Antenna set

Abstract

To provide a technology capable of improving the gain in a predetermined direction. [Solution] This antenna set is used by being attached to a roof panel that is provided with a main recess 91 and an inclined portion 914 that extends in a predetermined direction from the side portion 912 of the main recess and is formed so that its depth decreases as it moves away from the main recess. The antenna set comprises a substrate 1 on which an antenna 10 is mounted, which is housed in the main recess, and a dielectric member 2 which is a dielectric that covers at least a part of the inclined portion.

Description

[Technical Field]

[0001] The disclosure of this specification relates to an antenna set. [Background Art]

[0002] Patent Document 1 discloses a configuration for housing an antenna in a recess provided in the roof of a vehicle. As such, a technique for improving the aesthetic appearance of a vehicle by embedding the antenna in the vehicle roof is known. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2003-017916 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] When an antenna is mounted in a recess of a vehicle roof, radio waves radiated from the antenna are reflected by the wall surface of the recess and directed upward of the vehicle. This causes a problem that the gain in the horizontal direction of the vehicle decreases.

[0005] One object of the present disclosure is to provide a technique capable of improving gain in a predetermined direction. [Means for Solving the Problem]

[0006] The antenna set disclosed herein is An antenna set for use by being attached to a roof panel provided with a main recess and an inclined portion that extends from a side surface of the main recess in a predetermined direction and is formed such that depth thereof decreases as distance from the main recess increases, wherein a substrate (1) that is accommodated in the main recess and has an antenna (10) mounted thereon, and a dielectric member (2) that is a dielectric covering at least a part of the inclined portion, the antenna set comprising the dielectric member.

[0007] The roof panel on which the antenna set is used has a sloping portion extending from a main recess. In the antenna set of this disclosure, a dielectric member covers at least a portion of the sloping portion. Radio waves incident from the antenna onto the sloping portion are incident on the dielectric member covering the sloping portion. Some of the radio waves are repeatedly reflected within the dielectric member, propagate from the dielectric member in a predetermined direction, and are radiated from the tip of the dielectric member in the predetermined direction. Here, the tip refers to the end of the dielectric member in the predetermined direction. Therefore, this configuration makes it possible to improve the gain in the predetermined direction. [Brief explanation of the drawing]

[0008] [Figure 1] This is a conceptual diagram showing the mounting position of the antenna set. [Figure 2] This is a conceptual diagram showing the configuration of the antenna set. [Figure 3] This is a conceptual diagram showing the relative positions of the antenna sets. [Figure 4] This is a diagram showing a comparative example. [Figure 5] This diagram shows the gain when the antenna is activated. [Figure 6] This diagram shows the gain when the antenna is activated. [Figure 7] This diagram shows the gain when the antenna is activated. [Figure 8] This diagram shows the gain when the antenna is activated. [Figure 9] This is a diagram showing a modified example. [Figure 10] This is a diagram showing a modified example. [Figure 11] This is a diagram showing a modified example. [Figure 12] This is a diagram showing a modified example. [Figure 13] This is a diagram showing a modified example. [Figure 14] This is a diagram showing a modified example. [Figure 15] This is a diagram showing a modified example. [Figure 16]FIG. 4 is a diagram showing a modified example. [Figure 17] FIG. 5 is a diagram showing a modified example. [Figure 18] FIG. 6 is a diagram showing a modified example. [Figure 19] FIG. 7 is a diagram showing a modified example. [Figure 20] FIG. 8 is a conceptual diagram showing the configuration of an antenna set. [Figure 21] FIG. 9 is a conceptual diagram showing the positional relationship of the antenna set. [Figure 22] FIG. 10 is an enlarged conceptual diagram of a cover protrusion. [Figure 23] FIG. 11 is a diagram showing gain when the antenna is operated. [Figure 24] FIG. 12 is a diagram showing gain when the antenna is operated. [Figure 25] FIG. 13 is a conceptual diagram showing the positional relationship of the antenna set. [Figure 26] FIG. 14 is a cross-sectional view taken along line XXVI-XXVI of FIG. 25. [Figure 27] FIG. 15 is a cross-sectional view taken along line XXVII-XXVII of FIG. 25. [Figure 28] FIG. 16 is a diagram showing gain when the antenna is operated. [Figure 29] FIG. 17 is a diagram showing gain when the antenna is operated. [Figure 30] FIG. 18 is a conceptual diagram showing the configuration of an antenna set. [Figure 31] FIG. 19 is an enlarged conceptual diagram of a cover protrusion. [Figure 32] FIG. 20 is a diagram showing gain when the antenna is operated. [Figure 33] FIG. 21 is a diagram showing gain when the antenna is operated. DETAILED DESCRIPTION OF EMBODIMENTS

[0009] 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.

[0010] In the following descriptions, components with the same function may be given the same reference numeral, and their specific descriptions may be omitted. Similarly, components with the same function may be given the same or similar names, and their specific descriptions may be omitted. If only a part of the configuration is mentioned, the descriptions provided elsewhere may apply to the remaining parts.

[0011] (First Embodiment) The antenna set 100 will be explained using Figures 1, 2, and 3. The antenna set 100 is a unit consisting of a substrate 1 on which the antenna 10 is mounted, a dielectric member 2, and a resin cover 3. The antenna set 100 is used by being attached to the roof panel RP. Although Figures 2 and 3 are not cross-sectional views, for convenience, the dielectric member 2 and the resin cover 3 are shown with a dielectric pattern hatched.

[0012] The roof panel RP is a component that provides the roof of 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 antenna set 100 is applied (hereinafter referred to as the applied vehicle) may be an electric vehicle such as a hybrid vehicle (HV) or an electric vehicle (BEV). The applied vehicle may also be an engine-powered 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. 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 lateral direction of the vehicle Hv. The X and Y directions are also the horizontal directions 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.

[0014] This section describes the roof panel RP to which the antenna set 100 is attached. The roof panel RP is an outer panel that makes up the roof portion of the vehicle Hv. The roof panel RP has the function of maintaining the overall strength of the vehicle body. The roof panel RP 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 RP is made of metal. The material of the roof panel RP may be an aluminum alloy, or glass may be used in part. The roof panel RP may also be painted. As an example, the roof panel RP is formed into a predetermined shape by pressing a metal sheet, such as a steel plate.

[0016] In this embodiment, the roof panel RP is a substantially rectangular flat plate when viewed from above. The roof panel RP has a gently curved shape in the X and Y directions. The roof panel RP has a panel surface RS. The roof panel RP may have any shape.

[0017] The roof panel RP has a metallic recess 90 with an opening facing upward. The recess 90 is the area where the substrate 1 is mounted. In this embodiment, the recess 90 is located behind the center of the panel. The center of the panel refers to the center of the roof panel RP in the longitudinal direction of the vehicle.

[0018] The recess 90 is formed by a main recess 91 and an inclined portion 914. The substrate 1 is placed in the main recess 9S1. The inclined portion 914 is configured to improve the gain of radio waves toward the front of the vehicle, as will be described later, and is formed in front of the main recess 91. The main recess 91 is provided with a hole for passing wiring or connectors for the substrate 1 to transmit signals, as will be described later. The main recess 91 is formed to widen upwards. That is, the main recess 91 has the shape of an inverted truncated square pyramid. The main recess 91 is formed by a bottom portion 911 and four side portions 912. As described above, the bottom portion 911 is smaller than the opening. In this embodiment, the bottom portion 911 and the side portions 912 are substantially planar in shape.

[0019] The side portion 912 is formed by a front side portion 912a positioned in the forward direction, a rear side portion 912b positioned in the rear direction, a right side portion positioned to the right, and a left side portion positioned to the left. The rear side portion 912b, the right side portion, and the left side portion are surfaces that are continuous with the panel surface RS. The front side portion 912a is a surface that is continuous with the inclined portion 914. The length of the front side portion 912a in the Z direction is shorter than that of the rear side portion 912b, the right side portion, and the left side portion.

[0020] The end of the front side portion 912a in the Z direction is also referred to as the front upper end portion 913a. The end of the rear side portion 912b in the Z direction is also referred to as the rear upper end portion 913b. The front upper end portion 913a is located in the Y direction relative to the lower end of the front side portion 912a. The rear upper end portion 913b is located in the -Y direction relative to the lower end of the rear side portion 912b.

[0021] The depth of the main recess 91 may be set arbitrarily. The depth of the main recess 91 may be set to a value such as 20 mm, 30 mm, or 40 mm. The length of the main recess 91 in the Y direction may also be set arbitrarily. The length of the main recess 91 in the Y direction may be set to a value such as 100 mm, 150 mm, or 200 mm.

[0022] The inclined portion 914 extends forward from the upper end (i.e., the front upper end portion 913a) of the front surface portion 912a of the main recess 91, and is formed such that its depth decreases as it moves away from the main recess 91. The inclined portion 914 is a surface that is continuous with the panel surface RS. The end of the inclined portion 914 in the Y direction is also referred to as the front inclined end 914a.

[0023] A circuit board 1 is placed within the main recess 91. The circuit board 1 is a circuit module that performs signal processing related to at least one of signal transmission and / or reception. The circuit board 1 is configured to perform at least one of modulation, demodulation, frequency conversion, amplification, digital-to-analog conversion, and detection. The circuit board 1 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 board 1 processes the signal received by the antenna 10 and transmits it to the ECU or the like.

[0024] The antenna 10 mounted on the circuit board 1 is, for example, a dipole antenna. Antenna 10 may also be a monopole antenna, an inverted L antenna, an inverted F antenna, or an array antenna combining multiple antennas. In this embodiment, there is one antenna 10.

[0025] Antenna 10 is configured to operate at a predetermined frequency. Hereinafter, the frequency that antenna 10 transmits or receives will be referred to as the target frequency. The target frequency may also be referred to as the operating frequency. Antenna 10 can transmit and receive radio waves not only at the target frequency but also at frequencies within a predetermined range determined with respect to the target frequency. In this disclosure, the frequency band that antenna 10 can transmit or receive will also be referred to as the target frequency band.

[0026] 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.

[0027] 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."

[0028] The antenna 10 in 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 board 1 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.

[0029] A dielectric member 2, which is a dielectric material, is arranged in the inclined portion 914. In this embodiment, the dielectric member 2 is arranged in front of the main recess 91 in the Y direction and connected to the front upper end portion 913a of the main recess 91. The dielectric member 2 is arranged in the Y direction when viewed from the substrate 1 (and consequently the antenna 10) placed in the main recess 91.

[0030] The Y direction is the longitudinal direction of the vehicle, but from another perspective, the Y direction may be understood as the co-location direction, which is the direction from the main recess 91 toward the dielectric member 2. Alternatively, the Y direction may be understood as the direction from the antenna 10 toward the dielectric member 2.

[0031] The dielectric member 2 has a reflectivity of a predetermined value or higher at its dielectric surface 2s, and is formed to guide the radio waves radiated from the antenna 10 forward through interfacial reflection. The dielectric surface 2s may also be referred to as the top surface.

[0032] The dielectric member 2 has a shape that fills the recess caused by the inclined portion 914 relative to the panel surface RS around the main recess 91. The dielectric member 2 is rectangular in top view. The dielectric member 2 is formed so that the dielectric surface 2s and the panel surface RS are continuously (smoothly) connected. In other words, the dielectric member 2 is formed so that the heights of the dielectric surface 2s and the panel surface RS in the Z direction are the same.

[0033] The end of the dielectric surface 2s in the -Y direction is described as the dielectric rear end 2b. The dielectric rear end 2b is adjacent to the resin cover 3, which will be described later. In this disclosure, "adjacent" means a state in which they are continuously or directly adjacent and in contact. "Adjacent" may be rephrased as "connected," etc. The end of the dielectric surface 2s in the Y direction is described as the dielectric front end 2a. The dielectric front end 2a may be understood as the tip of the dielectric member 2.

[0034] The dielectric member 2 is formed so that its thickness decreases towards the front. The dielectric member 2 in this embodiment has a bottom surface portion 21 that abuts against the inclined portion 914. The rear end of the bottom surface portion 21 is also referred to as the bottom rear end portion 21e. The bottom rear end portion 21e is also the main recess side end, which is the end adjacent to the front upper end portion 913a. The thickness in the Z direction from the dielectric rear end portion 2b to the bottom rear end portion 21e is also referred to as the resin thickness (D).

[0035] The resin thickness affects the gain of the antenna 10 in the Y direction. Specifically, within a certain range, the thicker the resin, the more the gain of the antenna 10 in the Y direction tends to improve. In this embodiment, the resin thickness is set to λ / 5. The resin thickness may be set arbitrarily. The resin thickness may be set to λ / 8 or more. The resin thickness may be values ​​such as 4 mm, 8 mm, or 12 mm.

[0036] In the following, the length of the dielectric member 2 in the Y direction will also be referred to as the first length (L). The first length is the length from the leading end 2a of the dielectric to the trailing end 2b of the dielectric. Similarly, the length of the dielectric member 2 in the X direction will also be referred to as the second length (W).

[0037] The first length affects the gain of the antenna 10 in the Y direction. Specifically, within a certain range, the longer the first length, the more the gain of the antenna 10 in the Y direction tends to improve. In this embodiment, the first length is set to 3λ. The first length may be set arbitrarily. The first length may be set to λ / 2 or more. The first length may be a value such as 40mm, 60mm, or 80mm. The second length affects the shape of the directivity of the antenna 10 in the horizontal direction. The second length may be set arbitrarily. The second length may be a value such as 500mm, 700mm, or 1000mm.

[0038] The material of dielectric member 2 may be set arbitrarily. In this embodiment, as an example, the material of dielectric member 2 is PP (Polypropylene) with a dielectric constant of 2.2. Alternatively, the material of 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 dielectric member 2. Dielectric member 2 is fixed to the panel surface RS by methods such as bonding with an adhesive, engagement, or fastening.

[0039] The resin cover 3 is a dielectric cover that covers the opening of the main recess 91 from above. The resin cover 3 has the function of protecting the substrate 1 and the antenna 10 from the external environment (wind and rain, etc.). The resin cover 3 has a substantially flat shape that follows the panel surface RS. The resin cover 3 is formed to connect continuously (smoothly) to the dielectric surface 2s and the panel surface RS. The resin cover 3 may be attached to the roof panel RP and the dielectric member 2 by screws, welding, adhesive, etc.

[0040] The material of the resin cover 3 may 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). The thickness of the resin cover 3 may be set arbitrarily. The thickness of the resin cover 3 may be 2 mm, 3 mm, 5 mm, etc.

[0041] <Operation of the first embodiment> This section describes the operation of this embodiment. The dielectric member 2 is positioned on the inclined portion 914. As a result, when the antenna 10 is activated, a portion of the radio waves radiated from the antenna 10 propagates into the dielectric member 2. Some of the radio waves incident on the dielectric member 2 are reflected within the dielectric member 2 at the interface between the dielectric surface 2s and the air, where the angle of incidence exceeds the Brewster angle. The radio waves propagating within the dielectric member 2 are then reflected at the interface between the bottom portion 21 and the inclined portion 914. In this way, some of the radio waves incident on the dielectric member 2 are repeatedly reflected at the interface between the dielectric surface 2s and the air, and at the interface between the bottom portion 21 and the inclined portion 914, and propagate forward. The thickness of the dielectric member 2 is formed to become thinner towards the front. Therefore, the radio waves are radiated forward from the tip of the dielectric member 2 (dielectric front end portion 2a). Consequently, this configuration makes it possible to improve the gain in the forward direction.

[0042] The effects of this embodiment will be explained using a comparative example. Figure 4 shows a comparative example. In the comparative example, a recess 81 is provided in the roof panel RP. In the comparative example, a substrate 1 on which the antenna 10 is mounted is placed in the recess 81. In the comparative example, a resin cover 3 is provided to cover the opening of the recess 81. In the comparative example, the inclined portion 914 and the dielectric member 2 are not provided.

[0043] Figure 5 shows the horizontal gain when antenna 10 is activated. Figure 6 shows the vertical gain when antenna 10 is activated. In Figures 5 and 6, solid lines show the results according to the configuration of this embodiment, and dashed lines show the results of the comparative example.

[0044] As shown in Figures 5 and 6, the configuration of this embodiment shows improved gain in the front of the vehicle compared to the comparative example. Furthermore, it was confirmed that the forward gain in the configuration of this embodiment is 0 dBi, which is higher than the gain of the comparative example (-6.2 dBi).

[0045] Figure 7 shows the simulation results when the first length (L) is changed. In Figure 7, the solid line shows the forward gain results with the configuration of this embodiment, and the dashed line shows the approximation curve of the solid line. The value of α in the figure is, for example, 100 mm or 120 mm, and is determined by the material of the dielectric member 2 and the target frequency. The gain of the comparative example was -6.2 dBi as described above. Compared to the case without dielectric member 2, it can be seen that an improvement in forward gain can be obtained when the first length is λ / 2 or more.

[0046] Figure 8 shows the simulation results when the resin thickness (D) is changed. The value of β in the figure is, for example, 10 mm or 20 mm, and is determined by the material of the dielectric member 2 and the target frequency. Compared to the case without dielectric member 2, it can be seen that an improvement in forward gain is obtained when the resin thickness is λ / 8 or more.

[0047] <Variation> The shape of the inclined portion 914 may be the shape shown in Figures 9 to 12. Although the figures 9 to 19, which show modified examples, are not cross-sectional views, for convenience, the dielectric material 2, the resin cover 3, and the metal cover 4 (described later) are shown with a dielectric pattern hatching. In Figures 9 to 12, the substrate 1 and antenna 10 are omitted. As shown in Figure 9, the inclined portion 914 may be curved. As shown in Figure 10, the inclined portion 914 may be curved with a protruding portion. As shown in Figure 11, the inclined portion 914 may have a shape with two stages of inclination. In other words, the inclined portion 914 may have a shape with two different gradients. As shown in Figure 12, the inclined portion 914 may be staircase-shaped with multiple steps.

[0048] The shape of the main recess 91 may be the shape shown in Figure 13. In Figure 13, the substrate 1 and antenna 10 are not shown. In this modified example, the side portion 912 is formed to be perpendicular to the panel surface RS.

[0049] The roof panel RP may be made of resin. In this case, as shown in Figure 14, a metal plate 915 may be placed between the bottom of the substrate 1 and the bottom portion 911. The metal plate 915 is a component that functions as a ground for the antenna 10 and the substrate 1.

[0050] The antenna set 100 may also be configured to include a metallic cover 4 instead of the resin cover 3 (Figure 15). In this modified configuration, since the upper part of the main recess 91 is covered by the metallic cover 4, radio waves radiated above and behind the main recess 91 can be propagated forward. This improves the forward gain.

[0051] The dielectric member 2 may have a shape that does not fill the recess created by the inclined portion 914, as shown in Figure 16. In Figure 16, the dielectric member 2 is plate-shaped. A gap may be formed between the dielectric member 2 and the inclined portion 914.

[0052] The operation of the antenna set 100 in the modified example shown in Figure 16 will be explained. When the antenna 10 is activated, a portion of the radio waves radiated from the antenna 10 propagates into the dielectric member 2. Some of the radio waves incident on the dielectric member 2 are reflected within the dielectric member 2 at the interface between the dielectric surface 2s and the air, with the angle of incidence exceeding the Brewster angle. The radio waves then repeatedly reflect at the interface between the dielectric member 2 and the air within the dielectric member 2, and are radiated forward from the tip of the dielectric member 2. In this way, the radio waves repeatedly reflect at the interface between the dielectric surface 2s and the air and propagate forward. Then, the radio waves are radiated forward from the tip of the dielectric member 2.

[0053] Furthermore, some of the radio waves emitted from the antenna 10 are reflected from the lower surface of the dielectric member 2 without entering the dielectric member 2. The radio waves are then reflected at the inclined portion 914. In this way, some of the radio waves are repeatedly reflected at the interface between the air and the dielectric member 2 and at the interface between the air and the inclined portion 914, and the radio waves are emitted forward from the tip of the dielectric member 2. As a result, it is possible to improve the forward gain in this modified example as well.

[0054] The dielectric member 2 may be formed by stacking a plurality of plate-shaped dielectrics, as shown in Figure 17. The plurality of plate-shaped dielectrics may be formed to fill the inclined portion 914. Alternatively, as shown in Figure 18, the dielectric member 2 may have a configuration comprising a dielectric base 22 and a plurality of dielectric support portions 23. The dielectric base 22 is a rectangular plate. The dielectric support portions 23 are members that support the dielectric base 22. The plurality of dielectric support portions 23 are arranged at predetermined intervals from each other in the Y direction.

[0055] As shown in Figure 19, the antenna set 100 may be configured such 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 Figure 19, the resin cover 3 has a base portion 30 and a cover extension portion 31. The base portion 30 is the part that covers the opening of the main recess 91. The base portion 30 has a shape corresponding to the opening of the main recess 91. The base portion 30 may be understood as the upper part of the resin cover 3 that is connected to the panel surface RS and the dielectric member 2.

[0056] The cover extension portion 31 extends from the base portion 30 in the Y direction and is a member that fills the recess caused by the inclined portion 914 with respect to the panel surface RS around the main recess 91. The cover extension portion 31 is formed so that it is continuously (smoothly) connected to the panel surface RS. In other words, the cover extension portion 31 is formed so that the height of the cover extension portion 31 and the panel surface RS in the Z direction are the same.

[0057] In this modified example, the cover extension portion 31 performs the function of the dielectric member 2 in the previously described embodiment. As a result, the gain in the forward direction is improved, similar to the previously described embodiment.

[0058] <Second Embodiment> A second embodiment will be described using Figures 20, 21, and 22. Although Figures 20 and 21 are not cross-sectional views, for convenience, the dielectric material hatching is applied to the dielectric member 2 and the resin cover 3. Hereafter, even in figures that are not cross-sectional views, the dielectric material hatching may be applied to clearly indicate the dielectric member 2 and the resin cover 3.

[0059] This embodiment differs from the first embodiment in that the resin cover 3 has a cover projection 32 that protrudes from the base 30 toward the interior of the main recess 91. In Figure 20, the hypothetical boundary between the base 30 and the cover projection 32 is shown by a dashed line. In this embodiment, the cover projection 32 is provided in a region located in the Y direction relative to the antenna 10. The cover projection 32 is adjacent to the dielectric member 2. The amount of protrusion of the cover projection 32 is formed to increase in thickness as it moves away from the antenna 10. The cover projection 32 has a protruding surface 32s which is the surface facing the antenna 10.

[0060] Figure 22 is a conceptual diagram showing an enlarged view of the area around the cover protrusion 32. The angle of incidence θ1 when radio waves radiated from the antenna are incident on the protruding surface 32s is shown in Figure 22. The angle of incidence θ1 is the angle formed by the line connecting the normal (vertical line) of the protruding surface 32s and the direction of propagation of the radio waves radiated from the antenna 10. The angle of incidence θ2 is the angle formed by the radio waves incident on the protruding surface 32s and the normal to the surface 3s of the resin cover 3. The angle of incidence θ2 is the angle formed by the line connecting the normal (vertical line) of the surface 3s and the direction of propagation of the radio waves.

[0061] If the protrusion of the cover projection 32 is made thicker as it moves away from the antenna 10, the incidence angle θ1 of the radio waves incident on the cover projection 32 from the antenna 10 becomes smaller than in a configuration without the cover projection 32. When the incidence angle θ1 becomes smaller, the incidence angle θ2 of the radio waves incident on the air from the resin cover 3 becomes larger. As a result, some of the radio waves incident on the cover projection 32 have an incidence angle θ2 that exceeds the Brewster angle, undergo total internal reflection at the interface between the resin cover 3 and the air, and repeatedly reflect forward within the resin cover 3. The radio waves then incident on the adjacent dielectric member 2. Thus, according to the configuration of this embodiment, a portion of the radio waves propagating above the main recess 91 can be propagated forward. Therefore, the forward gain can be improved.

[0062] Figure 23 shows the horizontal gain when antenna 10 is activated. Figure 24 shows the vertical gain when antenna 10 is activated. In Figures 23 and 24, the solid lines show the results for the configuration of the second embodiment, and the dashed lines show the results for the first embodiment. As shown in Figures 23 and 24, it was confirmed that the forward gain is also high in the configuration of this embodiment.

[0063] <Variation> As shown in Figures 25, 26, and 27, the cover protrusion 32 may be provided on the entire lower surface of the base 30. In this embodiment, two dielectric members 2 are provided in the Y direction and the -Y direction. The dielectric member 2 is semicircular in top view. According to this modified example, it is possible to suppress radio waves propagating above the main recess 91 and improve the gain in the front and rear directions.

[0064] Figure 28 shows the horizontal gain when antenna 10 is activated. Figure 29 shows the vertical gain when antenna 10 is activated. In Figures 28 and 29, the solid lines show the results with the configuration of this modified example, and the dashed lines show the results with the first embodiment. As shown in Figures 28 and 29, it was confirmed that the forward and rear gains are high with the configuration of this embodiment.

[0065] <Third Embodiment> This embodiment will be described with reference to Figures 30 and 31. This embodiment differs from the second embodiment in that the cover projection 32 has a plurality of protruding portions 321 that are adjacent to each other and arranged in the Y direction. The protruding portions have opposing surfaces 321s that face the antenna 10.

[0066] Figure 31 is a conceptual diagram showing an enlarged view of the area around the cover protrusion 32. The angle of incidence θ3 when radio waves radiated from the antenna are incident on the opposing surface 321s is shown in Figure 31. The angle of incidence θ3 is the angle formed by the line connecting the normal to the opposing surface 321s and the direction of propagation of the radio waves radiated from the antenna 10. The opposing surface 321s is formed such that the angle of incidence θ3 becomes smaller the closer the protrusion 321 is to the antenna 10.

[0067] As the incidence angle θ3 of the radio waves incident on the protruding portion 321 from the antenna 10 decreases, the incidence angle θ2 of the radio waves incident on the air from the resin cover 3 increases. Some of the radio waves, with an incidence angle θ2 exceeding the Brewster angle, undergo total internal reflection at the interface between the resin cover 3 and the air, repeatedly reflect in the Y direction within the resin cover 3, and incident on the adjacent dielectric member 2.

[0068] By directing a portion of the upward-propagating radio waves forward instead of upward, an improvement in the gain in the Y direction can be expected. Here, the radio waves propagating upward are concentrated closer to the antenna 10 at the protruding portion 321. Therefore, by forming the opposing surface 321s such that the incident angle θ3 is smaller closer to the antenna 10 at the protruding portion 321, a portion of the upward-propagating radio waves can be directed forward. This improves the gain in the forward direction.

[0069] Figure 32 shows the horizontal gain when antenna 10 is activated. Figure 33 shows the vertical gain when antenna 10 is activated. In Figures 32 and 33, the solid lines show the results for the configuration of the third embodiment, and the dashed lines show the results for the first embodiment. As shown in Figures 32 and 33, it was confirmed that the forward gain is also high in the configuration of this embodiment.

[0070] <Other variations> The recess 90 may be provided at any position on the vehicle Hv. The recess 90 may be provided in front of the center of the panel. In addition, multiple recesses 90 may be provided.

[0071] The heights of the dielectric surface 2s and the panel surface RS in the Z direction do not have to be the same. In the Z direction, the dielectric surface 2s may be higher or lower than the panel surface RS.

[0072] The antenna set 100 may be configured without a resin cover 3 or a metal cover 4.

[0073] The above describes an embodiment in which the inclined portion is positioned in front of the main recess, but it is not limited to this. The inclined portion 914 may be formed in a predetermined direction, which is the direction in which the directivity is to be directed. The above mainly describes the case in which the predetermined direction is the Y direction (forward direction), but the predetermined direction may be to the right, left, or rear. The description of "forward" in relation to the propagation of radio waves above may be understood as being replaced with "predetermined direction". The inclined portion 914 and the dielectric member 2 are configured to guide radio waves traveling diagonally upward in a predetermined direction parallel to the horizontal plane. [Explanation of Symbols]

[0074] 1…Substrate, 2…Dielectric material, 2s…Dielectric surface, 3…Resin cover, 3s…Surface, 4…Metal cover, 10…Antenna, 21e…Main recess side end, 30…Base, 31…Cover extension, 32…Cover protrusion, 90…Recess, 91…Main recess, 100…Antenna set, 321…Protruding part, 321s…Opposite surface, 914…Inclined part, RS…Panel surface, RP…Roof panel

Claims

1. An antenna set used by being attached to a roof panel, which is provided with a main recess and an inclined portion that extends in a predetermined direction from the side surface of the main recess and is formed such that its depth decreases as it moves away from the main recess, A substrate (1) on which an antenna (10) is mounted is housed in the main recess, An antenna set comprising a dielectric member (2) which is a dielectric that covers at least a part of the inclined portion.

2. The antenna set according to claim 1, wherein the dielectric member has a reflectance of a predetermined value or more on its surface and is formed to guide the radio waves radiated from the antenna in the predetermined direction by interfacial reflection.

3. The dielectric member is It has a shape that fills the recess caused by the inclined portion on the surface of the roof panel around the main recess, The thickness of the dielectric member is formed to become thinner in the predetermined direction. The antenna set according to claim 1, further comprising a bottom surface that contacts the inclined portion.

4. The antenna set according to claim 1, further comprising a dielectric resin cover (3) that covers the opening of the main recess from above.

5. The aforementioned resin cover is A base portion (30) having a shape corresponding to the opening, It has a cover projection (32) that protrudes from the base toward the interior of the main recess, The cover protrusion is provided in a position adjacent to the dielectric member, The antenna set according to claim 4, wherein the amount of protrusion of the cover convex portion is formed to increase in thickness as it moves away from the antenna.

6. The aforementioned resin cover is A base portion (30) having a shape corresponding to the opening, It has a cover projection (32) that protrudes from the base toward the interior of the main recess, The aforementioned cover protrusion is, It is formed adjacent to the dielectric member, It has a plurality of protruding portions (321) that are adjacent to each other and arranged in the predetermined direction, The aforementioned protruding portion has a facing surface which is the surface facing the antenna, The antenna set according to claim 4, wherein the opposing surface is formed such that the angle of incidence of radio waves radiated from the antenna that enters the opposing surface becomes smaller as the protruding portion is closer to the antenna.

7. The resin cover has a cover extension portion (31) that is shaped to fill the recess caused by the inclined portion, The antenna set according to claim 4, wherein the dielectric member is the extended portion of the cover.

8. The antenna set according to claim 1, further comprising a metallic cover (4) that covers the opening of the main recess from above.

9. The aforementioned antenna is configured to operate at a predetermined frequency. The antenna set according to claim 3, wherein the length of the dielectric member in the predetermined direction is 1 / 2 or more of the wavelength of the frequency.

10. The aforementioned antenna is configured to operate at a predetermined frequency. Of the ends of the dielectric member, the end adjacent to the end of the side portion in the predetermined direction is defined as the main recess side end (21e). The antenna set according to claim 3, wherein the thickness of the dielectric member at the end on the main recess side is 1 / 8 or more of the wavelength of the frequency.

Images