Roof module and antenna set

Abstract

This roof module, which is used as the exterior of the roof of a moving body, comprises: a roof panel (1) that has a metallic recess (11), the opening of said recess facing upward; an antenna (50) that is disposed in the recess; a dielectric member (2) that is composed of a dielectric disposed around the recess; and a conductor member (4) that is disposed on the lower surface of the dielectric member.

Description

Roof module and antenna set Cross-reference to related applications

[0001] This application is based on Japanese Patent Application No. 2024-229331 filed in Japan on December 25, 2024, and the contents of the base application are incorporated herein by reference in their entirety.

[0002] The disclosure in this specification relates to a roof module and an antenna set.

[0003] Patent Document 1 discloses a configuration in which an antenna is housed in a recess provided in the roof of a vehicle. Thus, a technique for improving the aesthetics of the vehicle exterior by embedding the antenna in the roof of the vehicle is known.

[0004] Japanese Patent Application Laid-Open No. 2003-017916

[0005] When an antenna is mounted inside a recess in a metal roof, the radio waves radiated from the antenna interfere with the wall surface of the recess and rise above the vehicle. As a result, there is a problem that the gain in the horizontal direction of the vehicle decreases. [[ID=IP19]]

[0006] One disclosed object is to provide a technique capable of improving the horizontal gain for a vehicle.

[0007] The roof module disclosed herein is a roof module used as an exterior of a roof of a moving body, and includes a roof panel having a metallic recess with an opening facing upward, an antenna disposed in the recess, a dielectric member that is a dielectric disposed around the recess, and a conductor member disposed on the lower surface of the dielectric member.

[0008] The antenna set disclosed herein is an antenna set assembled and used in a hole provided in a roof panel that is an exterior for a roof of a moving body, and includes a circuit module on which an antenna is mounted, a metallic antenna case having an upwardly open shape for closing the hole and accommodating the circuit module, and a dielectric member that is a dielectric plate or a dielectric sheet disposed around the hole.

[0009] It is known that when a dielectric material is applied to the surface of a conductor, surface waves propagate both inside and outside the dielectric. In this technology, a dielectric material with a conductor on its underside is positioned around a recess or hole. As a result, a portion of the radio waves radiated from the opening become surface waves that propagate both inside and outside the dielectric material. These surface waves are then radiated from the dielectric material in the horizontal direction of the vehicle. Therefore, this technology improves the horizontal gain of the moving object.

[0010] This is a diagram showing the mounting position of the roof module. This is a diagram of the roof module. This is a diagram of the roof module. This is a diagram showing the area around the recess. This is a diagram showing the gain when the antenna is activated. This is a diagram showing the gain when the antenna is activated. This is a diagram showing a modified version of the roof module. This is a diagram showing a modified version of the roof module. This is a diagram of the roof module. This is a diagram of the roof module. This is a diagram showing the gain when the antenna is activated. This is a diagram showing a modified version of the roof module the antenna set. This is a diagram showing the gain when the antenna is activated. This is a diagram showing a modified version of the roof module. This is a diagram showing a modified version of the roof module.

[0011] In the following, several forms for carrying out this disclosure will be described with reference to the drawings. This disclosure is not limited to the following embodiments. The configurations disclosed below may be implemented in various ways without departing from the gist of the work. Various modifications may be combined as appropriate, without creating any technical inconsistencies. This disclosure also includes configurations that are not explicitly stated, which are combinations of several modifications.

[0012] (First Embodiment) The roof module 100 will be described with reference to Figures 1, 2, and 3. Note that hatching is omitted in Figure 2. The roof module 100 is a component that provides a roof for a mobile body. The mobile body may be a vehicle, an aircraft such as an electric vertical take-off and landing aircraft or drone, a ship, construction machinery, or agricultural machinery. In this embodiment, the mobile body is a vehicle Hv. The vehicle Hv to which the roof module 100 is applied (hereinafter referred to as the applicable vehicle) may be an electric vehicle such as an HV (Hybrid Vehicle) or a BEV (Battery Electric Vehicle). The applicable vehicle may also be an engine vehicle.

[0013] This disclosure introduces and explains the concept of a right-handed three-dimensional coordinate system having mutually orthogonal X, Y, and Z axes. Specifically, the direction of travel of the vehicle Hv is defined as the forward direction, and the opposite direction of the forward direction is defined as the rear direction. The X-axis is defined along the vehicle width direction. The Y-axis is defined along the longitudinal direction. The vehicle width direction is also the left-right direction of the vehicle Hv. The Z-axis is defined along the vertical direction of the vehicle Hv. The downward direction is also the direction of gravity. The X and Y directions are also the horizontal directions of the vehicle Hv.

[0014] The roof module 100 comprises a roof panel 1, an antenna 50, a dielectric member 2, a conductor member 4, and a resin cover 3. The roof panel 1 is an outer panel that constitutes the roof portion of the vehicle Hv. The roof panel 1 has the function of maintaining the overall strength of the vehicle body. The roof panel 1 is located at the very top of the vehicle Hv and is attached to the vehicle body frame by welding or bonding.

[0015] In this embodiment, the roof panel 1 is made of metal. For example, an aluminum alloy may be used as the material for the roof panel 1, or glass may be used in part. The roof panel 1 may be painted. As an example, the roof panel 1 is formed into a predetermined shape by pressing a metal plate such as a steel plate.

[0016] In this embodiment, the roof panel 1 is a substantially rectangular flat plate. The roof panel 1 has a gently curved shape in the X and Y directions. The roof panel 1 has a substantially flat panel surface 1s. Note that the roof panel 1 may have any shape.

[0017] The roof panel 1 has a metallic recess 11 with an opening facing upward. The recess 11 is the area where the antenna 50 is mounted. In this embodiment, one recess 11 is provided at a position behind the center of the panel. The center of the panel refers to the center of the roof panel 1 in the front-rear direction of the vehicle.

[0018] The recess 11 is formed by a bottom portion 111 and a side wall 112. The side wall 112 is a surface that is continuous with the bottom portion 111 and the panel surface 1s. In this embodiment, the bottom portion 111 and the side wall 112 are substantially planar in shape. The side wall 112 may also be a curved surface that smoothly connects the panel surface 1s and the bottom portion 111. The recess 11 may have a side wall 112 made of metal, and the bottom portion 111 may be made of resin.

[0019] The edge of the opening of the recess 11 is also referred to as the opening edge portion 11e. The opening edge portion 11e may be understood as the opening end of the recess 11, or the peripheral edge of the recess 11. Alternatively, the opening edge portion 11e may be understood as the boundary between the opening of the recess 11 and the panel surface 1s. Specifically, the opening edge portion 11e may be the boundary between the side wall 112 and the panel surface 1s. The recess 11 is provided with a hole for passing wiring or connectors for the circuit module 5, which will be described later, to transmit signals. The opening edge portion 11e is rectangular in shape when viewed from above. Of the opening edge portions 11e, the opening edge portion 11e that is parallel to the X-axis direction and located on the Y-axis side is designated as the first edge portion 113a. Of the opening edge portions 11e, the opening edge portion 11e that is parallel to the X-axis direction and located on the Y-axis side is designated as the second edge portion 113b.

[0020] A circuit module 5 having an antenna 50 is arranged within the recess 11. Note that the circuit module 5 is omitted in Figure 3. The circuit module 5 is a circuit that performs signal processing related to at least one of signal transmission and reception. The circuit module 5 is configured to perform at least one of the following: modulation, demodulation, frequency conversion, amplification, digital-to-analog conversion, and detection. The circuit module 5 is connected to an ECU (Electronic Control Unit) or the like located inside the vehicle via a connector or the like (not shown). The connector may be compatible with an in-vehicle network bus such as a Controller Area Network or Ethernet. The circuit module 5 processes the signal received by the antenna 50 and transmits it to the ECU or the like.

[0021] Antenna 50 is, for example, a dipole antenna. Antenna 50 may also be a monopole antenna, an inverted L antenna, an inverted F antenna, or an array antenna made up of multiple antennas. In this embodiment, there is one antenna 50.

[0022] The circuit module 5 is configured to operate at a predetermined frequency. Hereinafter, the frequency that the circuit module 5 transmits or receives will be referred to as the target frequency. The target frequency may also be referred to as the operating frequency. The circuit module 5 can transmit and receive not only at the target frequency, but also at frequencies within a predetermined range determined based on the target frequency. In this disclosure, the frequency band that the circuit module 5 can transmit or receive will also be referred to as the target frequency band.

[0023] Hereafter, "λ" represents the wavelength of the radio wave at the target frequency (hereinafter also referred to as the target wavelength). For example, "λ / 2" and "0.5λ" mean half the length of the target wavelength, and "λ / 4" and "0.25λ" mean one-quarter the length of the target wavelength. In the examples of component dimensions, expressions using λ may be interpreted as electrical length. Here, electrical length refers to the effective length, taking into account factors such as the fringing electric field and the wavelength shortening effect due to the dielectric. Electrical length is sometimes called effective length.

[0024] In this disclosure, the notation "approximately λ / 2" may be interpreted as a length that falls within λ / 2 ± 20%. The notation "approximately λ / 4" may be interpreted as a length that falls within λ / 4 ± 20%. Unless otherwise specified, such as "exactly," the notation "λ / 2" and "λ / 4" may also be interpreted as "approximately λ / 2" and "approximately λ / 4."

[0025] The circuit module 5 of this embodiment is configured to transmit and receive radio waves in the frequency band used for V2X communication. Here, the target frequency is 5.9 GHz as an example. In other embodiments, the circuit module 5 may be configured to transmit and receive radio waves in the frequency band used for short-range wireless communication, such as the 2.4 GHz band. Of course, the target frequency can be designed appropriately, and other examples include 300 MHz, 760 MHz, 850 MHz, 900 MHz, 1.17 GHz, 1.28 GHz, 1.55 GHz, 2.45 GHz, etc.

[0026] A dielectric member 2 is arranged around the recess 11. The area around the recess 11 is the region of the roof panel 1 from the opening edge 11e to λ. In Figure 4, the region from the opening edge 11e to λ is shown with a dot pattern hatching. In this embodiment, the dielectric member 2 is arranged in front of the recess 11 in the Y direction, adjacent to the recess 11. That is, the distance d1 between the end 2e of the dielectric member 2 and the opening edge 11e in the Y direction is approximately 0 mm.

[0027] The dielectric member 2 is positioned in the direction in which the directivity is to be directed, as viewed from the circuit module 5 (and consequently the antenna 50) located in the recess 11. In other words, in this embodiment, the direction in which the directivity is to be directed can be understood as the Y direction (forward direction).

[0028] In this embodiment, the dielectric member 2 is shaped like a flat plate along the panel surface 1s, as shown in Figures 2 and 3. The dielectric member 2 is rectangular in top view. Although Figure 3 is not a cross-sectional view, for convenience, a dielectric pattern hatching is applied to the dielectric member 2. The shape of the dielectric member 2 may be arbitrarily set. The dielectric member 2 may be circular or annular in top view.

[0029] In the following, the length L of the dielectric member 2 in the Y direction will also be referred to as the first length. Similarly, the length W of the dielectric member 2 in the X direction will also be referred to as the second length. The Y direction is the longitudinal direction of the vehicle, but from another perspective, the Y direction may be understood as the direction toward the dielectric member 2 from the recess 11. Alternatively, the Y direction may be understood as the direction toward the dielectric member 2 from the antenna 50.

[0030] The first length (L) affects the gain of the antenna 50 in the Y direction. Specifically, within a certain range, the longer the first length (L), the more the gain of the antenna 50 in the Y direction tends to improve. In this embodiment, the first length is set to λ / 4. The first length (L) may be set arbitrarily. The first length (L) may be set to λ / 4 or more. The first length (L) may be a value such as 20 mm, 40 mm, or 60 mm. The second length (W) affects the shape of the directivity of the antenna 50 in the horizontal direction. The second length (W) may be set arbitrarily. The second length (W) may be a value such as 500 mm, 700 mm, or 1000 mm.

[0031] The thickness of the dielectric member 2 can be set arbitrarily. In this embodiment, for example, the thickness of the dielectric member 2 is 1.5 mm, but it may be other values ​​such as 1.0 mm or 2.0 mm. The thickness of the dielectric member may be set to a value of 1 / 30 or less of the target wavelength. In this embodiment, the thickness of the dielectric member 2 is substantially uniform, but it does not have to be uniform.

[0032] The material of the dielectric member 2 may be set arbitrarily. In this embodiment, as an example, the material of the dielectric member 2 is PP (Polypropylene). Alternatively, the material of the dielectric member 2 may be FR4 (Flame Retardant 4). A dielectric material with a dielectric constant of about 2 to 5 may be used as the dielectric member 2.

[0033] The dielectric member 2 has a dielectric member surface 2s, which is a surface, and a bottom surface 2b. The dielectric member surface 2s may also be referred to as the top surface. A conductor member 4 is arranged on the bottom surface 2b. The dielectric member 2 is arranged on the panel surface 1s via the conductor member 4.

[0034] The conductor member 4 is made of a conductor such as copper. The conductor member 4 is in the shape of a flat plate that follows the panel surface 1s. The plate shape here also includes thin films such as metal foil. When viewed from above, the conductor member 4 has the same shape (rectangular) as the dielectric member 2. However, the conductor member 4 does not have to have the same shape as the dielectric member 2 when viewed from above, and the shape of the conductor member 4 can be arbitrarily set. The conductor member 4 may be larger than the dielectric member 2. When viewed from above, the conductor member 4 may be circular or annular. The thickness of the conductor member 4 may be sufficiently smaller than the thickness of the dielectric member 2. The end portion 4e of the conductor member 4 is in contact with the first edge portion 113a, as shown in Figure 2. The dielectric member 2 and the conductor member 4 are fixed to the panel surface 1s by methods such as adhesive bonding, engagement, and fastening.

[0035] The resin cover 3 is a dielectric cover that covers the opening of the recess 11 from above. The resin cover 3 has the function of protecting the circuit module 5 from the external environment (wind and rain, etc.). The resin cover 3 is a flat plate shape that conforms to the panel surface 1s. The resin cover 3 may be attached to the roof panel 1 by screws, welding, adhesive, etc.

[0036] The material of the resin cover 3 can be set arbitrarily. In this embodiment, as an example, the material of the dielectric member 2 is PP (Polypropylene). The material of the resin cover 3 may also be FR4 (Flame Retardant 4).

[0037] <Operation of the First Embodiment> Here, the operation of this embodiment will be described. It is known that when a dielectric is coated on the surface of a conductor, surface waves propagate both inside and outside the dielectric. A phase difference occurs between radio waves propagating in a vacuum and radio waves propagating within the dielectric, and surface waves are generated to bridge this discontinuity in phase difference.

[0038] In this configuration, a dielectric member 2, on which a conductive member 4 is located on the lower surface 2b, is positioned around the recess 11. As a result, when the antenna 50 is activated, a portion of the radio waves radiated from the opening of the recess 11 become surface waves that propagate inside and outside the dielectric member 2. These surface waves are then radiated from the dielectric member in the forward direction of the vehicle Hv. Therefore, the roof panel 1 configuration of this disclosure improves the horizontal gain.

[0039] Figures 5 and 6 show the average horizontal gain in the forward direction ±10 degrees when the antenna 50 is activated. Figure 5 shows the simulation results when the first length (L) is changed to λ / 4, λ / 2, λ, 2λ, and 3λ. The value of α in the figure is, for example, 50 mm or 70 mm, and is determined by the material of the dielectric member 2 and the target frequency. The gain when there is no dielectric member 2 was -5.5 dBi. Compared to the case when there is no dielectric member 2, it can be seen that an improvement in forward gain is obtained when the first length is λ / 4 or more.

[0040] Figure 6 shows the simulation results when the second length (W) is changed. The value of β is, for example, 600 mm or 800 mm. Compared to the case without dielectric member 2, it can be seen that an improvement in the gain toward the front of the vehicle is obtained. Furthermore, it can be seen that even when the second length (W) is increased, there is not much change in the gain improvement effect.

[0041] In the above configuration, a conductor member 4 was provided on the lower surface 2b of the dielectric member 2. However, if the roof panel 1 is made of metal, the conductor member 4 can be omitted. As shown in Figure 7, the dielectric member 2 may be placed directly on the roof panel 1 without a conductor member 4. Note that hatching is omitted in Figure 7 and Figures 8 to 10 illustrated below. In this case, the roof panel 1 functions as the conductor member 4. The developers confirmed that, in this modified example as well, the horizontal gain is improved, similar to the above embodiment. With this configuration, since the roof panel 1 plays the role of the conductor member 4, there is no need to prepare a new conductor member 4. Therefore, it is possible to manufacture the roof module 100 with a simple configuration.

[0042] Incidentally, in the above-described configuration, the distance d1 between the end portion 2e of the dielectric member 2 and the first edge portion 113a in the Y direction was set to be approximately 0 mm, but it may be other values. In the modified example of FIG. 8, in the roof panel 1, the dielectric member 2 is disposed at a position separated from the first edge portion 113a by a distance d1 (for example, 0.7 mm). That is, the distance between the end portion 2e and the first edge portion 113a is d1. The distance d1 is set to a value of λ or less. Although the effect is reduced compared to the above-described embodiment, in this configuration as well, the effect of improving the gain in the forward direction can be obtained.

[0043] FIG. 22 shows the simulation results when the distance d1 is changed. The solid line is the analysis result, and the dotted line is the approximation line of the analysis result. From the results of FIG. 22, it can be seen that when the distance d1 is λ, the gain is about the same as when the dielectric member 2 is not provided. Therefore, it can be seen that by setting the distance d1 to λ or less, the effect of improving the gain for the front can be obtained. The horizontal axis of the graph in FIG. 22 represents the interval (that is, the distance d1) between the end portion 2e of the dielectric member 2 and the first edge portion 113a. Also, the long dashed line extending horizontally in the graph represents the gain when the dielectric member 2 is not disposed.

[0044] Further, the recess 11 was provided at a position behind the center in the front-rear direction of the vehicle Hv in the roof panel 1, but it may be provided at any other position. The recess 11 may be provided at a position in front of the panel center. Also, a plurality of recesses 11 may be provided.

[0045] The dielectric member 2 was disposed in the Y direction (that is, the front side) of the recess 11, but it may be provided at any other position. The dielectric member 2 may be disposed in the X direction or the -X direction (that is, the right side or the left side) of the recess 11. In addition, the dielectric member 2 may be disposed in the -Y direction (that is, the rear side) of the recess 11. Also, a plurality of dielectric members 2 may be provided. Further, the dielectric member 2 may be disposed annularly so as to surround the entire circumference of the opening edge portion 113.

[0046] <Second Embodiment>Next, the second embodiment will be described. In the following description of the second embodiment, elements having the same reference numerals as those used previously are the same as the elements with the same reference numerals in the previous embodiments, unless otherwise specified. Also, when only a part of the configuration is described, the previously described embodiments can be applied to other parts of the configuration.

[0047] In the second embodiment, it is different from the first embodiment in that the resin cover 3 functions as the dielectric member 2. That is, the resin cover 3 and the dielectric member 2 may be integrated. As shown in FIG. 9, the resin cover 3 has a base portion 30 and a cover extension portion 31. The base portion 30 is a portion that covers the opening of the recess 11. The cover extension portion 31 extends in the Y direction from the base portion 30 and covers the periphery of the recess 11 in the roof panel 1.

[0048] In this embodiment, the cover extension portion 31 functions as the dielectric member 2 in the above-described embodiment, and the roof panel 1 functions as the conductor member 4. Thereby, as in the above-described embodiment, the gain in the forward direction is improved. Note that, as in the above-described embodiment, the conductor member 4 may be provided on the lower surface of the cover extension portion 31.

[0049] <Third Embodiment>Next, the third embodiment will be described. In the third embodiment, as shown in FIG. 10, a plurality of metal patches 6, which are flat metal conductors, are periodically arranged on the surface 2s of the dielectric member. Such a configuration is called a metasurface. The metal patches 6 may be provided with a coating for protection.

[0050] As shown in FIG. 11, the shape of the metal patch 6 is circular. The shape of the metal patch 6 may be set to any other shape. For example, the metal patch 6 may be annular or rectangular, etc. Note that although FIG. 11 is not a cross-sectional view, for the sake of convenience, the metal patch 6 is hatched with a metal pattern, and the dielectric member 2 is hatched with a dielectric pattern.

[0051] The metal patch 6 is configured to resonate at the target frequency. The resonant frequency is determined by the inductance of the metal patch 6, the capacitance formed between the metal patch 6 and the conductor member 4, and the capacitance formed between the metal patches 6 themselves.

[0052] As shown in Figure 11, in this embodiment, the metal patches 6 are arranged periodically at predetermined intervals in the X and Y directions. In this disclosure, the smallest structural unit that is repeatedly arranged in the periodic structure using the metal patches 6 as shown in Figure 11 is also called a unit cell. A unit cell consists of one metal patch 6 and a gap. The gap is the region in which the dielectric member is exposed, and its size corresponds to half the spacing between the metal patches 6. The size of the gap, in other words, the spacing between the metal patches 6, may be determined by testing or the like to obtain a desired gain.

[0053] The size of the metal patch 6, and therefore the size of the unit cell, is set to be sufficiently smaller than the target wavelength. The smaller the unit cell, the higher the resonant frequency tends to be. Note that multiple unit cells do not necessarily need to be densely packed without gaps; a gap of 1 mm or so may be provided between them. Furthermore, the size of the unit cell is primarily determined by the size of the metal patch 6. Therefore, the description of the unit cell size may be interpreted as the size of the metal patch 6.

[0054] The arrangement of the unit cells can be set arbitrarily. For example, the unit cells may be arranged periodically at predetermined intervals only in the X direction. Similarly, the unit cells may be arranged periodically at predetermined intervals only in the Y direction. The number of metal patches 6 can be set arbitrarily.

[0055] The resonant frequency of the unit cell (and thus the metal patch 6) is adjusted by adjusting the patch size and gap. Patch size is a parameter that indicates the size of the patch, and in this embodiment, it is the diameter of the metal patch 6. An example of the design procedure for the metal patch 6 is described below. First, the patch size is set to λ / 2 or less. Next, the gap spacing d2 is adjusted to design it to resonate at the desired frequency.

[0056] In the following, a group consisting of multiple metal patches 6 will also be referred to as a metal patch group 60. Although Figure 11 is not a cross-sectional view, in order to clearly distinguish between the metal patches 6 and the dielectric members, the metal patches are hatched with a metallic pattern, and the dielectric members are hatched with a dielectric pattern.

[0057] <Operation of the Third Embodiment> Even in a metasurface configuration such as that of the present disclosure, surface waves propagate inside and outside the dielectric member 2. Metasurfaces have the property that the effective dielectric constant increases near the resonant frequency. The amount of power of the surface waves generated inside the dielectric member 2 tends to increase as the effective dielectric constant increases. The amount of power of the surface waves propagating inside and outside the dielectric member 2 may be understood as the degree of concentration of radio waves.

[0058] According to the configuration of this disclosure, the multiple metal patches 6 are configured to resonate at the target frequency. In other words, the metasurface structure of this disclosure increases the effective dielectric constant, and the power of the generated surface waves increases. Consequently, the horizontal gain of the vehicle Hv is improved.

[0059] Figures 12 and 13 show the average horizontal gain in the forward direction ±10 degrees when the antenna 50 is activated. Figure 12 shows the simulation results when the first length (L) is changed to λ / 4, λ / 2, λ, 2λ, and 3λ. Compared to the case without the dielectric member 2 (gain of -5.5 dBi), it can be seen that a gain improvement effect is obtained when the first length is λ / 4 or greater.

[0060] Figure 13 shows the simulation results when the second length (W) is changed. It can be seen that a gain improvement effect is obtained at all second lengths compared to when there is no dielectric member 2. The gain decreases when the second length is around 500 mm. This is thought to be because the radio waves reflected at the end of the dielectric member 2 in the X direction are combined in opposite phase.

[0061] <Modification (1)> As shown in Figure 14, the second and third embodiments may be combined. Note that hatching is omitted in Figures 14 and 15. In this modification, a plurality of metal patches 6 are periodically arranged on the upper surface of the cover extension 31. The cover extension 31 performs the function of the dielectric member 2 in the third embodiment, and the roof panel 1 performs the function of the conductive member 4. As a result, the gain in the forward direction is improved, similar to the third embodiment. Note that the conductive member 4 may be provided on the lower surface of the cover extension 31.

[0062] <Modification (2)> The recess 11 may have a shape in which two recesses of different depths are connected. Hereinafter, the recess 11 will also be referred to as the first recess 11a. In this modification, as shown in Figure 15, the roof panel 1 is provided with a second recess 11b at a position in the Y direction when viewed from the first recess 11a. The first recess 11a and the second recess 11b are continuously connected. The second recess 11b is shallower than the first recess 11a.

[0063] In this modified example, the dielectric member 2 and the metal patch 6 are arranged in the second recess 11b. In this modified example, the roof panel 1 functions as the conductive member 4. The base 30 covers the openings of the first recess 11a and the second recess 11b from above. In this modified example, as in the third embodiment, the gain in the forward direction is improved. In addition, since the dielectric member 2 and the metal patch 6 are arranged in the second recess 11b and the resin cover 3 covers the second recess 11b, the aesthetic appearance is improved.

[0064] As a further modification, the metal patch 6 may be removed from the configuration of this modified example. In this case, the dielectric member 2 and the conductive member 4 operate as in the first embodiment. In this configuration as well, the gain in the forward direction is improved.

[0065] <Modification (3)> As shown in Figure 16, the roof module 100 may be arranged so that metal patches 6 of different sizes are arranged alternately. Although Figure 16 is not a cross-sectional view, for convenience, the metal patches 6 are hatched with a metal pattern and the dielectric member 2 is hatched with a dielectric pattern.

[0066] The smaller metal patch 6 will be referred to as the first metal patch 6a, and the larger metal patch 6 will be referred to as the first metal patch 6b. The first metal patch 6a has a higher resonant frequency than the first metal patch 6b.

[0067] According to this modified example, even when the circuit module 5 operates at two target frequencies, the forward gain can be improved at both target frequencies by corresponding the first metal patch 6a and the first metal patch 6b to each target frequency.

[0068] <Fourth Embodiment> The roof module 100 may include a plurality of antennas 50, a plurality of dielectric members 2, and a plurality of metal patch groups 60. In the modified example shown in Figure 17, three antennas 50 are arranged in the recess 11 at predetermined intervals. The antenna 50 located in the right-hand region inside the recess 11 is referred to as the first antenna 51. The antenna 50 located in the center of the recess 11 in the left-right direction is referred to as the second antenna 52. The antenna 50 located in the left-hand region inside the recess 11 is referred to as the third antenna 53.

[0069] Each antenna 50 is configured to operate at a predetermined frequency. Furthermore, each antenna 50 is configured to operate at a different frequency from the others. For example, the first antenna 51 is configured to operate at 6.0 GHz. The second antenna 52 is configured to operate at 5.0 GHz. The third antenna 53 is configured to operate in the frequency band used for cellular communication. The third antenna 53 is configured to operate at 3.75 GHz.

[0070] In Figure 17, the circuit module 5 is omitted. Each antenna 50 may be mounted on a single common circuit module 5. Each antenna 50 may be mounted on a different circuit module 5. Also, in Figure 17, as in Figure 11, the metal patch 6 is hatched with a metallic pattern, and the dielectric member 2 is hatched with a dielectric pattern.

[0071] In the following, the dielectric member 2 and the group of metal patches 60 arranged on the upper surface of the dielectric member 2 will be referred to as a dielectric unit. The number of dielectric units is the same as the number of antennas 50. In this embodiment, there are three dielectric units. A dielectric unit may include a conductive member 4. In this modified example, the roof panel 1 functions as the conductive member 4.

[0072] For convenience, the three dielectric units will be referred to as the first unit U1, the second unit U2, and the third unit U3. The first unit U1, the second unit U2, and the third unit U3 are arranged at predetermined intervals in the X direction along the first edge 113a of the recess 11. The first unit U1, the second unit U2, and the third unit U3 are arranged to correspond to the three antennas. Specifically, the first unit U1 is positioned on the panel surface 1s in the Y direction (i.e., in front of) the first antenna 51. The second unit U2 is positioned on the panel surface 1s in the Y direction of the second antenna 52. The third unit U3 is positioned on the panel surface 1s in the Y direction of the third antenna 53. In other words, the first unit U1, the second unit U2, and the third unit U3 are arranged in this order in the X direction. The first unit U1 is adjacent to the first antenna 51. The second unit U2 is adjacent to the second antenna 52. The third unit U3 is adjacent to the third antenna 53. The first antenna 51 corresponds to the antenna adjacent to the first unit U1, and the second antenna 52 corresponds to the antenna adjacent to the second unit U2. The third antenna 53 corresponds to the antenna adjacent to the third unit U3.

[0073] The dielectric member 2 included in the first unit U1 is described as the first dielectric member 21. The dielectric member 2 included in the second unit U2 is described as the second dielectric member 22. The dielectric member 2 located in the third unit U3 is described as the third dielectric member 23.

[0074] The group of metal patches 60 included in the first unit U1 will be referred to as the first metal patch group 61. The group of metal patches 60 included in the second unit U2 will be referred to as the second metal patch group 62. The group of metal patches 60 located in the third unit U3 will be referred to as the third metal patch group 63.

[0075] The metal patches 6 constituting the dielectric unit are configured to resonate at the frequency at which the antenna 50 closest to them operates. In other words, the metal patches 6 constituting the first metal patch group 61 are configured to resonate at 6.0 GHz. The metal patches 6 constituting the second metal patch group 62 are configured to resonate at 5.0 GHz. The metal patches 6 constituting the third metal patch group 63 are configured to resonate at 3.75 GHz.

[0076] As mentioned above, the smaller the unit cell, the higher the resonant frequency tends to be. Therefore, in this example, the metal patch 6 constituting the third metal patch group 63 is larger in size than the metal patch 6 constituting the first metal patch group 61 and the metal patch 6 constituting the second metal patch group 62.

[0077] In this configuration, the first unit U1, the second unit U2, and the third unit U3 are arranged around the recess 11 at predetermined intervals from each other. Furthermore, the metal patch 6 constituting each dielectric unit is configured to resonate at the frequency at which the antenna 50 closest to it operates. In other words, each dielectric unit improves the forward gain of the radio waves radiated from the antenna 50 closest to it. As a result, a gain improvement effect in the horizontal direction of the vehicle Hv can be obtained at multiple different frequencies.

[0078] The number of antennas 50 and dielectric units can be set arbitrarily. For example, the number of antennas 50 and dielectric units may be two. The dielectric units were provided in front of the recess 11, but they may also be provided behind the recess 11. For example, one dielectric unit may be provided in front of the recess 11 and the other dielectric unit may be provided behind the recess 11.

[0079] The dielectric member 2 constituting the dielectric unit may be shared with other different dielectric units. For example, a single dielectric member 2 with a sufficiently large area relative to the metal patch group 60 may be used as the dielectric member 2 for the first unit U1 and the second unit U2.

[0080] <Fifth Embodiment> In the fifth embodiment, the roof module 100 is equipped with a solar panel 8 instead of the dielectric member 2. As shown in Figure 18, the solar panel 8 is arranged around the recess 11. The solar panel 8 has glass, a sealing material, and solar cells, etc. Note that hatching is omitted in Figures 18, 19 and 20.

[0081] As shown in Figure 18, the shape of the solar panel 8 is a flat plate that follows the panel surface 1s. The solar panel 8 is rectangular in top view. The shape of the solar panel 8 may be arbitrarily set. The solar panel 8 may be circular or annular in top view. A conductive member 4 is arranged on the lower surface of the solar panel 8. The electricity generated by the solar panel 8 may be supplied to the circuit module 5.

[0082] In this embodiment, the glass of the solar panel 8 performs the same function as the dielectric member 2. As a result, the gain in the Y direction is improved, as in the previously described embodiment. In addition, as in the previously described embodiment, the conductive member 4 is not placed on the lower surface of the solar panel 8, and the solar panel 8 is placed directly on the roof panel 1. In this case, the roof panel 1 functions as the conductive member 4, so the effect of improving the gain in the forward direction is obtained.

[0083] <Modification (4)> In this modification, as shown in Figure 19, the solar panel 8 covers the opening of the recess 11 instead of the resin cover 3. The solar panel 8 has a panel base 80 and a panel extension 81. The panel base 80 is the part that covers the opening of the recess 11. The panel extension 81 extends from the panel base 80 in the Y direction and covers the periphery of the recess 11 in the roof panel 1.

[0084] In this modified example, the extended panel portion 81 performs the function of the dielectric member 2 in the previously described embodiment, and the roof panel 1 performs the function of the conductive member 4. As a result, the gain in the forward direction is improved, similar to the previously described embodiment. In addition, as in the previously described embodiment, the conductive member 4 may be provided on the lower surface of the extended panel portion 81.

[0085] <Modification (5)> In this modification, as shown in Figure 20, a second recess 11b is provided in front of the first recess 11a in the Y direction. In this modification, the dielectric member 2 and the metal patch 6 are arranged in the second recess 11b. In this modification, the roof panel 1 functions as the conductive member 4. The solar panel 8 covers the openings of the first recess 11a and the second recess 11b from above. In this modification as well, the gain in the forward direction is improved, similar to the embodiment described above. In addition, the aesthetics are improved because the dielectric member 2 and the metal patch 6 are arranged in the second recess 11b and the solar panel 8 covers the second recess 11b.

[0086] <Other Embodiments> In the embodiments described above, the antenna 50 is shown to be placed in a recess 11 of the roof panel 1, but the configuration is not necessarily limited to this. For example, the antenna set 200 may be assembled into a hole 13 provided in the roof panel 1. The hole 13 is a rectangular through-hole when viewed from above. Figure 21 shows the state in which the antenna set 200 is assembled into the hole 13. Note that hatching is omitted in Figure 21.

[0087] The antenna set 200 comprises a circuit module 5, an antenna case 210, a dielectric member 2 which is a dielectric plate or dielectric sheet, and a resin cover 3. The antenna case 210 is a metal housing with an open top that closes the hole 13 and houses the circuit module 5. The antenna case 210 may be attached to the roof panel 1 by screws, welding, adhesive, etc. The antenna case 210 is provided with holes for passing wiring or connectors for the circuit module 5 to transmit signals.

[0088] The antenna case 210 is formed by a housing bottom 211 and a housing side wall 212. In this embodiment, the housing bottom 211 and the housing side wall 212 are substantially planar in shape. The housing side wall 212 may have a curved shape that smoothly connects the panel surface 1s and the housing bottom 211. The edge of the hole 13 in the roof panel 1 is also referred to as the hole edge 13e. The hole edge 13e is rectangular in shape when viewed from above. Of the hole edge 13e, the hole edge 13e that is parallel to the X-axis direction and located on the Y-axis side is designated as the first hole edge 213a. Of the hole edge 13e, the hole edge 13e that is parallel to the X-axis direction and located on the Y-axis side is designated as the second hole edge 213b.

[0089] The resin cover 3 is a dielectric cover that covers the opening of the antenna case 210 from above. The resin cover 3 has the function of protecting the circuit module 5 from the external environment (wind and rain, etc.). The resin cover 3 may be attached to the antenna case 210 by screws, welding, adhesive, etc.

[0090] The dielectric member 2 is positioned around the hole 13. The area around the hole 13 is the region of the roof panel 1 that is λ / 4 or less from the hole edge 13e. In this embodiment, the dielectric member 2 is positioned adjacent to the first hole edge 213a in the Y direction (i.e., the front side) of the hole 13.

[0091] In this embodiment as well, an improvement in gain in the forward direction can be obtained. In another embodiment, the hole 13 may be the opening of a recess 11 provided in the roof panel 1.

[0092] A conductive member 4 may be provided on the lower surface of the dielectric member 2, similar to the embodiments described above. For example, if the roof panel 1 is made of a dielectric material, the roof panel 1 does not function as a conductive member 4. In such cases, by providing a conductive member 4 on the lower surface of the dielectric member 2, surface waves are generated in the dielectric member 2, and a gain improvement effect in the forward direction can be obtained.

[0093] As shown in Figure 23, the dielectric member 2 may be housed in the second recess 11b. The second recess 11b is shallower than the first recess 11a and is set to a depth approximately the same as the thickness of the dielectric member 2. Therefore, the panel surface 1s and the dielectric member surface 2s are at the same height in the Z direction. In other words, the depth of the second recess 11b may be designed so that the panel surface 1s and the dielectric member surface 2s are connected continuously (smoothly). Note that hatching is omitted in Figures 23 and 24.

[0094] As shown in Figure 24, the cover extension portion 31 may be housed in the second recess 11b. The second recess 11b is shallower than the first recess 11a and is set to a depth approximately the same as the thickness of the cover extension portion 31. Therefore, the panel surface 1s and the cover surface 31s, which is the surface of the cover extension portion 31, are at the same height in the Z direction.

[0095] (Disclosure of Technical Ideas) This specification discloses several technical ideas as described in the following paragraphs. Some paragraphs may be written in a multiple dependent form, where subsequent paragraphs optionally refer to preceding paragraphs. Furthermore, some paragraphs may be written in a multiple dependent form, where they refer to other multiple dependent forms. These paragraphs written in multiple dependent forms define several technical ideas.

[0096] (Technical Concept 1) A roof module used as the exterior of the roof of a mobile vehicle, comprising: a roof panel (1) having a metallic recess (11) with an opening facing upward; an antenna (50) disposed within the recess; a dielectric member (2) which is a dielectric material disposed around the recess; and a conductor member (4) disposed on the lower surface of the dielectric member.

[0097] (Technical Concept 2) The roof module according to Technical Concept 1, wherein the antenna is configured to operate at a predetermined frequency, and the distance between the dielectric member and the edge (11e) of the opening is one wavelength or less of the frequency.

[0098] (Technical Idea 3) The roof module according to technical idea 1 or 2, wherein the roof panel is made of metal, and the conductive member is the roof panel.

[0099] (Technical Idea 4) A roof module according to any one of Technical Ideas 1 to 3, comprising a dielectric resin cover (3) that covers the opening from above, the resin cover having a cover extension portion (31) that covers the area around the recess of the roof panel, and the dielectric member being the cover extension portion.

[0100] (Technical Concept 5) The roof module according to Technical Concept 1, wherein the antenna is configured to operate at a predetermined frequency, the dielectric member has a flat plate shape that conforms to the surface of the roof panel, and the horizontal length of the dielectric member is 1 / 4 or more of the wavelength of the frequency.

[0101] (Technical Concept 6) The roof module according to Technical Concept 1, comprising a plurality of metal patches (6) which are flat metal conductors periodically arranged on the upper surface of the dielectric member, wherein the antenna is configured to operate at a predetermined frequency, and the plurality of metal patches are configured to resonate at the predetermined frequency.

[0102] (Technical Concept 7) The roof module according to Technical Concept 6, comprising a plurality of antennas each operating at a different frequency, wherein the plurality of antennas are arranged within the recess at a predetermined distance from each other, a plurality of dielectric units including the dielectric member and the conductive member are arranged around the recess, the plurality of dielectric units are arranged alongside the plurality of antennas, the dielectric unit includes a plurality of metal patches periodically arranged on the upper surface of the dielectric member, and the plurality of metal patches included in the dielectric unit are configured to resonate at the frequency in which the antenna adjacent to the dielectric unit operates.

[0103] (Technical Concept 8) An antenna set for use by being assembled into a hole (13) provided in a roof panel which is the exterior roof of a mobile body, comprising: a circuit module (5) on which an antenna is mounted; a metal antenna case (210) having an open top shape for closing the hole and housing the circuit module; and a dielectric member (2) which is a dielectric plate or dielectric sheet arranged around the hole.

Claims

1. A roof module used as the exterior of the roof of a mobile vehicle, comprising: a roof panel (1) having a metallic recess (11) with an opening facing upward; an antenna (50) disposed within the recess; a dielectric member (2) which is a dielectric material disposed around the recess; and a conductor member (4) disposed on the lower surface of the dielectric member.

2. The roof module according to claim 1, wherein the antenna is configured to operate at a predetermined frequency, and the distance between the dielectric member and the edge (11e) of the opening is one wavelength or less of the frequency.

3. The roof module according to claim 1 or 2, wherein the roof panel is made of metal, and the conductor member is the roof panel.

4. The roof module according to claim 1 or 2, comprising a dielectric resin cover (3) that covers the opening from above, wherein the resin cover has a cover extension portion (31) that covers the area around the recess of the roof panel, and the dielectric member is the cover extension portion.

5. The roof module according to claim 1, wherein the antenna is configured to operate at a predetermined frequency, the dielectric member has a flat plate shape that conforms to the surface of the roof panel, and the horizontal length of the dielectric member is 1 / 4 or more of the wavelength of the frequency.

6. The roof module according to claim 1, comprising a plurality of metal patches (6) which are flat metal conductors periodically arranged on the upper surface of the dielectric member, wherein the antenna is configured to operate at a predetermined frequency, and the plurality of metal patches are configured to resonate at the predetermined frequency.

7. The roof module according to claim 6, comprising a plurality of antennas, each operating at a different frequency, wherein the plurality of antennas are arranged within the recess at a predetermined distance from one another, a plurality of sets of dielectric units, each including a dielectric member and a conductive member, are arranged around the recess, the plurality of sets of dielectric units are arranged alongside the plurality of antennas, the dielectric unit includes a plurality of metal patches periodically arranged on the upper surface of the dielectric member, and the plurality of metal patches included in the dielectric unit are configured to resonate at the frequency at which the antenna adjacent to the dielectric unit operates.

8. An antenna set for use by being assembled into a hole (13) provided in a roof panel which is the exterior roof of a mobile body, comprising: a circuit module (5) on which an antenna is mounted; a metal antenna case (210) having an open top shape for closing the hole and housing the circuit module; and a dielectric member (2), which is a dielectric plate or dielectric sheet, arranged around the hole.

Images