the radius.

  Therefore, as shown in the figure, the electromagnetic field in the vicinity of the opening can be strongly attenuated by setting the length of the edge portion to be equal to or larger than the cylindrical inner diameter.

  The shape of the border is not necessarily limited to a cylinder. For example, even in the case of a quadrangular cylindrical border, the same attenuation effect can be obtained, and the attenuation distance at this time is about 0.23 times the side of the quadrangle. In this case as well, if the length of the side of the quadrangle is considered to be the inner diameter (diameter), a sufficient attenuation effect can be obtained if the length is equal to or greater than the radius.

  FIG. 6 is an explanatory diagram showing a method of further covering the outside of the first conductive layer 111 with a flexible conductive cover.

  The conductive cover 601 is short-circuited in contact with the first conductive layer 111. The opening 602 of the conductive cover 601 is provided in accordance with the through hole 112, the contact hole 113, and the auxiliary hole 114, but when the pin 302 or the pin 303 is not inserted, due to its flexibility, Make sure it is closed. This suppresses electromagnetic wave radiation from the hole to which the connector 301 is not connected.

  In this case, an insulating film is provided on the base surface of the pin 303. This prevents the conductive cover 601 and the pin 303 from being short-circuited when the connector 301 is connected.

  FIG. 7 is an explanatory diagram illustrating an example in which the through hole 112, the contact hole 113, and the auxiliary hole 114 are configured so as to be opened only when the pin 302 and the pin 303 are inserted.

  As shown in this figure, when the pin 303 is not inserted, the contact hole 113 and the auxiliary hole 114 are made to close the spring-like opening. Further, when the pin 302 is not inserted, the insulator 115 works in a spring shape so that the opening is closed.

  These techniques can be combined as appropriate and used simultaneously.

(Application examples)
FIG. 8 is an explanatory diagram showing a state in which a wireless device is directly connected to the communication apparatus. Hereinafter, a description will be given with reference to FIG.

  As shown in this figure, by connecting a connection cable 821 for an antenna of an arbitrary wireless device as it is to the first conductive layer 111 and the second conductive layer 121, the first electromagnetic wave can be propagated in the air instead of the first electromagnetic wave. Communication can be performed by propagating electromagnetic waves between the conductive layer 111 and the second conductive layer 121. It can support various wireless devices such as 50Ω coaxial cable output of wireless LAN and Bluetooth.

  In this case, it is necessary to perform impedance conversion. For this purpose, an impedance converter 822 using a microstrip line may be used.

  Further, in the example shown in this figure, a potential difference is provided between the first conductive layer 111 and the second conductive layer 121 by the power source 801, and the electromagnetic wave is attenuated by the resistor 802 at the peripheral portion of the communication device 101. The insulator 803 insulates the first conductive layer 111 and the second conductive layer 121 from each other. Therefore, it is also possible to supply power to the connected wireless device.

  Note that the insulator 803 is not necessary when the resistor 802 functions as an insulator in terms of direct current.

  FIG. 9 is an explanatory diagram showing details of the structure of the peripheral edge. Hereinafter, a description will be given with reference to FIG.

  In this figure, the cross-sectional configuration of the dielectric (insulator) 901 filling the space between the first conductive layer 111 and the second conductive layer 121 and the resistor 802 has a peripheral portion. Indicates.

  In order to prevent reflection of electromagnetic waves at the boundary between the resistor 802 and the dielectric 901, the cross-sectional shape of the resistor 802 is made wedge-shaped.

  In this figure, this cross-sectional shape is considered as a cross-section in the thickness direction of the communication device 101, but the cross-sectional shape in the width direction of the communication device 101 may be wedge-shaped in this way. In other words, the planar structure of the communication device 101 may be a shape when viewed from the direction of the perpendicular to the plane. In many cases, this is easier to create.

  If the wedge spacing is smaller than the wavelength of the electromagnetic wave, this can be regarded as a terminal where the impedance continuously changes. On the other hand, when the wedge interval is larger than the wavelength of the electromagnetic wave, the wave incident from the left is repeatedly reflected between the wedges. In either case, the electromagnetic wave that arrives from the dielectric 901 side is not reflected.

  Note that such a wedge structure is not necessary when the impedance of the electromagnetic wave on the surface of the resistor 802 completely matches the impedance in the dielectric 901. The wedge structure serves to suppress reflection even when this impedance is not perfectly matched.

  By preventing reflection in this way, it is possible to avoid the multipath problem in which signals are received through a plurality of communication paths.

  For example, if the path length reflected by the wall is 3 m longer than the direct distance, the reflected wave arrives with a delay of 10 ns. Therefore, the impulse is received with a spread of about 10 ns, and if 1 bit / (10 ns) = 100 Mbps is exceeded, it is difficult to improve the communication speed.

  On the other hand, if the non-reflection termination process as described above is performed, only the wave of the electromagnetic wave directly transmitted is received, and therefore the transmission speed can be easily increased to the same level as the wave band.

  Hereinafter, other embodiments will be described.

  FIG. 10 is an explanatory diagram for explaining a mode in which pin coupling and capacitive coupling are used in combination. Hereinafter, a description will be given with reference to FIG.

  In the present embodiment, communication electromagnetic waves are transmitted by a signal electrode 951 coupled to the second conductive layer 121 and a ground electrode 952 capacitively coupled to the first conductive layer 111.

  The power supply to the external device is performed through the signal electrode 951 and the power acquisition ground pin 953.

  A power supply capacitor (not shown) on the external device side is connected to the signal electrode 951 through an inductor (not shown) such as a coil, and the power supply capacitor on the external device side and the signal electrode 951 are exchanged. Is disconnected.

  If both signal layers are exposed in the same hole, there is a greater risk of a short circuit. With such a configuration, it is possible to insulate one of the two, and the ground terminal and the signal terminal are coaxial (as shown in this figure). As shown in the figure, by forming a rotationally symmetric configuration surrounding the signal electrode 951, it is possible to avoid generating extra inductance in the signal path.

  Moreover, FIG. 11 is explanatory drawing which shows the form which uses the connector of a coaxial cable as it is. FIG. 12 is an explanatory diagram showing a form using a plug-in type connector. In particular, when clothes, curtains, or the like are used as communication sheets, the connector shown in this figure is considered effective.

  A coaxial cable 972 is connected to the connector 971, and two good conductors 973 and 974 that are insulated via an insulator 976 are connected so as to sandwich the first conductive layer 111 and the second conductive layer 121 of the communication device. In addition, a termination resistor 975 is provided around the insulator 976 as an electromagnetic wave absorber.

  If the coaxial cable has the same impedance as the radiation impedance into the communication layer, communication is possible even if it is directly connected as shown in this figure, but in order to eliminate reflection at the coupling part more completely. A matching circuit is inserted into the coupling part.

  FIG. 13 is an explanatory diagram showing the shape of a communication device corresponding to this connector.

  Holes as shown in this figure are provided in the first conductive layer 111 and the second conductive layer 121 and sandwiched between the connectors 971. The shape of the hole may be circular or a shape like a hole of a button of clothes.

  FIG. 14 is an explanatory diagram illustrating a state in which the communication layer is sandwiched between the connectors.

  When the first conductive layer 111 and the second conductive layer 121 are exposed at the peripheral edge, the peripheral edge of the sheet-like communication device is simply sandwiched between the good conductors 973 and 974 of the connector 971 without providing a hole. Connection can be made.

  As described above, according to the present invention, it is possible to provide a communication device that efficiently communicates two external devices by electromagnetic waves propagating between two opposing sheet-like good conductors, and various communication technologies. Can be applied in the field.

It is sectional drawing of a communication apparatus. It is an external view of a communication apparatus. It is sectional drawing which shows a mode that the connector of an external apparatus is connected to a communication apparatus. It is explanatory drawing which shows the mode of the connector which provided the multistage structure. It is explanatory drawing explaining the method for preventing the leakage of electromagnetic waves by cylindrical edging. It is explanatory drawing which shows the method of further coat | covering the outer side of a 1st conductive layer with a flexible conductive cover. It is explanatory drawing which shows the example which comprised the through-hole, the contact hole, and the auxiliary hole so that it might open only when a pin was inserted. It is explanatory drawing which shows a mode that a radio | wireless apparatus is directly connected to a communication apparatus. It is explanatory drawing which shows the detail of the structure of a peripheral part. It is explanatory drawing explaining the aspect which used pin coupling and capacitive coupling together. It is explanatory drawing explaining the form which uses the connector of a coaxial cable as it is. It is explanatory drawing which shows the form using a connector of the type to insert. It is explanatory drawing which shows the shape of the communication apparatus corresponding to a connector. It is explanatory drawing which shows the state which pinched | interposed the communication layer with the connector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Communication apparatus 111 1st conductive layer 112 Through-hole 113 Contact hole 114 Auxiliary hole 115 Insulator 121 2nd conductive layer 301 Connector 302 Pin 303 Pin 304 Resistor 305 Good conductor 601 Conductive cover 602 Opening 801 Power supply 802 Resistor 803 Insulation Body 821 Connection cable 822 Impedance converter 901 Dielectric 951 Signal electrode 952 Ground electrode 953 Ground pin 971 Connector 972 Coaxial cable 973 Good conductor 974 Good conductor 975 Termination resistance 976 Insulator

Claims (6)

A communication device that relays communication between a first external device and a second external device,
A first conductive layer which is a good conductor in the form of cloth, paper, foil, film, plate or mesh;
A second conductive layer that is a good conductor in the form of a cloth, paper, foil, film, plate, or mesh arranged so as to maintain a substantially equal distance from the first conductive layer;
With
The first conductive layer is provided with a plurality of hole pairs of contact holes and through holes, and the distance between the contact hole and the through hole in each hole pair is constant,
The first external device is connected to the first conductive layer by a conductor in contact with a contact hole of the first hole pair provided in the first conductive layer, and the first external device includes a first hole pair provided in the first conductive layer. Connected to the second conductive layer by a conductor penetrating a through hole without contacting the first conductive layer;
The second external device is connected to the second conductive layer by a conductor in contact with a contact hole of the second hole pair provided in the second conductive layer, and is connected to the second hole pair provided in the second conductive layer. Connected to the second conductive layer by a conductor penetrating a through hole without contacting the first conductive layer;
The first external device and the second external device communicate with each other by electromagnetic waves propagating between the first conductive layer and the second conductive layer. The communication device according to claim 1,
The plurality of hole pairs are periodically arranged in the first conductive layer. The communication device according to claim 2,
A dielectric is filled between the first conductive layer and the second conductive layer,
The propagation speed of electromagnetic waves in the dielectric body is slower than the propagation speed of electromagnetic waves outside the communication device. The communication device according to any one of claims 1 to 3,
Each of the holes of the plurality of hole pairs has a cylindrical border in a direction toward the second conductive layer, and the length of the cylindrical border is equal to or greater than the radius of the cylinder. object. The communication device according to any one of claims 1 to 4, wherein:
When the first conductive layer and the second conductive layer are mesh-like good conductors, the size of the mesh is shorter than the wavelength of the electromagnetic wave. The communication device according to any one of claims 1 to 3,
The first conductive layer is provided with a first auxiliary hole corresponding to the first hole pair and a second auxiliary hole corresponding to the second hole pair,
The first external device is further connected to the first conductive layer by a conductor in contact with the first auxiliary hole,
The second external device is further connected to the first conductive layer by a conductor in contact with the second auxiliary hole,
The through hole of the first hole pair is at the midpoint of a line segment connecting the contact hole of the first hole pair and the first auxiliary hole,
The through hole of the second hole pair is at the midpoint of a line segment connecting the contact hole of the second hole pair and the second auxiliary hole.

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