Antenna device

Abstract

Provided is an antenna device capable of changing the radiation direction of a radiation part by changing the angle of a reflection part with respect to the radiation part.　This antenna device comprises: a first base body provided to face a main surface on the indoor side of window glass; a radiation part provided on the first base body; a second base body provided on the opposite side of the first base body from the window glass; a reflection part provided on the second base body; and an adjustment mechanism capable of adjusting the angle of a main surface of the second base body with respect to the main surface of the first base body.

Description

Antenna device

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

[0002] Conventionally, there has been a base station antenna including at least two reflectors each having at least one radiating element, a radome that forms an internal cavity to house the at least two reflectors, a reflector connecting member that enables the at least two reflectors to rotate, a reflector rotation drive unit that imparts a rotational force to at least one reflector, and a reflector control unit that controls the rotation and stopping of the at least two reflectors (see, for example, Patent Document 1).

[0003] Special Publication No. 2013-514033

[0004] However, in conventional base station antennas (antenna devices), the radiating element (radiating portion) and reflector (reflecting portion) both rotate, so it is not possible to change the radiation direction of the radiating element (radiating portion) by changing the angle of the reflector (reflecting portion) relative to the radiating element (radiating portion).

[0005] Therefore, an object of the present invention is to provide an antenna device that can change the radiation direction of the radiating portion by changing the angle of the reflecting portion with respect to the radiating portion.

[0006] An antenna device according to an embodiment of the present disclosure includes a first base provided opposite the indoor main surface of a window glass, a radiating section provided on the first base, a second base provided on the opposite side of the first base from the window glass, a reflecting section provided on the second base, and an adjustment mechanism capable of adjusting the angle of the main surface of the second base relative to the main surface of the first base.

[0007] By changing the angle of the reflecting portion relative to the radiating portion, an antenna device can be provided that is capable of changing the radiation direction of the radiating portion.

[0008] 1 is a diagram showing an example of a building from the side in which a wireless communication device including an antenna device of an embodiment is installed. FIG. 1 is a diagram showing an example of the configuration of the antenna device of an embodiment. FIG. 2 is a diagram showing an example of the configuration of a reflector of the antenna device of an embodiment. FIG. 3 is a diagram showing an example of the configuration of a spiral antenna of the antenna device of an embodiment. FIG. 4 is a diagram showing an example of the configuration of a spiral antenna of the antenna device of an embodiment. FIG. 5 is a diagram showing an example of a configuration in which two spiral antennas of the antenna device of an embodiment are arranged side by side. FIG. 6 is a diagram showing an example of the circuit configuration of a communication device of a wireless communication device including the antenna device of an embodiment. FIG. 7 is a diagram explaining a change in the radiation direction of radio waves when the angle of the reflector with respect to the spiral antenna is changed from a parallel state. FIG. 8 is a diagram showing an example of a simulation result calculating a change in radiation direction with respect to a change in the angle of the reflector. FIG. 9 is a diagram explaining an example of a use mode of adjusting the angle of the reflector. FIG. 10 is a diagram explaining an example of a use mode of adjusting the angle of the reflector. FIG. 11 is a diagram explaining an example of a use mode of adjusting the angle of the reflector. FIG. 12 is a diagram schematically showing an example of the configuration of an antenna device of a modified embodiment. FIG. 13 is a diagram showing an example of a configuration of a reflector piece of a reflector of an antenna device of a modified embodiment.

[0009] Hereinafter, embodiments to which the antenna device and wireless communication device of the present disclosure are applied will be described. In the following, the same elements will be denoted by the same reference numerals, and duplicated descriptions may be omitted.

[0010] In the following description, the XYZ coordinate system is defined. The direction parallel to the X axis (X direction), the direction parallel to the Y axis (Y direction), and the direction parallel to the Z axis (Z direction) are perpendicular to one another. The XYZ coordinate system is an example of a Cartesian coordinate system. In the following, a planar view refers to a view from the XY plane. In addition, in the following, the length, width, thickness, etc. of each part may be exaggerated to make the configuration easier to understand. Furthermore, terms such as parallel, right angle, orthogonal, horizontal, vertical, up and down, etc., allow for deviations to the extent that they do not impair the effects of the embodiments.

[0011] In the following, a configuration will be described in which the antenna device is disposed facing the indoor main surface of the window glass 11. In this case, the Z direction is the thickness direction connecting the indoor main surface and the outdoor main surface of the window glass 11. The antenna of the antenna device extends along the XY plane. A plan view means a front view of the antenna of the antenna device.

[0012] In the following description, "radio waves" refers to a type of electromagnetic wave, and generally, electromagnetic waves of 3 THz or less are called radio waves. Hereinafter, electromagnetic waves of 3 THz or less emitted from an outdoor base station or relay station will be referred to as "radio waves," and electromagnetic waves in general will be referred to as "electromagnetic waves." In addition, in the following, when referring to "millimeter waves" or "millimeter wave band," this includes not only the frequency band of 30 GHz to 300 GHz, but also the quasi-millimeter wave band of 24 GHz to 30 GHz.

[0013] <Outline of Antenna Device 100 and Wireless Communication Device 200> FIG. 1 is a diagram showing an example of a building 1 in which a wireless communication device 200 including an antenna device 100 according to an embodiment is installed, as viewed from the side.

[0014] The wireless communication device 200 includes an antenna device 100 and a communication device 180. The antenna device 100 includes an antenna, a reflector, and the like, as well as a transmission cable 150. The communication device 180 is connected to the antenna of the antenna device 100 via the transmission cable 150. Details of the antenna device 100 will be described later with reference to FIGS. 2A to 3C.

[0015] Here, a configuration will be described in which the antenna of the antenna device 100 is a spiral antenna, as an example. However, the antenna of the antenna device 100 may be any antenna that radiates radio waves in the -Z direction (outdoors) and also in the +Z direction. This is because the antenna device 100 has a reflector provided on the +Z direction side of the antenna, and the reflector reflects radio waves radiated from the antenna in the +Z direction back in the -Z direction. Therefore, the antenna of the antenna device 100 may be a monopole antenna, a slot antenna, a loop antenna, or a dipole antenna, as examples other than a spiral antenna.

[0016] Also, as an example, a configuration in which the antenna device 100 includes multiple antennas and multiple reflectors will be described. As an example, a configuration in which the number of multiple antennas and the number of multiple reflectors are equal, and one reflector is provided corresponding to each antenna when viewed from the front, will be described. However, the antenna device 100 may also be configured to include one antenna and one reflector.

[0017] 1 shows an outdoor base station BS and a smartphone 50 in addition to a building 1 and a wireless communication device 200. The base station BS is an example of an external device located outside the building 1. Although FIG. 1 shows a base station BS, the external device of the wireless communication device 200 may be a relay station. Even if the external device of the wireless communication device 200 is a relay station, the wireless communication device 200 will communicate with the base station via the relay station.

[0018] Unless otherwise specified, the following description of the operation and configuration of wireless communication device 200 will focus on the operation of receiving radio waves by wireless communication device 200. Because the operation of wireless communication device 200 to transmit radio waves is the opposite of the operation of receiving radio waves, a description of the operation of wireless communication device 200 to transmit radio waves may be omitted.

[0019] The building 1 may be a detached house, a building, an apartment building, or a commercial facility such as a shopping mall or a department store, an airport, a factory, a power facility, a government building, a train station (station building), or a bus stop building. The window 10 is used in these buildings 1. The window 10 includes a windowpane 11 and a window frame (the window frame on the building 1 side). The wireless communication device 200 is installed inside the building 1, for example, and functions as a repeater that relays radio waves arriving from the outside to the inside and relays radio waves from the inside to the outside. Note that, here, a configuration in which the wireless communication device 200 is installed inside the building 1 will be described as an example.

[0020] 1, the XYZ coordinate system is defined, for example, with reference to the indoor main surface of the window glass 11. The window glass 11 may be either single-pane glass or double-glazed glass. The indoor main surface of the window glass 11 that serves as the reference for the XYZ coordinate system is the main surface on the +Z direction side, and the outdoor main surface of the window glass 11 is the main surface on the -Z direction side. The +Z direction side main surface of the window glass 11 and the outdoor side main surface of the window glass 11 are parallel to the XY plane. The building 1 has a wall 1W on the -Z direction side that is parallel to the XY plane, and the window 10 is provided in the wall 1W.

[0021] The radio waves relayed by the wireless communication device 200 including the antenna device 100 are preferably radio waves in the 600 MHz to 30 GHz frequency band, including the Sub-6 frequency band of the fifth generation mobile communication system (5G) and the millimeter wave band. The wireless communication device 200 relays radio waves arriving from an outdoor base station BS or the like indoors. The wireless communication device 200 may also have a function to receive radio waves arriving from a base station BS or the like, convert them into radio waves of a communication standard different from that of the radio waves arriving from the base station BS or the like, and relay them indoors.

[0022] The radio waves relayed by wireless communication device 200 may be Long Term Evolution (LTE), LTE-Advanced (LTE-A), Ultra Mobile Broadband (UMB), or Citizens Broadband Radio Service (CBRS). The radio waves relayed by wireless communication device 200 may be IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra Wideband (UWB), Bluetooth (registered trademark), Low Power Wide Area (LPWA), or the like.

[0023] Here, as an example, a case will be described in which radio waves transmitted and received by the base station BS do not penetrate the wall 1W of the building 1. The reason why radio waves do not penetrate the wall 1W of the building 1 is that the frequency of the radio waves is relatively high. The boundary frequency between the frequency of radio waves that penetrates the wall 1W of the building 1 and the frequency of radio waves that do not penetrate the wall 1W of the building 1 depends on the material and structure of the wall 1W, but as an example, it is about 600 MHz to 3 GHz.

[0024] When radio waves do not penetrate the wall 1W of the building 1, this does not only mean that the radio waves do not penetrate the wall 1W at all, but also means that the radio waves that penetrate the wall 1W are so weak that they do not have sufficient radio wave strength for practical use to communicate using terminals such as a smartphone 50 or a PC (Personal Computer) inside (indoors) the wall 1W of the building 1.

[0025] Radio waves transmitted from the base station BS do not penetrate the wall 1W of the building 1, but penetrate only the window glass 11 of the window 10 to enter the building. Because the radio waves transmitted from the base station BS have high linearity, they only reach the line of sight (LOS) area of ​​the window 10, which makes it easy for blind zones to form inside the building. The window glass 11 of the window 10 is an entrance into the building 1 for radio waves transmitted from the base station BS. Radio waves arriving at the building 1 from the base station BS and passing through the window glass 11 include direct waves that arrive directly from the base station BS to the building 1, and reflected waves that arrive after being reflected by the walls of other buildings or the like along the way. The line of sight area of ​​the window 10 is the area where such direct waves or reflected waves penetrate the window 10 and enter the building 1.

[0026] Here, we will explain a case where radio waves transmitted from the base station BS enter the building 1 by passing only through the window glass 11 without passing through the wall 1W of the building 1. The lower limit of the frequency of such radio waves is, for example, about 600 MHz to 3 GHz.

[0027] The antenna device 100 and the wireless communication device 200 are preferably used when radio waves transmitted from the base station BS enter the building by passing only through the window glass 11 without passing through the wall 1W of the building 1. However, the antenna device 100 and the wireless communication device 200 may also be used when radio waves transmitted from the base station BS pass through the wall 1W of the building 1. This is because even in such a case, the loss of radio waves passing through the window glass 11 is smaller than the loss of radio waves passing through the wall 1W, and radio waves of higher intensity can be received.

[0028] Because the wireless communication device 200 transmits and receives radio waves to and from the base station BS, the antenna device 100 is provided on the indoor main surface of the window glass 11 of the window 10. The transmission cable 150 connects the multiple antennas of the antenna device 100 to the communication device 180. One transmission cable 150 may be connected to each antenna, or one transmission cable 150 may be connected to multiple antennas.

[0029] As an example, the wireless communication device 200 performs amplification processing, or amplification processing and frequency conversion processing, on the radio waves received by the antenna device 100, and outputs the radio waves indoors from an antenna (not shown) or the like provided in the communication device 180. By outputting radio waves indoors from the wireless communication device 200, it becomes possible to easily receive the radio waves at a terminal such as a smartphone 50 or a PC indoors.

[0030] <Configuration of window 10> In the following, an example will be described in which the window 10 is a fixed window, but the window 10 may also be a sliding window that can be opened and closed freely, or a casement window. Furthermore, the window glass 11 held by the window frame may be one or more panes of glass.

[0031] The window glass 11 has a main surface facing the indoor side (+Z direction) and a main surface facing the outdoor side (-Z direction). The window glass 11 may be made of commonly available glass, such as soda-lime glass, alkali-free glass, Pyrex (registered trademark) glass, or quartz glass. The window glass 11 is not limited to a glass plate, and may also be made of a resin surface material such as polycarbonate or acrylic.

[0032] <Specific Configuration of Antenna Device 100> A specific configuration of the antenna device 100 will be described using Fig. 2A and Fig. 2B in addition to Fig. 1. Fig. 2A is a diagram showing an example of the configuration of the antenna device 100. Fig. 2B is a diagram showing an example of the configuration of the reflector 120 of the antenna device 100. Fig. 2A shows a portion corresponding to one spiral antenna 110 out of multiple spiral antennas 110 included in the antenna device 100. Fig. 2A also shows a window glass 11. The window glass 11 has a main surface 11A on the indoor side and a main surface 11B on the outdoor side.

[0033] The antenna device 100 includes a spiral antenna 110, a reflector 120, an adjustment mechanism 130, a matching layer 140, and a transmission cable 150. As an example, the antenna device 100 includes a plurality of spiral antennas 110 and a plurality of reflectors 120. The number of the plurality of spiral antennas 110 is equal to the number of the plurality of reflectors 120, and one reflector 120 is provided corresponding to each spiral antenna 110 in a front view.

[0034] Note that there may be one adjustment mechanism 130 for the plurality of reflectors 120, or the same number of adjustment mechanisms 130 as the plurality of reflectors 120 may be provided, with one adjustment mechanism 130 provided for each reflector 120. Furthermore, the antenna device 100 may include a plurality of adjustment mechanisms 130, and the number of adjustment mechanisms 130 may be less than the number of reflectors 120. For example, one adjustment mechanism 130 may be provided for two reflectors 120. It is sufficient that the adjustment mechanism 130 is capable of independently adjusting the angles of the main surfaces of the plurality of reflectors 120.

[0035] As an example, the antenna device 100 is attached to the indoor main surface 11A of the window glass 11 via a holder (not shown). Such a holder is, for example, made of resin that is transparent to visible light, and is fixed to the main surface 11A of the window glass 11 with double-sided tape or the like, and holds the substrate of the spiral antenna 110 and the adjustment mechanism 130. As an example, the reflector 120 is held by the adjustment mechanism 130.

[0036] Here, as an example, a configuration will be described in which the reflector 120 is not held by a holder that holds the substrate or the like of the spiral antenna 110 and the adjustment mechanism 130, but is held by the adjustment mechanism 130, and the angle of the reflector 120 is adjusted by the adjustment mechanism 130. However, the reflector 120 may be movably held by a holder that holds the substrate or the like of the spiral antenna 110 and the adjustment mechanism 130, and the angle of the reflector 120 may be adjusted by the adjustment mechanism 130.

[0037] "Transparent" to visible light means that the luminous transmittance is at least 40%, preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more. Resin materials that satisfy this condition include acrylic resins such as polymethyl methacrylate, cycloolefin resins, polycarbonate resins, polyethylene terephthalate (PET), and the like. The holder may also be made of transparent glass. A transparent holder can minimize obstruction of the view through the window glass 11.

[0038] <Spiral Antenna 110> The spiral antenna 110 has radiating portions and the like formed on both sides of a substrate. The spiral antenna 110 is, for example, transparent to visible light. A matching layer 140 is provided between the spiral antenna 110 and the main surface 11A of the window glass 11. For example, the spiral antenna 110 is attached to the window glass 11 using a fixing member such as a holder so as to be parallel to the main surface 11A of the window glass 11 and with a gap of approximately 10 mm between the spiral antenna 110 and the main surface 11A. Here, a configuration in which the spiral antenna 110 is disposed parallel to the main surface 11A of the window glass 11 is described; however, the spiral antenna 110 does not have to be parallel to the main surface 11A of the window glass 11. The detailed configuration of the spiral antenna 110 will be described later with reference to Figures 3A to 3C.

[0039] <Reflector 120> The reflector 120 is, for example, provided on the +Z direction side of the spiral antenna 110, and is, for example, held by the adjustment mechanism 130. The reflector 120 has, for example, a rectangular shape in a plan view. The reflector 120 is, for example, transparent to visible light.

[0040] The reflector 120 has a substrate 121 and a reflective conductor 122. The substrate 121 is an example of a second base. The reflective conductor 122 is an example of a reflective portion. The substrate 121 is made of any material that can support the reflective conductor 122.

[0041] As an example, the reflective conductor 122 is provided on the principal surface of the substrate 121 on the -Z direction side. However, the reflective conductor 122 may also be provided on the principal surface of the substrate 121 on the +Z direction side, or may be sandwiched between the substrate 121 and a substrate (not shown) and not exposed. Alternatively, the reflective conductor 122 may be provided on an inner layer of one of multiple substrates. The reflector 120 has a principal surface on the +Z direction side and a principal surface on the -Z direction side. Here, the principal surface of the reflector 120 on the +Z direction side is the same as the principal surface of the substrate 121 on the +Z direction side. The principal surface of the reflector 120 on the -Z direction side is the surface exposed on the -Z direction side of the substrate 121 and the reflective conductor 122. In the following description, the principal surface of the reflector 120 on the -Z direction side is considered to be an example of a principal surface of a reflector. In other words, unless otherwise specified, the principal surface of the reflector 120 refers to the principal surface of the reflector 120 on the -Z direction side.

[0042] When the angle of the reflector 120 is not adjusted by the adjustment mechanism 130, the two main surfaces of the reflector 120 are parallel to the XY plane. The state in which the angle of the reflector 120 is not adjusted by the adjustment mechanism 130 means that the normals to the two main surfaces of the reflector 120 are parallel to the Z direction.

[0043] Furthermore, the substrate 121 may be transparent to visible light. "Transparent" to visible light means that the luminous transmittance is at least 40% or more, preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more.

[0044] As an example, a resin substrate (resin film) may be used as the substrate 121. Examples of resin materials that satisfy the above conditions include acrylic resins such as polymethyl methacrylate, cycloolefin resins, polycarbonate resins, and polyethylene terephthalate (PET). Alternatively, a glass plate may be used as the substrate 121. Examples of glass plates that satisfy the above conditions include soda-lime glass, alkali-free glass, Pyrex (registered trademark) glass, and quartz glass. Here, as an example, a configuration in which the substrate 121 is a resin substrate will be described.

[0045] The reflective conductor 122 may be a conductor such as a thin metal film, but if the substrate 121 is transparent to visible light, it is preferable from the standpoint of visibility that it be formed from a mesh-like thin metal film such as copper, nickel, or gold.

[0046] The reflective conductor 122 is made of zinc oxide (ZnO), tin oxide (SnO ２ The transparent conductive film may be formed of a transparent conductive film such as tin-doped indium oxide (ITO) or indium oxide-tin oxide (IZO), a metal nitride such as titanium nitride (TiN) or chromium nitride (CrN), or a low-e film for low-e (low emissivity) glass.

[0047] As described above, when the substrate 121 is transparent to visible light and the reflective conductor 122 is made of a transparent conductor such as a mesh-like metal thin film, the reflector 120 only needs to have a visual transmittance of 50% or more.

[0048] Although the following describes an example in which the reflector 120 has a substrate 121 and a reflective conductor 122 and is transparent to visible light, the reflector 120 may be, for example, a single metal reflector, since such a reflector can also reflect radio waves radiated from the spiral antenna 110, similar to the reflector 120.

[0049] <Adjustment mechanism 130> As an example, the adjustment mechanism 130 is held together with the substrate of the spiral antenna 110 by a holder that attaches the antenna device 100 to face the indoor main surface 11A of the window glass 11. As an example, the adjustment mechanism 130 is located on the +Z direction side of the reflector 120.

[0050] The adjustment mechanism 130, for example, can independently adjust the angles of the plurality of reflectors 120. The adjustment mechanism 130, for example, can adjust the angles of the reflectors 120 about two axes. Being able to adjust the angles of the reflectors 120 about two axes means, for example, that the angle of the principal surface of the reflector 120 can be changed by rotating it about a rotation axis parallel to the X axis, and that the angle of the principal surface of the reflector 120 can be changed by rotating it about a rotation axis parallel to the Y axis.

[0051] The adjustment mechanism 130 is a mechanism that allows a person installing the antenna device 100 on the window 10 to change the angle of the main surface of the reflector 120 by, for example, applying force to the reflector 120 with their hands or by applying force to the adjustment mechanism 130 with their hands, thereby rotating the reflector 120 around the rotation axis of the adjustment mechanism 130.

[0052] Note that, as an example, the adjustment mechanism 130 may be configured to be able to adjust the angle of the reflector 120 about one axis. That is, as an example, the adjustment mechanism 130 may be configured to be able to change the angle of the main surface of the reflector 120 by either rotating about a rotation axis parallel to the X axis or rotating about a rotation axis parallel to the Y axis.

[0053] The adjustment mechanism 130 is preferably transparent to visible light. The meaning of the adjustment mechanism 130 being transparent to visible light is the same as the meaning of the holder that holds the substrate, etc. of the spiral antenna 110 being transparent to visible light. An example of a resin material that can be used to fabricate the adjustment mechanism 130 that is transparent to visible light is the same as the resin material for the holder of the spiral antenna 110. The adjustment mechanism 130 may also be made of transparent glass. The transparency of the adjustment mechanism 130 can reduce obstruction of the view of the window glass 11.

[0054] <Matching layer 140> The matching layer 140 is provided between the main surface 11A of the window glass 11 and the spiral antenna 110. The matching layer 140 is larger than the spiral antenna 110 in a plan view, and is arranged so as to encompass the outer edge of the spiral antenna 110 in a plan view. A holder that holds the matching layer 140 between the window glass 11 and the spiral antenna 110 may be fixed to the −Z direction side of the substrate of the spiral antenna 110, or may be fixed to the main surface 11A of the window glass 11.

[0055] Radio waves are attenuated when they pass through the window glass 11. In order to suppress radio wave attenuation (loss), a matching layer 140 may be provided. When the spiral antenna 110 transmits and receives radio waves, the matching layer 140 adjusts the electrical length of the radio waves passing through the window glass 11 to match the impedance, thereby reducing loss. Such a matching layer 140 can be made of, for example, polycarbonate, acrylic, COP (cycloolefin polymer), PET (polyethylene terephthalate), polystyrene, glass, or the like.

[0056] There may be one matching layer 140 for the multiple spiral antennas 110, or the same number of matching layers 140 as the multiple spiral antennas 110 may be provided, with one matching layer 140 provided for each spiral antenna 110. Alternatively, the antenna device 100 may include multiple matching layers 140, and the number of matching layers 140 may be less than the number of spiral antennas 110. For example, one matching layer 140 may be provided for two spiral antennas 110.

[0057] <Transmission cable 150> The transmission cable 150 has one end connected to the feed point and ground potential point of the spiral antenna 110, and the other end connected to the communication device 180 in the device main body 101. The transmission cable 150 is, for example, a coaxial cable. One end of the transmission cable 150 is connected to the feed point and ground potential point of the spiral antenna 110 via a coaxial connector 155.

[0058] The transmission cable 150 transmits signals between the spiral antenna 110 and the communication device 180. In Figures 1 and 2A, the transmission cable 150 is connected to the underside of the spiral antenna 110, but it may also be connected to the side or top of the spiral antenna 110.

[0059] 3A, 3B, and 3C are diagrams showing an example of the configuration of the spiral antenna 110. The spiral antenna 110 has a substrate 110A, a first radiating portion 111, a second radiating portion 112, and a feeder line 113. The substrate 110A is an example of a first base. The first radiating portion 111 is an example of a radiating portion.

[0060] In addition, if a monopole antenna, a slot antenna, a loop antenna, or a dipole antenna is used instead of the spiral antenna 110, the antenna device 100 will include the radiating section of the monopole antenna, the slot antenna, the loop antenna, or the dipole antenna instead of the first radiating section 111, the second radiating section 112, and the feeder line 113.

[0061] <Substrate 110A> The substrate 110A is a plate-like member that is rectangular in plan view. The substrate 110A has a main surface 110A1 located on the -Z direction side (the window glass 11 side) and a main surface 110A2 located on the opposite side of the main surface 110A1. The main surfaces 110A1 and 110A2 are parallel to each other. In the following description, the main surface 110A1 is an example of the main surface of the first base and is the main surface of the spiral antenna 110.

[0062] The first radiating portion 111 and the feeder line 113 are provided on the main surface 110A1, and the second radiating portion 112 is provided on the main surface 110A2. Conversely, the second radiating portion 112 may be provided on the main surface 110A1, and the first radiating portion 111 and the feeder line 113 may be provided on the main surface 110A2. Here, a configuration will be described in which the substrate 110A is a plate-like member that is rectangular in plan view. However, the base of the spiral antenna 110 may have any shape as long as it is a member having the main surfaces 110A1 and 110A2, and may be a configuration other than a plate-like member such as a substrate.

[0063] The substrate 110A is formed of any material that is transparent to the radio waves radiated from the base station BS and that can support the first radiating portion 111, the second radiating portion 112, and the feeder line 113. "Transparent to the radiated radio waves" means, for example, that the transmission loss is 10 dB or less. "The substrate 110A is transparent to the radiated radio waves" means that the transmission loss of the substrate 110A is 10 dB or less, preferably 6 dB or less, more preferably 3 dB or less, and even more preferably 1 dB or less.

[0064] The substrate 110A may be transparent to visible light. "Transparent" to visible light means that the luminous transmittance is at least 40% or more, preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more.

[0065] As an example, a resin substrate (resin film) may be used as the substrate 110A. Examples of resin materials that satisfy the above conditions include acrylic resins such as polymethyl methacrylate, cycloolefin resins, polycarbonate resins, and polyethylene terephthalate (PET). Alternatively, a glass plate may be used as the substrate 110A. Examples of glass plates that satisfy the above conditions include soda-lime glass, alkali-free glass, Pyrex (registered trademark) glass, and quartz glass. Here, as an example, a configuration in which the substrate 110A is a resin substrate will be described.

[0066] <First radiating portion 111> The first radiating portion 111 is provided on the main surface 110A1 of the substrate 110A and has a feed point 111A and an open end 111B. The first radiating portion 111 is a radiating portion that extends in a spiral shape between the feed point 111A located toward the center in a plan view and the open end 111B located on the outer side in a plan view. The feed line 113 also has a spiral shape in a plan view, and the first radiating portion 111 extends between the feed line 113 from the feed point 111A toward the open end 111B. Because the antenna device 100 includes multiple spiral antennas 110, one reflector 120 is provided corresponding to each first radiating portion 111 in a front view.

[0067] The first radiating portion 111 is configured with a conductive film formed on the main surface 110A1. The conductive film that configures the first radiating portion 111 will be described later together with the conductive films that configure the second radiating portion 112 and the power supply line 113.

[0068] The portion of the first radiating portion 111 between the feed point 111A and the open end 111B is a logarithmic spiral portion. As an example, the first radiating portion 111 is integrally formed from the feed point 111A to the open end 111B.

[0069] The first radiating portion 111 has two outer edges in plan view, which are an inner edge and an outer edge sandwiching the line width of the spiral pattern of the first radiating portion 111 in plan view.

[0070] The logarithmic spiral portion is a portion of first radiating portion 111 in which two outer edges have a shape based on a logarithmic spiral, and is a portion between feed point 111A and open end 111B. As an example, the spiral shape of first radiating portion 111 having the logarithmic spiral portion is a shape that spirals counterclockwise from feed point 111A on the center side toward open end 111B in a planar view seen from the −Z direction side.

[0071] The logarithmic spiral portion has a shape in which its line width increases from the central feed point 111A toward the open end 111B. The inner and outer edges of the first radiating portion 111 do not have to perfectly match the logarithmic spiral shape in a planar view, and may deviate to some extent. Because the first radiating portion 111 has a line width, the inner and outer edges, particularly near the center, may be interrupted midway through the logarithmic spiral or may deviate from the logarithmic spiral shape. The inner and outer edges of the first radiating portion 111 do not have to perfectly match the logarithmic spiral shape in a planar view due to, for example, adjustments to the shape of the details when forming the first radiating portion 111 using a mesh-like metal thin film, as described below. The phrase "the outer edge of the logarithmic spiral portion has a shape based on a logarithmic spiral in a planar view" means that deviation from such a strict logarithmic spiral is permitted.

[0072] Note that, as an example, a configuration will be described in which the first radiating portion 111 includes a logarithmic spiral portion having a shape based on a logarithmic spiral, but the shape of the outer edge of the spiral portion included in the first radiating portion 111 may be a spiral shape other than a logarithmic spiral. For example, the shape of the outer edge of the spiral portion included in the first radiating portion 111 may have a shape based on a spiral shape such as an Archimedean spiral.

[0073] <Second radiating portion 112> The second radiating portion 112 is provided on the main surface 110A2 of the substrate 110A, and has an open end 112A, a connection portion 112B, and a ground line 112C. The second radiating portion 112 is held at ground potential by connecting the ground line 112C to a shielded line via a coaxial connector 155. The second radiating portion 112 overlaps with the feed line 113 in a plan view, and together with the feed line 113, form a microstrip line. In other words, the second radiating portion 112 serves as the ground line of the microstrip line.

[0074] As an example, the second radiating section 112 has a configuration in which the first radiating section 111 is rotated 180 degrees in a plan view around the center of the spiral of the first radiating section 111 as the center of rotation, and a ground wire 112C is connected to a connection section 112B that is located at a position corresponding to the open end 111B of the first radiating section 111. The shape of the section from the open end 112A to the connection section 112B of the second radiating section 112 corresponds to the shape from the feed point 111A to the open end 111B of the first radiating section 111. For this reason, description of the shapes of the open end 112A and the connection section 112B of the second radiating section 112 will be omitted.

[0075] The second radiating portion 112 has a configuration in which the first radiating portion 111 is rotated 180 degrees in a plan view, so that the feed point 111A becomes an open end 112A, and a ground line 112C is connected to a connection portion 112B corresponding to the open end 111B. The ground line 112C extends to the end of the substrate 110A on the −Y direction side and is connected to the shield wire of the transmission cable 150 by a coaxial connector 155. Note that while FIG. 3C shows an example configuration in which the line width of the ground line 112C is equal to the line width at the connection portion 112B of the second radiating portion 112, the line width of the ground line 112C may be narrower than the line width at the connection portion 112B as long as it is wider than the line width of the feed line 113.

[0076] <Feeder Line 113> The feeder line 113 has a connection portion 113A and an end portion 113B, and has a spiral shape in a plan view. The feeder line 113 has a constant line width from the connection portion 113A to the end portion 113B.

[0077] The connection portion 113A is connected to the feed point 111A of the first radiating portion 111. The end portion 113B is connected to the core wire of the transmission cable 150 via the coaxial connector 155, and thereby receives the signal transmitted from the device main body 101 as input.

[0078] In a plan view, the feed line 113 extends in a spiral shape between the spiral portions from the feed point 111A to the open end 111B of the first radiating portion 111. The gap between the spiral portion of the feed line 113 and the spiral portion of the first radiating portion 111 becomes wider from the connecting portion 113A toward the end portion 113B.

[0079] The spiral portion of the feed line 113 from the connection portion 113A to the end portion 113B overlaps with the second radiation portion 112 in a planar view. The feed line 113 forms a microstrip line together with the second radiation portion 112 at ground potential. The length of the portion of the feed line 113 from the connection portion 113A to the end portion 113B is equal to the length from the open end 112A of the second radiation portion 112 to the end portion of the ground line 112C on the −Y direction side.

[0080] As an example, such a feeder line 113 has a shape based on a logarithmic spiral. The meaning of the feeder line 113 having a shape based on a logarithmic spiral is the same as the meaning of the first radiating section 111 having a shape based on a logarithmic spiral. For example, the logarithmic spiral may be interrupted midway toward the center, and the shape of the feeder line 113 may not completely match the shape of a logarithmic spiral in a planar view due to adjustments to the shape of the details when forming the feeder line 113 from a mesh-like metal thin film, which will be described later. The meaning of the feeder line 113 having a shape based on a logarithmic spiral in a planar view is that deviations from such a strict logarithmic spiral are permitted.

[0081] <Conductive Films of First Radiating Section 111, Second Radiating Section 112, and Power Supply Line 113>

[0082] When the substrate 110A is transparent to visible light, it is preferable from the viewpoint of visibility that the first radiating section 111, the second radiating section 112, and the power supply line 113 are formed from a mesh-like thin metal film such as copper, nickel, or gold.

[0083] The first radiating portion 111, the second radiating portion 112, and the power supply line 113 are made of zinc oxide (ZnO), tin oxide (SnO ２ The transparent conductive film may be formed of a transparent conductive film such as tin-doped indium oxide (ITO) or indium oxide-tin oxide (IZO), a metal nitride such as titanium nitride (TiN) or chromium nitride (CrN), or a low-e film for low-e (low emissivity) glass.

[0084] As described above, when the substrate 110A is transparent to visible light and the first radiating section 111, the second radiating section 112, and the power supply line 113 are made of a transparent conductor such as a mesh-like metal thin film, the spiral antenna 110 only needs to have a visual transmittance of 50% or more.

[0085] <Example of the configuration of multiple spiral antennas 110> Fig. 3D is a diagram showing an example of a configuration in which two spiral antennas 110 are arranged side by side. Of the two spiral antennas 110 shown in Fig. 3D, the right spiral antenna 110 is the same as the spiral antenna 110 shown in Fig. 3B. The left spiral antenna 110 has a configuration that is mirror-symmetrical to the right spiral antenna 110 in a plan view.

[0086] The spiral antenna 110 on the right side of Fig. 3D radiates radio waves polarized clockwise in the -Z direction. The spiral antenna 110 on the left side of Fig. 3D radiates radio waves polarized counterclockwise in the -Z direction. Thus, the two spiral antennas 110 with mirror-symmetrical configurations radiate radio waves with different polarizations. Arranging two spiral antennas 110 with mirror-symmetrical configurations side by side is particularly useful for multiple-input and multiple-output (MIMO) communications.

[0087] <Circuit Configuration of Communication Device 180> Fig. 4 is a diagram showing an example of the circuit configuration of communication device 180. Communication device 180 is provided inside device main body 101 (see Fig. 1). Fig. 4 shows the configuration of a portion of the overall configuration of communication device 180 that corresponds to one spiral antenna 110. Spiral antenna 110 is connected to communication device 180 via transmission cable 150.

[0088] If the distance between the spiral antenna 110 and the communication device 180 is long, the transmission loss of radio waves increases in the transmission cable 150 between the spiral antenna 110 and the communication device 180. Therefore, in order to reduce the transmission loss of radio waves, it is preferable to attach the communication device 180 to the window glass 11 or to a wall 1W or ceiling around the window 10, for example. Furthermore, the communication device 180 may be disposed on the frame of a bay window, for example.

[0089] As an example, the communication device 180 includes an array antenna 180A, a wireless module 181, a switch 182, an LNA (Low Noise Amplifier) ​​183, a mixer 184, an ADC (Analog to Digital Converter) 185, a DAC (Digital to Analog Converter) 186, a mixer 187, and a PA (Power Amplifier) ​​188.

[0090] When there are multiple spiral antennas 110, the switch 182, LNA 183, mixer 184, ADC 185, DAC 186, mixer 187, and PA 188 of the communication device 180 are provided one for each spiral antenna 110. The communication device 180 includes the same number of components from the switch 182 to the PA 188 as the number of spiral antennas 110. As an example, there is only one wireless module 181, which is common to the multiple spiral antennas 110.

[0091] As an example, array antenna 180A is provided inside the housing of communication device 180, or outside communication device 180 and inside device main body 101 (see FIG. 1). Array antenna 180A is an array antenna used when communication device 180 transmits and receives radio waves inside building 1. Array antenna 180A may be provided outside the housing of communication device 180, or may be provided outside device main body 101 (see FIG. 1). Communication device 180 may also be configured to include a single antenna instead of multiple antennas arranged in an array like array antenna 180A.

[0092] The wireless module 181 is configured, for example, by an MCU (Micro Controller Unit), and includes a control unit 181A and a relay unit 181B that performs relay processing. The control unit 181A and the relay unit 181B are functional blocks that represent the functions executed by the MCU.

[0093] When receiving radio waves with spiral antenna 110, control unit 181A switches three-terminal switch 182 to connect spiral antenna 110 to LNA 183. When transmitting radio waves with spiral antenna 110, control unit 181A switches three-terminal switch 182 to connect spiral antenna 110 to PA 188.

[0094] The relay unit 181B includes, as an example, a Wi-Fi (registered trademark) communication unit, is connected to the array antenna 180A, and transmits radio waves based on the digital signal input from the ADC 185 from the array antenna 180A to the inside of the building 1. When the relay unit 181B transmits radio waves to the inside of the building 1 via the array antenna 180A, the radio waves received by the spiral antenna 110 from the base station BS are relayed, and the radio waves are radiated to the inside of the building 1 in which the communication device 180 is located. As a result, the radio waves are radiated over a wide area inside the building 1, making it easier for terminals such as the smartphone 50 located indoors to receive the radio waves. Note that the communication unit that radiates the radio waves relayed indoors by the relay unit 181B is not limited to Wi-Fi, and may be Bluetooth (registered trademark) or the like.

[0095] Furthermore, relay unit 181B performs relay processing on radio waves transmitted from an indoor terminal such as smartphone 50 and received by array antenna 180A, and outputs the result to DAC 186. This allows array antenna 180A to receive radio waves from a wide range inside building 1, making it easier for indoor terminals such as smartphone 50 to transmit radio waves.

[0096] The LNA 183 is provided between the switch 182 and the mixer 184, amplifies the radio waves received by the spiral antenna 110, and outputs the amplified signals while preventing deterioration of the signal-to-noise ratio.

[0097] The mixer 184 demodulates the radio wave output from the LNA 183 by mixing it with a local signal (LO) and outputs an IF (Intermediate Frequency) signal. By converting the signal into an IF signal, digital conversion can be easily performed by the ADC 185.

[0098] The ADC 185 converts the IF signal output from the mixer 184 into a digital signal and outputs the digital signal to the wireless module 181 .

[0099] When the relay unit 181B of the wireless module 181 performs relay processing on the signal received by the array antenna 180A and transmits the signal from the spiral antenna 110, the DAC 186 converts the signal output by the relay unit 181B into an analog signal and outputs the IF signal to the mixer 187.

[0100] The mixer 187 mixes the IF signal with a local signal (LO) to modulate it, and outputs the modulated signal to the PA 188 .

[0101] The PA 188 amplifies the signal output from the mixer 187 and outputs the amplified signal to the transmission cable 150 via the switch 182. As a result, the spiral antenna 110 emits radio waves.

[0102] When the radio waves handled by communication device 180 are Sub-6, communication device 180 may not include mixers 184 and 187. In this case, the signal input to ADC 185 and the signal output from DAC 186 are not IF signals but signals in the Sub-6 frequency band.

[0103] Also, although the communication device 180 has been described here as being configured to convert and amplify frequencies, the communication device 180 may be configured to perform processing such as amplification without converting frequencies.

[0104] The communication device 180 may include an antenna that receives radio waves of a frequency that can penetrate the wall 1W of the building 1. Such an antenna may be provided inside the device main body 101 outside the communication device 180, or may be provided inside the communication device 180. In this case, the relay unit 181B may relay the radio waves received by the spiral antenna 110 and also relay an antenna that receives radio waves of a frequency that can penetrate the wall 1W. The communication device 180 can relay radio waves of a frequency that can penetrate the wall 1W of the building 1 in addition to radio waves of a frequency that cannot penetrate the wall 1W of the building 1, thereby enabling communication over a wider frequency band.

[0105] <Change in Radiation Direction Due to Change in Angle of Reflector 120> Fig. 5A is a diagram illustrating a change in radiation direction 110R1 of radio waves 110R when the angle of the reflector 120 with respect to the spiral antenna 110 is changed from a parallel state. Fig. 5A shows the spiral antenna 110 and the reflector 120 as viewed in the YZ plane. Although the adjustment mechanism 130 is omitted in Fig. 5A, the reflector 120 can be rotated by the adjustment mechanism 130 around a rotation axis 120A that extends parallel to the X direction, for example.

[0106] 5A shows one spiral antenna 110 and one reflector 120, but a plurality of reflectors 120 are provided corresponding to a plurality of spiral antennas 110, and each reflector 120 has a rotation axis 120A. As an example, the rotation axes 120A of the plurality of reflectors 120 are all parallel to each other. This is to enable the plurality of reflectors 120 to rotate in the same direction. Note that the adjustment mechanism 130 may be common to the plurality of reflectors 120, or one adjustment mechanism 130 may be provided for each reflector 120, or the plurality of reflectors 120 may be divided into a plurality of groups, with one adjustment mechanism 130 provided for each group.

[0107] 5A, the position of the reflector 120 when the main surface of the reflector 120 and the main surface of the spiral antenna 110 are parallel is indicated by a dashed line. The main surface of the reflector 120 indicated by the dashed line is parallel to the XY plane. In this state, the radiation direction 110R1 of the radio wave 110R (radio wave 110R indicated by the dashed line) obtained by combining the radio wave radiated from the spiral antenna 110 in the −Z direction and the radio wave radiated in the +Z direction and then reflected by the reflector 120 in the −Z direction is the −Z direction.

[0108] Here, the ellipse representing the radio wave 110R represents an area where radio waves of a predetermined intensity or more are distributed, and the position on the major axis of the ellipse is the position where the radio wave intensity is maximum. The radiation direction 110R1 is the direction in which the radio wave intensity of the radio wave 110R is maximum, and corresponds to the extension direction of the major axis of the radio wave 110R shown by the ellipse.

[0109] When reflector 120 is rotated as shown by arrow A from a state in which the main surface of reflector 120 and the main surface of spiral antenna 110 are parallel to each other, for example, and is tilted to the position shown by the solid line, angle θ of the main surface of reflector 120 with respect to the main surface of spiral antenna 110 changes, and radiation direction 110R1 of radio waves 110R tilts as shown by arrow B. When reflector 120 is rotated in the opposite direction to arrow A, radiation direction 110R1 of radio waves 110R tilts in the opposite direction to arrow B.

[0110] In this state, radio waves 110R are generated by combining radio waves radiated in the -Z direction from spiral antenna 110 with radio waves radiated in the +Z direction from spiral antenna 110 and reflected in the normal direction of the main surface of reflector 120, which is tilted as shown by the solid line. The radiation direction 110R1 of radio waves 110R shown by the solid line is also shown by the solid line.

[0111] That is, by adjusting the angle of the reflector 120 with the adjustment mechanism 130 so that the main surface of the reflector 120 has an angle with respect to the main surface of the spiral antenna 110, the radiation direction 110R1 of the radio wave 110R can be adjusted.

[0112] 5A shows, as an example, a configuration in which the adjustment mechanism 130 is configured to rotate the reflecting plate 120 around a rotation axis 120A extending parallel to the X direction. However, the adjustment mechanism 130 may be configured to rotate the reflecting plate 120 around a rotation axis extending parallel to the Y direction. Alternatively, the adjustment mechanism 130 may be configured to rotate the reflecting plate 120 around the rotation axis 120A extending parallel to the X direction and a rotation axis extending parallel to the Y direction. Furthermore, the rotation axis by which the adjustment mechanism 130 is configured to rotate the reflecting plate 120 does not have to be parallel to the X axis and the Y axis.

[0113] 5B is a diagram showing an example of the results of a simulation that calculates the change in radiation direction 110R1 with respect to the change in angle of reflector 120. Of the directivities of radio waves shown in FIG. 5B , the direction in which the gain is maximum corresponds to radiation direction 110R1. As an example, the radiation direction 110R1 was calculated when reflector 120 was rotated around rotation axis 120A that extends parallel to the X direction with respect to spiral antenna 110.

[0114] The angles shown in Figure 5B indicate angles within the YZ plane, with the 0 degree direction corresponding to the -Z direction, the 90 degree direction corresponding to the +Y direction, the -90 degree direction corresponding to the -Y direction, and the 180 degree direction corresponding to the +Z direction.

[0115] Simulations were performed by adjusting the angle θ (see FIG. 5A ) of the reflector 120 relative to the spiral antenna 110 to 0 degrees, 15 degrees, and 25 degrees. As shown in FIG. 5B , when the angle θ was 0 degrees, the radiation direction 110R1 was approximately 4 degrees. When the angle θ was 15 degrees, the radiation direction 110R1 was approximately 12 degrees, and when the angle θ was 25 degrees, the radiation direction 110R1 was approximately 20 degrees.

[0116] In this way, it was confirmed that when the angle θ of the reflector 120 with respect to the spiral antenna 110 is increased, the absolute value of the angle of the radiation direction 110R1 with respect to the −Z direction increases.

[0117] 5C is a diagram showing an example of the results of a simulation that calculates changes in radiation direction 110R1 with respect to changes in angle θ of reflector 120. In Fig. 5C, the horizontal axis represents angle θ of reflector 120, and the vertical axis represents radiation direction 110R1 in degrees. Radiation direction 110R1 is represented by the absolute value of the angle with respect to the -Z direction.

[0118] Figure 5C shows the results of a simulation similar to that shown in Figure 5B, where the angle θ (see Figure 5A) of the reflector 120 relative to the spiral antenna 110 was adjusted in 5-degree increments within a range from 0 degrees to 25 degrees.

[0119] As shown in FIG. 5C , when the angle θ is 0 degrees, the radiation direction 110R1 is in a direction of 4 degrees, and when the angle θ is 25 degrees, the radiation direction 110R1 is in a direction of approximately 20 degrees. When the angle θ is between 0 degrees and 25 degrees, the angle of the radiation direction 110R1 changes approximately linearly with respect to the angle θ.

[0120] In this way, it was confirmed that when the angle θ of the reflector 120 with respect to the spiral antenna 110 is increased, the absolute value of the angle of the radiation direction 110R1 with respect to the −Z direction increases.

[0121] 6A to 6C are diagrams illustrating an example of a usage mode of adjusting the angle of the reflector 120. Two spiral antennas 110 and two reflectors 120 are shown in each of Figures 6A to 6C.

[0122] 6A, for example, both of the two reflectors 120 are parallel to the spiral antenna 110. In this state, for example, the radiation directions 110R1 of the radio waves 110R of the two spiral antennas 110 are not parallel to the −Z direction but are inclined in opposite directions relative to the −Z direction.

[0123] Here, the spiral antenna 110 may not radiate radio waves directly in front (Z direction) because its actual configuration deviates from a shape based on a theoretical logarithmic spiral. Furthermore, not only the spiral antenna 110 but also monopole antennas, slot antennas, loop antennas, dipole antennas, etc. may not radiate radio waves directly in front (Z direction) due to asymmetry caused by the presence of a feeder line, etc. Furthermore, since this type of radio wave radiation direction not directly in front (Z direction) is particularly likely to occur with spiral antennas and dipole antennas, it is preferable that the antenna included in the antenna device 100 be the spiral antenna 110 or a dipole antenna.

[0124] For example, if the two spiral antennas 110 are configured in mirror symmetry, the radiation directions 110R1 of the two radio waves 110R may be inclined in opposite directions with respect to the −Z direction. More specifically, the radiation direction 110R1 of the left radio wave 110R is inclined to the left with respect to the −Z direction in the YZ plane view seen from the −X direction, and the radiation direction 110R1 of the right radio wave 110R is inclined to the right with respect to the −Z direction in the YZ plane view seen from the −X direction.

[0125] In such a case, as shown in FIG. 6B as an example, by rotating the left reflector 120 clockwise and rotating the right reflector 120 counterclockwise in the YZ plane view seen from the -X direction, the radiation direction 110R1 of the two radio waves 110R can be corrected to be parallel to the -Z direction.

[0126] Furthermore, when the radiation direction 110R1 of one spiral antenna 110 is not directly in front, the radiation direction 110R1 can be easily adjusted to be directly in front by adjusting the angle of the reflector 120. Therefore, when the main surface of the substrate 110A and the main surface of the reflector 120 are parallel to each other, the absolute value of the angle between the radiation direction 110R1 of the first radiating portion 111 of the spiral antenna 110 and the normal direction to the main surface of the substrate 110A may be greater than 0 degrees. This is because, when the radiation direction 110R1 of the radio waves is not directly in front (Z direction), the radiation direction 110R1 can be easily corrected to be directly in front by adjusting the angle of the reflector 120. This makes it easier to use spiral antennas 110 whose radiation direction 110R1 is not directly in front, and simplifies the design of the spiral antenna 110.

[0127] When correcting the radiation direction 110R1 using the reflector 120 in this manner, the correction is easier when the deviation of the radiation direction 110R1 from directly ahead is greater. For this reason, it is preferable that the absolute value of the angle between the radiation direction 110R1 of the first radiating portion 111 of the spiral antenna 110 and the normal direction of the main surface of the substrate 110A when the main surface of the substrate 110A and the main surface of the reflector 120 are parallel to each other is greater than 3 degrees, for example. A spiral antenna 110 in which the deviation of the radiation direction 110R1 from directly ahead is large is easier to design. Furthermore, the overall design of the antenna device 100 is easier if the spiral antenna 110 in which the deviation of the radiation direction 110R1 from directly ahead is large and the reflector 120 is used to correct the radiation direction 110R1, rather than designing a spiral antenna 110 in which the deviation of the radiation direction 110R1 from directly ahead is small.

[0128] 6C , when the right-side reflector 120 is parallel to the spiral antenna 110, the left-side reflector 120 is rotated clockwise in the YZ plane as viewed from the −X direction, so that the radiation directions 110R1 of the two radio waves 110R can be made different. In FIG. 6C , only the left-side reflector 120 is rotated, but by rotating both the left and right reflectors 120 by various rotation amounts, the radiation directions 110R1 of the two radio waves 110R can be made to face in various directions while the radiation directions 110R1 of the two radio waves 110R are different.

[0129] Although the description has been given using two spiral antennas 110 here, the same applies to a case where there are more spiral antennas 110.

[0130] Furthermore, when the antenna device 100 includes three or more spiral antennas 110 and reflectors 120 and the radiation directions 110R1 of at least two of the spiral antennas 110 and reflectors 120 are different, the radiation direction 110R1 may be adjusted by adjusting the angle of the reflector 120 as shown in Figure 6B or 6C. By independently adjusting the angles of the two reflectors 120 corresponding to the two spiral antennas 110, the radiation directions 110R1 can be aligned, or the radiation direction 110R1 can be changed to various different directions. This also has the effect of making the design of the spiral antenna 110 easier.

[0131] Furthermore, when the polarizations of the radio waves radiated from at least two spiral antennas 110 are different, the angle of the reflector 120 may be adjusted to adjust the radiation direction 110R1, as shown in Figure 6B or 6C. Even if the polarizations of the radio waves radiated from the two spiral antennas 110 are different, the radiation directions of the radio waves with different polarizations can be changed independently by independently adjusting the angles of the two reflectors 120 corresponding to the two spiral antennas 110. This also has the effect of making the design of the spiral antenna 110 easier.

[0132] Although a spiral antenna 110 is shown in FIGS. 6A to 6C, the same applies when a monopole antenna, a slot antenna, a loop antenna, a dipole antenna, or the like is used.

[0133] <Modification> Fig. 7A is a diagram schematically illustrating an example of the configuration of an antenna device 100M according to a modification of the embodiment, in which only the spiral antenna 110 and the reflector 120M of the antenna device 100M are shown.

[0134] The antenna device 100M has a configuration in which the reflector 120 of the antenna device 100 of the embodiment (see FIG. 2A) is replaced with a segmented reflector 120M. Here, the configuration of the antenna device 100M will be described using FIG. 7B in addition to FIG. 7A. FIG. 7B is a diagram showing an example of the configuration of reflector pieces 120M1 and 120M2 of the reflector 120M. FIG. 7A shows a state in which the reflector pieces 120M1 and 120M2 are angled with respect to the spiral antenna 110, while FIG. 7B shows a state in which the main surfaces of the reflector pieces 120M1 and 120M2 are parallel to the main surface of the spiral antenna 110.

[0135] The reflector pieces 120M1 and 120M2 have a main surface on the -Z direction side and a main surface on the +Z direction side, and the main surfaces on the ±Z direction sides are parallel to each other. Hereinafter, the main surfaces of the reflector pieces 120M1 and 120M2 are assumed to be the main surfaces on the -Z direction side, similar to the main surface of the reflector 120 of the antenna device 100 of the embodiment (see FIG. 2A).

[0136] Similar to the reflector 120 of the antenna device 100 of the embodiment (see FIGS. 2A and 2B), one reflector 120M is provided for each spiral antenna 110. As an example, the reflector 120M has reflector pieces 120M1 and 120M2. Here, as an example, a configuration in which the reflector 120M is divided into two reflector pieces 120M1 and 120M2 in the Y direction will be described. As an example, the reflector pieces 120M1 and 120M2 have a configuration in which the reflector 120 of the antenna device 100 of the embodiment (see FIGS. 2A and 2B) is divided into two in the Y direction.

[0137] One reflector piece 120M1 and one reflector piece 120M2 are provided for each spiral antenna 110. That is, in the antenna device 100M, two reflector pieces 120M1 and 120M2 are provided for one spiral antenna 110.

[0138] The reflecting plate pieces 120M1 and 120M2 have the same configuration, for example. Each of the reflecting plate pieces 120M1 and 120M2 has a substrate piece 121M and a reflective conductor piece 122M. The substrate piece 121M is an example of a second base piece, and the reflective conductor piece 122M is an example of a reflective piece. One reflective conductor piece 122M is provided on the main surface of each substrate piece 121M on the -Z direction side.

[0139] If the two substrate pieces 121M are regarded as one second base, the second base will have a plurality of substrate pieces 121M (second base pieces). If the two reflective conductor pieces 122M are regarded as one reflective portion, the reflective portion will have a plurality of reflective conductor pieces 122M (reflective portions). One reflective conductor piece 122M (reflective portion) is provided on each of the substrate pieces 121M (second base pieces).

[0140] The substrate piece 121M and the reflective conductor piece 122M have a configuration in which the substrate 121 and the reflective conductor 122 shown in FIG. 2B are divided into two in the Y direction. The substrate piece 121M has a main surface on the -Z direction side and a main surface on the +Z direction side. The main surface on the -Z direction side of the substrate piece 121M and the main surface on the +Z direction side are parallel to each other. In the following description, the main surface on the -Z direction side of the substrate piece 121M will be described as an example of the main surface of the second base piece. In other words, unless otherwise specified, the main surface of the substrate piece 121M refers to the main surface on the -Z direction side of the substrate piece 121M.

[0141] The angles of the principal surfaces of the two substrate pieces 121M provided for each spiral antenna 110 can be independently adjusted by the adjustment mechanism 130. That is, the adjustment mechanism 130 can independently adjust the angles of the principal surfaces of the plurality of substrate pieces 121M relative to the principal surface of the spiral antenna 110.

[0142] In such an antenna device 100M, as shown in Figure 7A as an example, by adjusting the angles of the two reflector pieces 120M1 and 120M2 provided for one spiral antenna 110 so that the main surfaces on the -Z direction side of the reflector pieces 120M1 and 120M2 are closer to each other, the radio waves 110R emitted on the -Z direction side can be made into a thinner beam.

[0143] As an example, by separately adjusting the angles of the two reflector pieces 120M1 and 120M2, when the radiation direction 110R1 of the radio wave 110R is not directly in front of the spiral antenna 110 (-Z direction), as shown in Figure 6A, the radiation direction 110R1 can be adjusted to be directly in front (-Z direction).

[0144] Furthermore, by separately adjusting the angles of the two reflecting plate pieces 120M1 and 120M2, the radiation direction 110R1 of the radio wave 110R can be adjusted to various directions when viewed from the YZ plane.

[0145] 7A and 7B, a configuration in which the reflector 120M is divided into two reflector pieces 120M1 and 120M2 in the Y direction has been described. However, the manner in which the reflector 120M is divided is not limited to this. For example, the reflector 120M may be divided into two reflector pieces in the X direction. In this case, the radiation direction 110R1 of the radio wave 110R can be adjusted to various directions when viewed from the XZ plane.

[0146] The reflector 120M may be divided into four reflector pieces in the X and Y directions. In this case, the radiation direction 110R1 of the radio wave 110R can be adjusted to various directions in the XZ plane and the YZ plane.

[0147] By using such a reflector 120M, it becomes easier to reflect in various directions the radio waves radiated from each spiral antenna 110 toward the reflector pieces 120M1 and 120M2. It also becomes possible to narrow the radio waves 110R into a long, narrow beam.

[0148] While the following description will be given of an example in which the reflector pieces 120M1 and 120M2 of the reflector 120M have a substrate piece 121M and a reflective conductor piece 122M and are transparent to visible light, each of the reflector pieces 120M1 and 120M2 may be, for example, a single metal reflector piece, since such a reflector piece can also reflect radio waves radiated from the spiral antenna 110, just like the reflector pieces 120M1 and 120M2.

[0149] <Effects> The antenna device 100 includes a first base (substrate 110A) provided opposite the indoor main surface of the window glass 11, a radiating section (first radiating section 111) provided on the first base (substrate 110A), a reflector 120 provided on the side of the first base (substrate 110A) opposite the window glass 11, and an adjustment mechanism 130 that can adjust the angle of the main surface of the reflector 120 with respect to the main surface of the first base (substrate 110A). Therefore, it is possible to adjust the angle of the main surface of the reflector 120 with respect to the main surface of the first base (substrate 110A) on which the radiating section (first radiating section 111) is provided.

[0150] Therefore, it is possible to provide an antenna device 100 that can change the radiation direction of the radiation portion by changing the angle of the reflector with respect to the radiation portion.

[0151] The antenna device 100 may also include a plurality of radiating sections (first radiating sections 111) and reflectors 120, and the adjustment mechanism 130 may be capable of independently adjusting the angles of the plurality of reflectors 120. The radiating section (first radiating section 111) is included in the spiral antenna 110. By independently changing the angles of the plurality of reflectors 120 relative to the plurality of spiral antennas 110, it is possible to provide an antenna device 100 that is capable of changing the radiation direction of the plurality of spiral antennas 110. Furthermore, communication using a plurality of channels, such as MIMO communication, becomes possible.

[0152] Furthermore, one reflector 120 may be provided corresponding to each radiating portion (first radiating portion 111) in a front view. The reflector 120 provided corresponding to each spiral antenna 110 including each radiating portion (first radiating portion 111) in a front view can more reliably reflect radio waves radiated from each spiral antenna 110 toward the reflector 120.

[0153] The reflector 120 may also have a second substrate (substrate 121) provided on the opposite side of the first substrate (substrate 110A) from the window glass 11, and a reflective portion (reflective conductor 122) provided on the second substrate (substrate 121). Configuring the reflector 120 with the substrate 121 and the reflective conductor 122 provided on the substrate 121 makes it easy to manufacture the reflector 120 from various materials. With this configuration, a transparent reflector 120 can be realized.

[0154] The second base (substrate 121) may have a plurality of second base pieces (substrate pieces 121M), the reflecting portion (reflective conductor 122) may have a plurality of reflective pieces (reflective conductor pieces 122M), each of the second base pieces (substrate pieces 121M) may be provided with one reflective piece (reflective conductor piece 122M), and the adjustment mechanism 130 may be capable of independently adjusting the angles of the main surfaces of the plurality of second base pieces (substrate pieces 121M) relative to the main surface of the first base (substrate 110A). A plurality of reflector pieces (reflector pieces 120M1 and 120M2) formed of the substrate 110A and the substrate pieces 121M are provided for one spiral antenna 110. By independently adjusting the angles of the reflector pieces 120M1 and 120M2 corresponding to one spiral antenna 110, it becomes easier to reflect the radio waves emitted from one spiral antenna 110 toward the reflector pieces 120M1 and 120M2 in various directions. It also becomes possible to narrow the radio waves 110R into a long, narrow beam.

[0155] Furthermore, the second base (substrate 121) and the reflecting portion (reflective conductor 122) may be transparent, which makes it possible to realize an antenna device 100 that is inconspicuous even when placed over the window glass 11 and does not impair visibility.

[0156] Furthermore, the first base (substrate 110A) and the radiating portion (first radiating portion 111) may be transparent, which makes it possible to realize an antenna device 100 that is inconspicuous even when placed over the window glass 11 and does not impair visibility.

[0157] Furthermore, the radiator (first radiator 111) may be a radiator of a monopole antenna, a slot antenna, a loop antenna, a dipole antenna, or a spiral antenna. When the radio waves from the radiator (first radiator 111) that radiates radio waves in the −Z direction and the +Z direction are reflected by the reflector 120 toward the +Z direction, the reflection direction can be adjusted.

[0158] The antenna device 100 may further include a transmission section (transmission cable 150) having one end connected to the radiation section (first radiation section 111) and the other end connected to a communication device 180 that performs wireless communication via the radiation section (first radiation section 111), and the other end may be detachably connected to the communication device 180. An antenna device 100 that can be easily connected to the communication device 180 can be provided.

[0159] Furthermore, the angle between the radiation direction of the radiating portion (first radiating portion 111) and the normal direction to the principal surface of the first base (substrate 110A) when the principal surface of the first base (substrate 110A) is parallel to the principal surface of the reflector 120 may be greater than 0 degrees. If the radiation direction 110R1 of the radio waves is not directly in front (Z direction), the radiation direction 110R1 can be easily corrected to be directly in front by adjusting the angle of the reflector 120. This makes it easier to use a spiral antenna 110 in which the radiation direction 110R1 of the radiating portion (first radiating portion 111) is not directly in front, and simplifies the design of the spiral antenna 110.

[0160] Furthermore, when the main surface of the first base (substrate 110A) and the main surfaces of the multiple reflectors 120 are parallel, the radiation directions of at least two of the multiple radiators (first radiators 111) may be different. Even if the radiation directions of two spiral antennas 110 each including two radiators (first radiators 111) are different, the radiation directions can be aligned or changed to various different directions by independently adjusting the angles of the two reflectors 120 corresponding to the two spiral antennas 110. This also makes it easier to design the spiral antenna 110.

[0161] Furthermore, the polarizations of the radio waves radiated by at least two of the multiple radiators (first radiators 111) may be different. Even if the polarizations of the radio waves radiated by two spiral antennas 110 each including two radiators (first radiators 111) are different, it is possible to independently change the radiation directions of the radio waves with different polarizations by independently adjusting the angles of the two reflectors 120 corresponding to the two spiral antennas 110. This also makes it easier to design the spiral antenna 110.

[0162] Furthermore, the frequency of the radio waves transmitted and received by the radiator (first radiator 111) may be in the range of 600 MHz to 30 GHz. This makes it possible to provide an antenna device 100 that can efficiently transmit and receive radio waves on the indoor side of the window glass 11 that do not pass through the wall 1W but do pass through the window glass 11.

[0163] Furthermore, the multiple radiators (first radiators 111) may perform Multiple-Input and Multiple-Output (MIMO) communication. Multiple spiral antennas 110 including multiple radiators (first radiators 111) enable communication using multiple channels in MIMO communication.

[0164] While exemplary antenna devices of the present disclosure have been described above, the present disclosure is not limited to the specifically disclosed embodiments, and various modifications and variations are possible without departing from the scope of the claims.

[0165] This international application claims priority based on Japanese Patent Application No. 2023-140360, filed on August 30, 2023, the entire contents of which are incorporated herein by reference.

[0166] DESCRIPTION OF SYMBOLS 1 Building 1W Wall 10 Window 11 Window glass 50 Smartphone 100, 100M Antenna device 110 Spiral antenna 110A Substrate (an example of a first substrate) 110R Radio wave 110R1 Radiation direction 111 First radiation section (an example of a radiation section) 112 Second radiation section 113 Power supply line 120, 120M Reflector 120A Rotation axis 120M1 Reflector piece 120M2 Reflector piece 121 Substrate (an example of a second substrate) 121M Substrate piece (an example of a second substrate piece) 122 Reflector conductor (an example of a reflector) 122M Reflector conductor piece (an example of a reflector piece) 130 Adjustment mechanism 140 Matching layer 150 Transmission cable 180 Communication device 200 Wireless communication device

Claims

1. An antenna device comprising: a first base provided opposite a main surface of a window glass on the indoor side; a radiating section provided on the first base; a reflector provided on the opposite side of the first base to the window glass; and an adjustment mechanism capable of adjusting the angle of the main surface of the reflector relative to the main surface of the first base.

2. The antenna device according to claim 1, comprising a plurality of said radiating sections and said reflectors, and said adjustment mechanism is capable of independently adjusting said angles of said plurality of reflectors.

3. The antenna device according to claim 2, wherein said reflector is provided so as to correspond to each radiating portion when viewed from the front.

4. An antenna device according to any one of claims 1 to 3, wherein the reflector has: a second base provided on the opposite side of the first base from the window glass; and a reflecting portion provided on the second base.

5. An antenna device as described in claim 4, wherein the second base has a plurality of second base pieces, the reflecting portion has a plurality of reflecting pieces, each of the second base pieces is provided with one of the reflecting pieces, and the adjustment mechanism is capable of independently adjusting the angle of the main surfaces of the plurality of second base pieces relative to the main surface of the first base.

6. The antenna device according to claim 4 or 5, wherein the second substrate and the reflecting portion are transparent.

7. The antenna device according to any one of claims 1 to 6, wherein the first base and the radiating portion are transparent.

8. The antenna device according to any one of claims 1 to 7, wherein the radiating portion is a radiating portion of a monopole antenna, a slot antenna, a loop antenna, a dipole antenna, or a spiral antenna.

9. An antenna device as claimed in any one of claims 1 to 8, further comprising a transmission section having one end connected to said radiating section and the other end connected to a communication device which performs wireless communication via said radiating section, said other end being detachably connected to said communication device.

10. An antenna device described in any one of claims 1 to 9, wherein the angle between the radiation direction of the radiating section and the normal direction of the principal surface of the first base when the principal surface of the first base and the principal surface of the reflector are parallel is greater than 0 degrees.

11. The antenna device according to claim 2 or 3, wherein when the main surface of said first base and the main surfaces of said plurality of reflectors are parallel to each other, the radiation directions of at least two of said plurality of radiating sections are different from each other.

12. The antenna device according to claim 2 or 3, wherein the polarizations of the radio waves radiated from at least two of the plurality of radiators are different from each other.

13. An antenna device according to any one of claims 1 to 12, wherein the frequency of radio waves transmitted and received by said radiating portion is in the range of 600 MHz to 30 GHz.

14. The antenna device according to claim 2 or 3, wherein the plurality of radiating sections perform Multiple-Input and Multiple-Output (MIMO) communication.

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