Antenna device

Abstract

This antenna device 100 comprises a base 101, and a plurality of antennas arranged on the base 101. The plurality of antennas include a GNSS antenna 60 that is compatible with radio waves of a first frequency band, and an FM antenna 50 that is compatible with radio waves of a second frequency band that is lower than the first frequency band. The GNSS antenna 60 includes a flat portion. The FM antenna 50 includes an element 500. The element 500 includes a first slit S1 extending along the Y direction from the end near where the GNSS antenna 60 is positioned. The Y-direction length of the first slit S1 is 1 / 16 or more of the wavelength of the first frequency band.

Description

Antenna device

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

[0002] In Patent Document 1, an antenna device including a plurality of antennas is arranged inside a recess formed in a roof of a vehicle.

[0003] Japanese Unexamined Patent Publication No. 2022-099411

[0004] Incidentally, when an antenna device includes a plurality of antennas, for example, depending on the arrangement pattern of the plurality of antennas, characteristics of any one of the antennas may deteriorate.

[0005] An example of an object of the present invention is to suppress deterioration of characteristics of an antenna included in an antenna device. Other objects of the present invention will become apparent from the description of the present specification.

[0006] One aspect of the present invention is an antenna device including a base and a plurality of antennas arranged on the base, wherein the plurality of antennas include a first antenna compatible with radio waves in a first frequency band, and a second antenna compatible with radio waves in a second frequency band lower than the first frequency band, the first antenna includes a flat portion, the second antenna includes an element, the element includes a first slit extending along a first direction from an end on a side where the first antenna is located, and a length of the first slit along the first direction is 1 / 16 or more of a wavelength of the first frequency band.

[0007] According to the above aspect of the present invention, deterioration of characteristics of an antenna included in an antenna device can be suppressed.

[0008] This is a side view (partial cross-sectional view) of vehicle 1 on which the antenna device 100 is installed. This is an exploded perspective view of the antenna device 100. This is a plan view of the antenna device 100. This is a diagram showing an example of the signal processing device 80. This is a diagram for explaining the characteristics of the GNSS antenna 60. This is a diagram for explaining the characteristics of the GNSS antenna 60. This is a side view of the antenna device 120 placed on frame 5, which is a plan view of the antenna device 110. This is a perspective view showing part of frame 5 and part of antenna device 130. This is a graph showing the directivity pattern of the V2X antenna 20. This is a perspective view showing part of frame 5 and part of antenna device 140. This is a graph showing the directivity pattern of the V2X antenna 20. This is a perspective view showing part of frame 5 and part of antenna device 150. This is a graph showing the directivity patterns of V2X antennas 20 and 151. This is a perspective view showing part of frame 5 and antenna device 160. This is a graph showing the directivity patterns of V2X antennas 20A and 20B. This is a graph showing the ratio of the distance between antennas to the number of data points. This is a perspective view showing a portion of the antenna device 300. This is a cross-sectional view taken along line A-A in Figure 18. This is a cross-sectional view showing antenna device 300A. This is a perspective view showing a portion of the antenna device 310. This is a cross-sectional view taken along line B-B in Figure 21. This is a perspective view showing antenna device 310A. This is a plan view showing a portion of the antenna device 320. This is a plan view showing a portion of the antenna device 330. This is a cross-sectional view taken along line C-C in Figure 25. This is a plan view showing antenna device 330A. This is a cross-sectional view showing portions of antenna devices 340 and 340A.

[0009] The following matters become clear from this specification and the accompanying drawings:

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The same or equivalent components, members, etc. shown in each drawing are denoted by the same reference numerals, and redundant explanations will be omitted as appropriate.

[0011] ====Direction and Vehicle 1==== Figure 1 is a side view (partial cross-sectional view) of vehicle 1 on which the antenna device 100 is located.

[0012] <<Definition of Direction, etc.>> First, the direction, etc. of the antenna device 100 are defined with reference to Figure 1.

[0013] As shown in Figure 1, the direction forward as viewed from the driver's seat 2 of the vehicle 1 on which the antenna device 100 is located is defined as the +X direction (forward direction) of the antenna device 100, the direction left as viewed from the driver's seat 2 of the vehicle 1 is defined as the +Y direction (left direction) of the antenna device 100, and the direction upward as viewed from the driver's seat 2 of the vehicle 1 is defined as the +Z direction (upward direction) of the antenna device 100. The opposite directions of the +X direction, +Y direction, and +Z direction are defined as the -X direction (rear direction), -Y direction (right direction), and -Z direction (downward direction), respectively.

[0014] Each of the +X, -X, +Y, -Y, +Z, and -Z directions is a unidirectional direction (a direction with a fixed orientation). Furthermore, a direction that is not unidirectional, but rather both the +X and -X directions, may simply be referred to as the "X direction." Similarly, both the +Y and -Y directions may simply be referred to as the "Y direction." Also, both the +Z and -Z directions may simply be referred to as the "Z direction." In addition, in this embodiment, the +Z direction may be referred to as "upward."

[0015] In Figure 1, the +X, +Y, and +Z directions are represented by line segments with arrows to facilitate understanding of the direction of the antenna device 100. Note that the intersection of these line segments with arrows does not represent the coordinate origin.

[0016] Unless otherwise specified, the definitions of directions and other terms described above are common to other embodiments of this specification.

[0017] <<Vehicle 1>> As shown in Figure 1, an antenna device 100 is arranged in the space above the passenger compartment of Vehicle 1. Here, the configuration in which the antenna device 100 is arranged in Vehicle 1 is not limited to the configuration in which it is attached to Vehicle 1, but also includes the configuration in which it is brought into Vehicle 1 and used within Vehicle 1. Furthermore, "vehicle" means a vehicle with wheels, and examples include ordinary automobiles such as passenger cars, buses, and trucks, motorcycles and other two-wheeled vehicles, and special vehicles (industrial vehicles) such as tractors and bulldozers.

[0018] Between the interior ceiling 3 of the vehicle 1 and the roof panel 4, a frame 5, which is a structural component of the vehicle 1, is positioned. The frame 5 is made of a conductor (for example, metal), including roof side rails and reinforcements. In addition, a recess 6 is formed in a part of the frame 5 in this embodiment, where the antenna device 100 is positioned. In this embodiment, the antenna device 100 is positioned inside the recess 6, which is made of a conductor.

[0019] The recess 6 is located in the space between the interior ceiling 3 and the roof panel 4. The recess 6 extends along the Y direction of the vehicle 1 (i.e., the width direction of the vehicle 1), and the upper part of the recess 6 is covered, for example, by the roof panel 4. Although not shown in Figure 1, when viewed from the +Z direction, the length of the recess 6 in the Y direction is longer than the length of the recess 6 in the X direction. However, the shape of the recess 6 is not limited to this example, and for example, the length of the recess 6 in the Y direction may be shorter than the length of the recess 6 in the X direction.

[0020] Furthermore, the object on which the antenna device 100 is placed is not limited to the vehicle 1. That is, the antenna device 100 may be placed inside a recess (not shown) formed of a different conductor from the frame 5 of the vehicle 1.

[0021] <<Antenna Device 100>> Figure 2 is an exploded perspective view of the antenna device 100, and Figure 3 is a plan view of the antenna device 100. Note that in Figure 3, the cover 102 of the antenna device 100 is omitted for convenience.

[0022] The antenna device 100 consists of a base 101, a cover 102, and a plurality of antennas (described later).

[0023] The base 101 is made of metal. However, the base 101 may be made of metal and an insulating resin.

[0024] The cover 102 is formed of an insulating resin such as PC resin, ASA resin, PC / ASA resin composition, or ABS resin. However, the cover 102 may be formed of a material other than an insulating resin and a material that transmits radio waves.

[0025] Furthermore, the cover 102 may be composed of an insulating resin portion and a portion made of a material other than an insulating resin that transmits radio waves. In addition, a part of the cover 102 may be made of a conductive material or a material that does not transmit radio waves. In other words, the cover 102 may be formed by freely combining desired materials.

[0026] When viewed from the +Z direction, the base 101 has a roughly rectangular shape with a pair of short sides substantially parallel to the X direction and a pair of long sides substantially parallel to the Y direction. However, the shape of the base 101 when viewed from the +Z direction is not limited to this example. Hereafter, the view from the +Z direction will also be referred to as the "plan view".

[0027] Here, a roughly rectangular shape is included in a roughly quadrilateral shape. A "roughly quadrilateral shape" refers to a shape consisting of four sides, including, for example, a square or a rectangle, and may have at least some corners cut diagonally to the sides. In addition, a "roughly quadrilateral shape" may have notches (recesses) or protrusions (convex parts) formed on some of its sides.

[0028] The cover 102 is a component (a so-called radome) that covers the base 101 and, together with the base 101, forms a housing space in which multiple antennas are housed. The cover 102 has a rectangular box shape. When the cover 102, located on the +Z direction side, is attached to the base 101, located on the -Z direction side, multiple antennas are housed in the housing space between the base 101 and the cover 102. The base 101 and the cover 102 are attached to each other by a desired mounting means such as screw fastening, snap fitting, welding, or adhesive. The cover 102 may cover a part of the base 101, or the cover 102 may be absent altogether.

[0029] The antennas included in the antenna device 100 are, for example, a TEL antenna 10, a V2X antenna 20, an SXM antenna 30, an AM antenna 40, an FM antenna 50, and a GNSS antenna 60. The antennas included in the antenna device 100 may also include antennas other than those listed above.

[0030] The TEL antenna 10 is, for example, an antenna for mobile communications in the 699 MHz to 5000 MHz band for GSM, UMTS, LTE, and 5G. However, the TEL antenna 10 is not limited to this, and may support radio waves in some frequency bands of GSM, UMTS, LTE, and 5G (for example, only for 5G), or it may support radio waves in frequency bands other than the 699 MHz to 5000 MHz band.

[0031] The V2X antenna 20 is an antenna that corresponds to radio waves used in V2X (Vehicle to Everything: vehicle-to-vehicle communication, vehicle-to-infrastructure communication), and is formed as a monopole antenna. However, the V2X antenna 20 may be formed in other antenna forms such as a dipole antenna, loop antenna, collinear antenna, or bowtie antenna.

[0032] The SXM antenna 30 is a planar antenna (patch antenna) that corresponds to SXM (Sirius XM) radio waves for satellite radio broadcasting in the 2320 MHz to 2345 MHz band, for example.

[0033] The AM antenna 40 is, for example, an antenna that is compatible with AM broadcasting radio waves in the 522 kHz to 1710 kHz band.

[0034] The FM antenna 50 is, for example, an antenna that corresponds to radio waves for FM broadcasting in the 76 MHz to 108 MHz band. The FM antenna 50 is composed of an FM antenna element 500 corresponding to a capacitively charged element and a coil (not shown). Details of the FM antenna element 500 will be described later.

[0035] Figure 4 shows an example of a signal processing device 80 that processes signals from an AM antenna 40 and an FM antenna 50. The signal processing device 80 is composed of an AM amplifier 800, an FM amplifier 801, a combiner 802, a receiver 803, signal lines 810, 811, and a cable 812. In this embodiment, the signal processing device 80 is arranged, for example, on the same substrate as the AM amplifier 800, FM amplifier 801, combiner 802, and signal lines 810, 811. The signal lines 810, 811 may be conductor patterns formed on the substrate, or they may be cables or the like.

[0036] In this embodiment, the signal processing device 80 is, for example, located on the -Z side of the base 101, but is not limited to this. For example, the signal processing device 80 may be installed in the space housing the antenna device 100. Also, the receiver 803 may be installed inside the recess 6 where the antenna device 100 is located, or it may be installed outside the recess 6.

[0037] In some cases, the antenna device 100 may use common elements for the AM antenna 40 and the FM antenna 50, and separate the AM broadcast signal and the FM broadcast signal in the circuit of the signal processing device 80. In this case, a demultiplexing loss occurs when the signals are separated. On the other hand, by adopting a structure in which the elements of the AM antenna 40 and the FM antenna 50 are separate, as in this embodiment, the demultiplexing loss can be reduced.

[0038] The AM amplifier 800 is a circuit that amplifies a signal corresponding to the radio waves received by the AM antenna 40, and the FM amplifier 801 is a circuit that amplifies a signal corresponding to the radio waves received by the FM antenna 50. The signals from the AM amplifier 800 and the FM amplifier 801 are transmitted to the combiner 802 via signal lines 810 and 811 formed on a circuit board (not shown).

[0039] The combiner 802 combines the signal from the AM amplifier 800 and the signal from the FM amplifier 801, and then transmits it to the receiver 803 via cable 812. The receiver 803 outputs the signal from the combiner 802 to the audio amplifier (not shown) of the vehicle 1. Thus, in this embodiment, the signals from the AM antenna 40 and the FM antenna 50 are combined and then processed by the receiver 803.

[0040] If the distance between the AM antenna 40 and the FM antenna 50 at the base 101 increases, then the lengths of the signal lines 810, 811 and cable 812 will also increase. As a result, the signal received by the receiver 803 may be attenuated. Therefore, as shown in Figures 2 and 3, it is preferable to arrange the AM antenna 40 and the FM antenna 50 so that they are adjacent to each other at the base 101.

[0041] Furthermore, if the signal processing device 80, in which the AM amplifier 800, the FM amplifier 801, and the synthesizer 802 are arranged on the same substrate as described above, is used, the size of the signal processing device 80 can be reduced. In this case, the AM antenna 40 and the FM antenna 50 can be arranged closer to each other.

[0042] The GNSS antenna 60 shown in FIG. 2 and FIG. 3 is a planar antenna (patch antenna) compatible with radio waves of the Global Navigation Satellite System (GNSS). The GNSS antenna 60 is compatible with radio waves in two frequency bands, for example, the L1 band (1559 MHz to 1610 MHz band) and the L5 band (1164 MHz to 1214 MHz band). The radiating element of the GNSS antenna 60 corresponds to the "planar portion" of the planar antenna.

[0043] However, the communication standards and frequency bands supported by the GNSS antenna 60 are not limited to those described above, and other communication standards and frequency bands may be used. Further, the frequency bands of radio waves supported by the GNSS antenna 60 may be other than the combination of the two frequency bands of the L1 band and the L5 band. For example, the frequency bands of radio waves supported by the GNSS antenna 60 may be a combination of two frequency bands, the L1 band and the L2 (1212 MHz to 1254 MHz band) band, or may be a combination of three frequency bands, the L1 band, the L2 band and the L5 band.

[0044] Furthermore, the frequency bands of radio waves supported by the GNSS antenna 60 may include the L6 band (1273 MHz to 1284 MHz band) obtained by further adding correction satellite signals to the L1 band, the L2 band and the L5 band, and the L band (1525 MHz to 1559 MHz band). The frequency bands of radio waves supported by the GNSS antenna 60 are not limited to the combination of the specific plurality of frequency bands described above, and may be a combination of any plurality of frequency bands.

[0045] In this embodiment, the TEL antenna 10, V2X antenna 20, SXM antenna 30, AM antenna 40, FM antenna 50, and GNSS antenna 60 are arranged on the +Z direction side (upper surface side) of the base 101. When viewed from the +Z direction side, the TEL antenna 10, V2X antenna 20, SXM antenna 30, AM antenna 40, FM antenna 50, and GNSS antenna 60 are arranged in this order from the +Y direction side to the -Y direction side.

[0046] However, the arrangement of the TEL antenna 10, V2X antenna 20, SXM antenna 30, AM antenna 40, FM antenna 50, and GNSS antenna 60 is not limited to this example. Further, the antenna device 100 may include only some of the plurality of antennas shown in FIG. 2, and may further include an antenna other than the plurality of antennas shown in FIG. 2.

[0047] <<Regarding the FM antenna element 500 of the FM antenna 50>> Here, the FM antenna element 500 of the FM antenna 50 will be described with reference to FIG. 3. The FM antenna element 500 is a so-called capacitive loading element, and is a metal plate that resonates at a corresponding frequency of the FM antenna 50 together with an unshown coil electrically connected to the FM antenna element 500. In this embodiment, the FM antenna element 500 is, for example, a substantially quadrilateral metal plate with a side length of about 100 mm in the X direction and a side length of about 170 mm in the Y direction, but is not limited thereto, and may be a metal plate of other shapes such as an ellipse. Further, the FM antenna element 500 is not limited to a metal plate, and may be a substrate with a conductor pattern drawn thereon, or the like.

[0048] Incidentally, in this embodiment, since the FM antenna 50 and the GNSS antenna 60 are arranged adjacent to each other, the relatively large metal FM antenna element 500 is arranged near the GNSS antenna 60. As described above, the wavelength corresponding to the center frequency of the L5 band of the GNSS antenna 60 (hereinafter referred to as wavelength λ) is about 273 mm, and the length of the FM antenna element 500 in the longitudinal direction is longer than about 136 mm which is 1 / 2 of the wavelength λ.

[0049] Generally, if a metal plate larger than half the wavelength of the frequency band that the GNSS antenna 60 operates on is placed near the GNSS antenna 60, a current in the frequency band that the GNSS antenna 60 operates on may be generated in the metal plate. This can reduce the zenith gain of the GNSS antenna 60.

[0050] Therefore, in this embodiment, multiple slits are provided in the FM antenna element 500 to suppress the decrease in the gain of the GNSS antenna 60 in the zenith direction. Specifically, as shown in the area enclosed by the dotted line in Figure 3, the FM antenna element 500 has slit S1, two slits S2, and two slits S3. Here, "slit" refers to a notch in which one end is closed and the other end is open.

[0051] Here, half of the wavelength λ is approximately 136 mm, but in the antenna device 100, any electrical length corresponding to half of the wavelength λ is acceptable. Specifically, in the antenna device 100, the FM antenna element 500 may be affected by dielectric materials (not shown) arranged around it, such as the cover 102. For this reason, in the antenna device 100, the physical length with respect to the wavelength λ may differ from the length calculated from, for example, the center frequency of the L5 band.

[0052] The slit S1 has an open end E1 on the outer edge of the -Y side of the FM antenna element 500 (i.e., the -Y side), and is a notch extending along the Y direction from the open end E1. Furthermore, the shape of the slit S1 is, for example, a quadrilateral with width W1 and length L1 when viewed in a plan view of the FM antenna element 500 from the +Z direction.

[0053] The shape of the slit S1 may be a curve or zigzag shape other than a quadrilateral. The same applies to the shapes of slits S2 and S3. In addition, if the width W1 of the slit S1 is increased, the gain of the FM antenna 50 decreases, and if it is decreased, it becomes difficult to process the slit S1. Therefore, the width W1 of the slit S1 is adjusted appropriately considering performance and processability. The same applies to slits S2 and S3.

[0054] In this embodiment, the open end E1 is located approximately at the center of the side of the FM antenna element 500 that extends in the X direction on the -Y side, but the open end E1 may be located at other positions. The length L1 in this embodiment is, for example, 1 / 4 of the wavelength λ.

[0055] Each of the two slits S2 has an open end E2 at the outer edge in the width direction of the FM antenna element 500, and extends from the open end E2 toward the center in the width direction of the FM antenna element 500. The shape of the slit S2 is, for example, a quadrilateral with width W2 and length L2 when viewed in a plan view of the FM antenna element 500 from the +Z direction. In this embodiment, the length L2 is, for example, 1 / 8 of the wavelength λ.

[0056] In this embodiment, the open end E2 is located at a position 1 / 4 of the wavelength λ from the -Y side of the FM antenna element 500. That is, the length along the Y direction from the -Y end of the FM antenna element 500 to the open end E2 is 1 / 4 of the wavelength λ. However, the length along the Y direction from the -Y end of the FM antenna element 500 to the open end E2 is not limited to this.

[0057] Each of the two slits S3 has an open end E3 at the outer edge in the width direction of the FM antenna element 500, and extends from the open end E3 toward the center in the width direction of the FM antenna element 500. The shape of the slit S3 is, for example, a quadrilateral with width W3 and length L3 when viewed from the +Z direction in a plan view of the FM antenna element 500. In this embodiment, the shape of slit S2 and the shape of slit S3 are the same, but are not limited to this, and for example, the length L3 of slit S3 may be shorter than the length L2 of slit S2.

[0058] In this embodiment, the open end E3 is located at a position that is 1 / 4 of the wavelength λ from the open end E2. That is, the length along the Y direction from the open end E3 to the open end E2 is 1 / 4 of the wavelength λ. However, the length along the Y direction from the open end E3 to the open end E2 is not limited to this.

[0059] In this embodiment, the FM antenna element 500 was provided with three slits S1 to S3, but the FM antenna element 500 may be provided with four or more slits. For example, the FM antenna element 500 may have an open end at its outer edge in the width direction, and may also have a slit extending from the open end toward the center in the width direction of the FM antenna element 500, which is on the +Y side of slit S3.

[0060] Furthermore, the FM antenna element 500 may be positioned so that its -Y side is adjacent to the GNSS antenna 60 and its +Y side is adjacent to another patch antenna. In this case, the FM antenna element 500 may have an open end at its outer edge on the +Y side (i.e., the +Y side) and a slit extending along the Y direction from that open end.

[0061] <<Regarding the length L1 of slit S1>> Now, with reference to Figure 5, the characteristics of the GNSS antenna 60 will be explained. Figure 5 is a diagram showing the relationship between the length L1 of slit S1 and the characteristics of the GNSS antenna 60. Specifically, Figure 5 is an example of simulation results for the case where the FM antenna element 500 has no slits and the case where it has only slit S1. Note that "the FM antenna element 500 has no slits" means that the FM antenna element 500 does not have any slits S1 to S3.

[0062] As shown in Figure 5, compared to the case without a slit (solid line in Figure 5), gradually increasing the length L1 of the slit S1 of the FM antenna element 500 improves the overall gain of the GNSS antenna 60 at high elevation angles (e.g., 60° to 90°). Thus, even if the FM antenna element 500 only has a slit S1, the gain of the GNSS antenna 60 at high elevation angles can be improved by setting the length L1 of the slit S1 to, for example, 1 / 16λ or more.

[0063] By the way, when the FM antenna 50 and the GNSS antenna 60 are arranged adjacent to each other as in this embodiment, current from the GNSS antenna 60 tends to flow through the outer edge of the FM antenna element 500. Therefore, as shown in Figure 5, by having at least a slit S1 in the FM antenna element 500, it is possible to suppress the generation of current in the frequency band corresponding to the GNSS antenna 60 in the FM antenna element 500. As a result, as described above, the gain of the GNSS antenna 60, especially at high elevation angles, can be improved.

[0064] <<Regarding the combination of slits S1 to S3>> Figure 6 shows an example of the simulation results of the characteristics of the GNSS antenna 60 when the number of slits in the FM antenna element 500 is changed. In Figure 6, the case where the FM antenna element 500 has no slits is referred to as "no slits," and the case where the FM antenna element 500 has only slit S1 is referred to as "slit S1." In Figure 6, the length L1 of slit S1 is 1 / 4 of the wavelength λ.

[0065] Furthermore, in Figure 6, when the FM antenna element 500 has slits S1 and S2, they are referred to as "slits S1 and S2," and when the FM antenna element 500 has slits S1 to S3, they are referred to as "slits S1 to S3."

[0066] As shown in Figure 6, compared to the case where the FM antenna element 500 does not have slits, the high elevation angle gain of the GNSS antenna 60 can be improved when slits S1 and S2 and slits S1 to S3 are present.

[0067] As shown in Figure 6, the FM antenna element 500 has slits S2 and S3 in addition to slit S1, which suppresses the generation of current in the frequency band corresponding to the GNSS antenna 60 in the FM antenna element 500. Therefore, as described above, the gain of the GNSS antenna 60, especially at high elevation angles, can be improved.

[0068] In this case, in the FM antenna element 500, for example, the smaller the area partitioned by slit S1 and slit S2, and slit S2 and slit S3, the less likely the GNSS antenna 60 is to generate current in the corresponding frequency band.

[0069] Therefore, in this embodiment, the length along the Y direction from the -Y end of the FM antenna element 500 to the open end E2 of the slit S2 is 1 / 4 of the wavelength λ, but it is acceptable if it is 1 / 4 or less of the wavelength λ. Also, in this embodiment, the length along the Y direction from the open end E3 to the open end E2 is 1 / 4 of the wavelength λ, but it is acceptable if it is 1 / 4 or less of the wavelength λ.

[0070] The GNSS antenna 60 corresponds to the "first antenna," and the FM antenna 50 corresponds to the "second antenna." Furthermore, the Y direction corresponds to the "first direction," the X direction corresponds to the "second direction which is different from the first direction," and the Z direction corresponds to the "third direction which is different from the first and second directions." Slit S1 corresponds to the "first slit," slit S2 corresponds to the "second slit," and slit S3 corresponds to the "third slit."

[0071] <<Regarding the arrangement of the TEL antenna 10 and the GNSS antenna 60>> The TEL antenna 10 in this embodiment transmits and receives radio waves in the 699 MHz to 900 MHz band, for example. The GNSS antenna 60, as described above, receives radio waves in the L1 band (1559 MHz to 1610 MHz band) and the L5 band (1164 MHz to 1214 MHz band), for example. Therefore, the GNSS antenna 60 is compatible with radio waves in frequency bands higher than the 699 MHz to 900 MHz band that the TEL antenna 10 is compatible with.

[0072] Furthermore, the L1 band (1559 MHz to 1610 MHz) of the GNSS antenna 60 is a frequency band that includes harmonics of radio waves in the 699 MHz to 900 MHz band. Note that "harmonics" refer to waves with frequency components that are integer multiples of the fundamental wave, and in this case, the L1 band includes, for example, a frequency component that is twice the frequency of an 800 MHz radio wave. In such cases, the GNSS antenna 60 may be affected by radio waves transmitted from the TEL antenna 10. The frequencies of radio waves that affect the GNSS antenna 60 include not only frequencies that are twice the frequency of the radio waves transmitted from the TEL antenna 10, but also integer multiples of the frequency and frequencies resulting from intermodulation when there are two or more radio waves transmitted from the TEL antenna 10.

[0073] Therefore, in this embodiment, the GNSS antenna 60 and the TEL antenna 10 are arranged on the base 101 so that the GNSS antenna 60 is not affected by radio waves transmitted from the TEL antenna 10. Specifically, the TEL antenna 10 is located at the +Y end in the longitudinal direction of the substantially rectangular base 101, and the GNSS antenna 60 is located at the -Y end in the longitudinal direction of the substantially rectangular base 101. In this way, in this embodiment, the GNSS antenna 60 is positioned as far away from the TEL antenna 10 on the base 101, so that the GNSS antenna 60 is not affected by radio waves transmitted from the TEL antenna 10.

[0074] In this explanation, we have used the TEL antenna 10 and the GNSS antenna 60 as examples, but the explanation is not limited to these. For example, if the frequency band that one of the two antennas corresponds to is higher than the frequency band transmitted by the other antenna, and in particular includes harmonic components of the radio waves transmitted by the other antenna, the same effect as in this embodiment can be obtained by arranging the two antennas as described above.

[0075] For example, the TEL antenna 10 that transmits and receives radio waves in the 699 MHz to 900 MHz band corresponds to the "first antenna corresponding to radio waves in the first frequency band," and the GNSS antenna 60 that corresponds to radio waves in the L1 band corresponds to the "second antenna corresponding to radio waves in the second frequency band."

[0076] Furthermore, the +Y side end of the base 101 in the longitudinal direction corresponds to the "first end," and the -Y side end of the base 101 in the longitudinal direction corresponds to the "second end." In addition, the "end of the base 101" in this embodiment refers not only to the longitudinal end of the base 101, but also to a region that includes a certain range from the end.

[0077] <<Antenna Device 110>> Figure 7 is a plan view of the antenna device 110. The antenna device 110 is similar to the antenna device 100 and consists of a base 101, a cover 102, and multiple antennas (described later). Note that in Figure 7, the cover 102 of the antenna device 110 is omitted for convenience.

[0078] Antenna device 110 is composed of multiple antennas, including a TEL antenna 10, a V2X antenna 20, a DAB (Digital Audio Broadcast) antenna 31, an AM antenna 40, an FM antenna 50, and a GNSS antenna 60. Antenna device 110 has a DAB antenna 31 instead of the SXM antenna 30 of antenna device 100.

[0079] The DAB antenna 31 is, for example, an antenna that corresponds to DAB radio waves in the 174 MHz to 240 MHz band. Here, the DAB antenna 31 is an antenna that corresponds to radio waves for satellite radio broadcasting in the European area, and the SXM antenna 30 is an antenna that corresponds to radio waves for satellite radio broadcasting in the US area, so generally both of these antennas are not mounted on the same vehicle 1. Therefore, for example, in the antenna device 110 for the European area, the DAB antenna 31 is provided instead of the SXM antenna 30.

[0080] By the way, since the AM antenna 40 and FM antenna 50 of this embodiment are connected to the receiver 803 shown in Figure 4, it is necessary to position the FM antenna 50 in close proximity to the AM antenna 40. In other words, there are two possible arrangements: one where the AM antenna 40 is positioned on the +Y side of the FM antenna 50, and another where the AM antenna 40 is positioned on the -Y side of the FM antenna 50. If the AM antenna 40 is positioned on the -Y side of the FM antenna 50, then in Figure 7, the FM antenna 50, not the AM antenna 40, will be positioned next to the DAB antenna 31.

[0081] However, the difference between the center frequency of the DAB antenna 31's frequency band and the center frequency of the FM antenna 50's frequency band (hereinafter referred to as difference D1) is smaller than the difference between the center frequency of the DAB antenna 31's frequency band and the center frequency of the AM antenna 40's frequency band (hereinafter referred to as difference D2). Therefore, if the FM antenna 50 is placed next to the DAB antenna 31, interference may occur between the DAB antenna 31 and the FM antenna 50, potentially degrading the characteristics of each antenna.

[0082] To prevent interference between the two antennas, a filter can be included in one of the antenna circuits, thereby increasing the impedance of the first antenna as seen by the second. However, when the operating frequency bands of the two antennas are extremely close, it is difficult to sufficiently attenuate the radio waves in the operating frequency band of the other antenna with the filter, making it difficult to prevent interference between the two antennas.

[0083] In this embodiment, since the AM antenna 40 is positioned between the DAB antenna 31 and the FM antenna 50, interference between the DAB antenna 31 and the FM antenna 50 can be prevented.

[0084] The AM antenna 40 corresponds to the "first antenna corresponding to radio waves in the first frequency band," the FM antenna 50 corresponds to the "second antenna corresponding to radio waves in the second frequency band," and the DAB antenna 31 corresponds to the "third antenna corresponding to radio waves in the third frequency band." In addition, the cable 812 corresponds to the "cable that transmits the first signal from the first antenna and the second signal from the second antenna."

[0085] <<Antenna Device 120>> Figure 8 is a partial cross-sectional view of the antenna device 120 as seen from the +X direction (rear of the vehicle). In the antenna device 120, the base 201 (described later) is not flat, and a part of the base 201 protrudes in the +Z direction (upward). Also, in the antenna device 120, a part of the upper surface of the cover 202 (described later) that covers the base 201 protrudes in the +Z direction (upward).

[0086] The antenna device 120 has a base 201, a cover 202, and multiple antennas. Since the configuration of the multiple antennas is the same as that described for the antenna device 100, a detailed explanation is omitted here.

[0087] Base 201, like base 101, is a plate-shaped member on which multiple antennas are arranged. Base 201 has an eleventh section 211A, a twelfth section 212A, a twelfth section 211B, and a twelfth section 212B. In base 201, the eleventh section 211A and the twelfth section 211B correspond to the "first section," and the twelfth section 212A and the twelfth section 212B correspond to the "second section."

[0088] The 11th portion 211A and the 12th portion 211B are planar portions that are placed on the bottom surface (i.e., the +Z side surface) of the recess 6 of the vehicle 1. In this embodiment, the 11th portion 211A is located at the +Y side end in the longitudinal direction of the base 201. The TEL antenna 10 is positioned on the upper surface of the 11th portion 211A.

[0089] A convex portion is formed at the -Y side end of the 11th portion 211A, with the +Z side surface designated as the 21st portion 212A. The 21st portion 212A is a planar portion located at a high position above the bottom surface of the recess 6. In this embodiment, a V2X antenna 20 and an SXM antenna 30 are arranged on the upper surface of the 21st portion 212A.

[0090] A recess is formed at the -Y end of the 21st portion 212A, with the bottom surface being the 12th portion 211B. The 12th portion 211B is a planar portion, and an AM antenna 40 and an FM antenna 50 are arranged on its upper surface (the +Z side).

[0091] From the -Y end of the 12th portion 211B, a 22nd portion 212B is formed, which extends to the +Z side and then to the -Y side. The 22nd portion 212B is a planar portion located at a high position above the bottom surface of the recess 6. A GNSS antenna 60 is positioned on the upper surface of the 22nd portion 212B in this embodiment.

[0092] The base 201 of this embodiment has an eleventh portion 211A and a twelfth portion 211B located on the bottom surface of the recess 6, and a 21st portion 212A and a 22nd portion 212B located at a higher position than the eleventh portion 211A and the twelfth portion 211B. Therefore, the V2X antenna 20, SXM antenna 30, and GNSS antenna 60, which are positioned in the 21st portion 212A or the 22nd portion 212B, are raised to a position higher than the bottom surface of the recess 6, making it easier to receive radio waves. As a result, the radio wave reception sensitivity of the V2X antenna 20, SXM antenna 30, and GNSS antenna 60 is improved compared to when they are positioned in the eleventh portion 211A or the twelfth portion 211B.

[0093] Incidentally, a V2X antenna 20 extending in the +Z direction is positioned on the upper surface of the 21st section 212A. Since the V2X antenna 20 is a so-called monopole antenna, it is more preferable that it be positioned above the upper ends of the other antennas. In addition to the monopole antenna, it is also preferable that the dipole antenna be positioned in a similar location.

[0094] In particular, the V2X antenna 20 is an antenna for autonomous driving that requires a small gain deviation in the horizontal plane. For this reason, it is preferable that the V2X antenna 20 is positioned above the upper ends of the other antennas. Therefore, in this embodiment, the shape of the cover 202 and a part of the roof panel 4 is changed to improve the antenna gain of the V2X antenna 20. The details of the cover 202 and the roof panel 4 will be described below.

[0095] The cover 202 is a component that, together with the base 201, forms a housing space for accommodating multiple antennas. The cover 202 is a box-shaped component with an opening on the -Z side, and has an upper surface portion 221, a protruding portion 222, and a side wall portion 223.

[0096] The upper portion 221 is a member that covers the top of multiple antennas. In plan view, the upper portion 221 is a roughly rectangular plate-like member, but in this embodiment, the upper portion 221 has a projection 222 (described later) that can accommodate the +Z side end of the V2X antenna 20.

[0097] Furthermore, the cover 202 has side wall portions 223 extending in the -Z direction from each end on the X side and each end on the Y side of the upper surface portion 221. In this embodiment, the side wall portions 223 are formed such that the housing space is substantially sealed when the cover 202 covers the base 201.

[0098] The protruding portion 222 is a part that protrudes upward from the upper surface portion 221. In a plan view, the protruding portion 222 is provided near the part of the upper surface portion 221 where the V2X antenna 20 is positioned. A housing space SP is formed inside the protruding portion 222. The housing space SP houses the part of the V2X antenna 20 that protrudes in the Z direction more than the other antennas (i.e., the +Z side end of the V2X antenna 20).

[0099] The upper portion 221 corresponds to the "first part," and the protruding portion 222 corresponds to the "second part."

[0100] In this embodiment, since the protrusion 222 protrudes above the upper surface portion 221, the roof panel 4 of the vehicle 1 has a roof protrusion 4P that matches the shape of the protrusion 222. The protrusion 222 and a part of the V2X antenna 20 are positioned on the vehicle interior side of the roof protrusion 4P.

[0101] The roof panel 4 does not necessarily have to have a roof projection 4P. In this case, a hole (not shown) may be formed in the roof panel 4, and the projection 222 may protrude from the hole in the roof panel 4 from the interior side of the vehicle 1 to the exterior side of the vehicle 1. In this case, the gap between the hole in the roof panel 4 and the projection 222 may be filled with resin or the like.

[0102] Alternatively, the antenna device 120 may be positioned at a location shifted downward in the Z direction so that the protruding portion 222 of the antenna device 120 does not come into contact with the roof panel 4.

[0103] As described above, the antenna device 120 of this embodiment has a cover 202 with a protrusion 222, and the V2X antenna 20 is housed in the housing space SP of the protrusion 222. Therefore, the V2X antenna 20 is less susceptible to the influence of multiple other antennas, and thus the antenna gain and directivity of the V2X antenna 20 can be improved.

[0104] In this embodiment, the antenna device 120 had a base 201 having an eleventh portion 211A and a twelfth portion 211B, and a twelfth portion 212A and a twelfth portion 212B, and a cover 202 having a protrusion 222. However, the antenna device 120 may have only one of the features of the base 201 or the features of the cover 202.

[0105] Furthermore, the V2X antenna 20 in this embodiment corresponds to an "antenna extending along a third direction," and the SXM antenna 30 corresponds to a "planar antenna positioned at the second location."

[0106] <<Antenna Device 130>> The antenna device 130 shown in Figure 9 is provided with a cylindrical wall portion 131 surrounding the V2X antenna 20, in addition to the configuration of the antenna device 100 of the first embodiment. Note that the antenna device 130 includes the wall portion 131 in addition to the configuration of the antenna device 100 described above, but for convenience, the V2X antenna 20, the wall portion 131, and a part of the frame 5 are shown in this illustration.

[0107] The wall portion 131 is a metal wall member that surrounds the V2X antenna 20, but it may also be a member made of resin with a conductive film attached to its surface, for example. The wall portion 131 is cylindrical, and the V2X antenna 20 is positioned at the geometric center of the wall portion 131 in a top view. The radius R of the wall portion 131 is at least half the wavelength of the corresponding frequency of the V2X antenna 20. In this embodiment, the corresponding frequency of the V2X antenna 20 is 5.9 GHz, and the wavelength of this frequency is about 50 mm. Therefore, the radius R is about 25 mm or more. The wall portion 131 extends from the base 101 in the +Z direction. Note that the wall portion 131 may have a cutout in part of it, and may not completely surround the V2X antenna 20, but may surround the V2X antenna 20 only in a desired direction.

[0108] Figure 10 shows the simulation results of the horizontal directivity of the V2X antenna 20. The numbers around the graph in Figure 10 indicate the azimuth in the horizontal plane (unit: °). The numbers from the center of the graph in Figure 10 to azimuth 0° indicate the gain (unit: dBi). In the graph in Figure 10, azimuth 0° is the +X direction (forward direction). Azimuth 90° is the -Y direction (right direction). Azimuth 180° is the -X direction (backward direction). Azimuth 270° is the +Y direction (left direction).

[0109] In the graph shown in Figure 10, the dashed line represents the gain when there is no wall portion 131, the solid line represents the gain when there is a wall portion 131 with a diameter of 50 mm, and the dashed line represents the gain when there is a wall portion 131 with a diameter of 300 mm.

[0110] In the absence of the wall portion 131 in the antenna device 130, the horizontal directivity of the V2X antenna 20 is affected by the shape of the recess 6 in which the antenna device 130 is housed. Specifically, the radio waves transmitted from the V2X antenna 20 are scattered by the frame 5 that forms the recess 6, causing a phase shift in the radio waves. As these phase-shifted radio waves are combined, the horizontal directivity of the V2X antenna 20 in the absence of the wall portion 131 exhibits a large gain deviation.

[0111] On the other hand, if the wall portion 131 is located inside the frame 5 that forms the recess 6 in the antenna device 130, the horizontal directivity of the V2X antenna 20 is affected by the cylindrical wall portion 131. For this reason, when the radius R of the wall portion 131 is 25 mm (diameter 50 mm), the horizontal directivity of the V2X antenna 20 shows a smaller gain deviation compared to the case where there is no wall portion 131 (the pie chart shows smaller irregularities). Furthermore, when the radius R of the wall portion 131 is 150 mm (diameter 300 mm), the gain deviation is even smaller compared to the case where the radius R of the wall portion 131 is 25 mm.

[0112] In this embodiment, the antenna device 130 has a cylindrical wall portion 131 provided at a distance of at least half the wavelength of the corresponding frequency of the V2X antenna 20. Since the radio waves transmitted from the V2X antenna 20 are reflected by the cylindrical wall portion 131 which is at the same distance from the V2X antenna 20, the phase of the radio waves is less likely to shift. As a result, the reflected radio waves with small phase shifts are combined, which improves the antenna gain and directivity of the V2X antenna 20.

[0113] In this embodiment, the V2X antenna 20 corresponds to an "antenna extending along a third direction."

[0114] <<Antenna Device 140>> The antenna device 140 shown in Figure 11 has a slot 5S provided in a frame 5 that is positioned away from the V2X antenna 20, compared to the antenna device 100 of the first embodiment. The antenna device 140 includes the configuration of the antenna device 100 described above, but for convenience, the V2X antenna 20 and a part of the frame 5 (the bottom surface of the recess 6 and the surface in the X direction) are shown here.

[0115] The antenna device 140 is located inside the recess 6, similar to the antenna device 100 shown in Figures 1 and 2. Therefore, the antenna device 140 is located on the -X side or +X side of the recess 6 and is spaced apart from the frame 5 that extends in the +Z direction. The antenna device 140 may be located in a place other than the recess 6, where a total of four sides in the X and Y directions are enclosed by the frame 5. For example, the antenna device 140 may be located in a place where wall members are provided on only two sides in the X direction or only two sides in the Y direction.

[0116] Slot 5S is a rectangular opening formed in the metal frame 5. Slot 5S does not have to be rectangular; it may be a square, polygonal, or circular opening. Slot 5S penetrates the frame 5 in the X direction. Slot 5S is located on the -X side of the recess 6 and is formed in the frame 5 extending in the +Z direction. The length of slot 5S in the Y direction (longitudinal length) is half the wavelength of the corresponding frequency of the V2X antenna 20. In this embodiment, the corresponding frequency of the V2X antenna 20 is 5.9 GHz, and the wavelength of this frequency is approximately 50 mm. Therefore, the length of slot 5S in the Y direction is approximately 25 mm.

[0117] In the antenna device 140 shown in Figure 11, one slot 5S is provided on the frame 5 on the -X side, but multiple slots 5S may be provided on the frame 5 on the -X side. Also, slots 5S may be provided not only on the frame 5 on the -X side, but also on other frames 5 that constitute the side surface of the recess 6. Furthermore, slots 5S may be provided on frames 5 parallel to the XY plane.

[0118] Figure 12 shows the simulation results of the horizontal directivity of the V2X antenna 20. The numbers around the graph in Figure 12 indicate the azimuth (in degrees Celsius) in the horizontal plane. The numbers from the center of the graph in Figure 12 to azimuth 0° indicate the gain (in dBi). In the graph in Figure 12, azimuth 0° is the +X direction (forward direction). Azimuth 90° is the -Y direction (right direction). Azimuth 180° is the -X direction (backward direction). Azimuth 270° is the +Y direction (left direction).

[0119] In the graph shown in Figure 12, the dashed line shows the gain when there is no slot 5S in frame 5, and the solid line shows the gain when there is a slot 5S in frame 5.

[0120] Slot 5S is positioned at a 180° angle to the V2X antenna 20. Since the antenna device 140 is located in the recess 6, the radio waves radiated from the V2X antenna 20 are blocked by the frame 5 and have difficulty leaving the recess 6.

[0121] On the other hand, if frame 5 has a slot 5S, the radio waves radiated from the V2X antenna 20 are more likely to pass through the slot 5S and exit the recess 6. Therefore, compared to the case where frame 5 does not have a slot 5S in the antenna device 140, the gain in the direction of the slot 5S (180° relative to the V2X antenna 20) is improved when frame 5 has a slot 5S.

[0122] In this embodiment, the V2X antenna 20 corresponds to an "antenna extending along the third direction," and the frame 5 corresponds to a "conductive wall."

[0123] <<Antenna Device 150>> The antenna device 150 shown in Figure 13 differs from the antenna device 100 of the first embodiment in that the V2X antenna 151 is provided on the outer surface of the frame 5. The antenna device 150 includes the configuration of the antenna device 100 described above, but for convenience, only the V2X antenna 151 and a part of the frame 5 (the bottom surface of the recess 6 and the surface in the X direction) are shown here. The V2X antenna 151 is formed as a loop antenna, but it may be formed in other antenna types.

[0124] The antenna device 150 has the same configuration as the base 101 of the antenna device 100 shown in Figures 1 and 2. Therefore, the base 101 of the antenna device 150 is located on the -X side or +X side of the recess 6 and is spaced apart from the frame 5 that extends in the +Z direction. The antenna device 150 may be placed in a location other than the recess 6, where a total of four surfaces in the X and Y directions are enclosed by the frame 5. For example, the antenna device 150 may be placed in a location where wall members are provided on only two surfaces in the X direction or only two surfaces in the Y direction.

[0125] Figure 14 shows the simulation results of the horizontal directivity of V2X antennas 20 and 151. The numbers around the graph in Figure 14 indicate the azimuth (in degrees) in the horizontal plane. The numbers from the center of the graph in Figure 14 to azimuth 0° indicate the gain (in dBi). In the graph in Figure 14, azimuth 0° is the +X direction (forward direction). Azimuth 90° is the -Y direction (right direction). Azimuth 180° is the -X direction (backward direction). Azimuth 270° is the +Y direction (left direction).

[0126] In the graph shown in Figure 14, the dashed line represents the gain of the V2X antenna 20 located inside the recess 6, and the solid line represents the gain of the V2X antenna 151 located outside the recess 6.

[0127] The V2X antenna 20, which is positioned inside the recess 6, is affected by the shape of the recess 6 in which the V2X antenna 20 is housed. As a result, the horizontal directivity of the V2X antenna 20 exhibits a large gain deviation.

[0128] On the other hand, in the antenna device 150, when the V2X antenna 151 is positioned on the outer surface of the frame 5 that forms the recess 6, the V2X antenna 151 is less affected by the frame 5. Therefore, the horizontal directivity of the V2X antenna 151 shows a smaller gain deviation compared to the V2X antenna 20 positioned inside the recess 6 (the pie chart shows smaller peaks and valleys).

[0129] In this embodiment, the V2X antenna 151 corresponds to an "antenna extending along a third direction," and the frame 5 corresponds to a "conductive wall."

[0130] <<Antenna Device 160>> The antenna device 160 shown in Figure 15 has two V2X antennas 20A and 20B compared to the antenna device 100 of the first embodiment. The antenna device 160 is placed in a recess 6 which is inside a conductive frame 161 and is surrounded by the frame 161. The antenna device 160 includes the configuration of the antenna device 100 described above, but for convenience, the V2X antennas 20A and 20B and the frame 161 that forms the recess 6 are shown here. In addition, although the antenna device 160 is surrounded by the frame 161 in a rectangular shape, the frame 161 does not have to be rectangular and may be circular.

[0131] The V2X antennas 20A and 20B employ a diversity system. In the diversity system, when receiving signals with the two V2X antennas 20A and 20B, the signal with the larger gain is selected. The overall directivity of the two V2X antennas 20A and 20B is determined by superimposing the directivity of each individual antenna, and only the maximum gain is selected.

[0132] The V2X antennas 20A and 20B are positioned inside frame 5, separated by an antenna distance D. The antenna distance D is the shortest straight-line distance between the two V2X antennas 20A and 20B.

[0133] Figure 16 shows the simulation results of the horizontal directivity of V2X antennas 20A and 20B. The numbers around the graph in Figure 16 indicate the azimuth in the horizontal plane (unit: °). The numbers from the center of the graph in Figure 16 to azimuth 0° indicate the gain (unit: dBi). In the graph in Figure 16, azimuth 0° is the +X direction (forward direction). Azimuth 90° is the -Y direction (right direction). Azimuth 180° is the -X direction (backward direction). Azimuth 270° is the +Y direction (left direction).

[0134] In the graph shown in Figure 16, the dashed line represents the gain of the V2X antenna 20A, and the solid line represents the gain of the V2X antenna 20B.

[0135] As described above, the V2X antennas 20A and 20B employ a diversity system, so the directivity of each antenna is superimposed, and only the maximum gain is selected. Here, the maximum gain when the directivity of each antenna is superimposed is called the composite value. The performance of the V2X antennas 20A and 20B is better the larger the minimum value of this composite value.

[0136] Incidentally, in the V2X antennas 20A and 20B positioned inside the recess 6, the performance is thought to change depending on the magnitude of the distance D between the antennas. The following describes the simulation results that led to the calculation of a preferred range of values ​​for the distance D between the antennas.

[0137] In this simulation, as an example of a recess 6, we assumed a recess 6 in which the length of the frame 161 in the X direction and the length of the frame 161 in the Y direction are both 200 mm. Then, we prepared 1500 data points in which two V2X antennas 20A and 20B were randomly placed apart inside the frame 5, and calculated the distance D between the antennas for each of the 1500 data points. Furthermore, for the 1500 data points, we calculated the composite value, which is the maximum gain when the directivity of each antenna is superimposed, through simulation.

[0138] Next, the minimum composite value was calculated for 1500 data points. Then, only the data where the minimum composite value was -7 dB or higher was extracted from the 1500 data points. Here, the extracted data is referred to as the extracted data. As mentioned above, a larger minimum composite value indicates better antenna performance, so the extracted data is considered to be data with good antenna performance.

[0139] Next, for the 1500 data points, the number of data points corresponding to each 10 mm interval for antenna distance D from 0 mm to 290 mm was counted. Then, for the extracted data, the number of data points corresponding to each 10 mm interval for antenna distance D from 0 mm to 290 mm was counted. Finally, for each 10 mm interval, the number of data points corresponding to the extracted data was divided by the number of data points corresponding to the 1500 data points to calculate the ratio. The calculated ratio is the proportion of data points for which the minimum composite value is -7 dB or greater relative to the number of data points corresponding to each range of antenna distance D. In other words, the larger this ratio, the better the antenna performance is considered to be for the antenna distance D.

[0140] The graph in Figure 17 shows the antenna distance D in 10 mm increments on the horizontal axis and the calculated percentage on the vertical axis. From the graph in Figure 17, it can be seen that antenna distances D with a large percentage are concentrated in the range of 90 mm to 160 mm. As mentioned above, the larger the percentage shown on the vertical axis of the graph, the better the antenna performance is considered to be for the antenna distance D. Therefore, when the antenna distance D is between 90 mm and 160 mm, the antenna performance of V2X antennas 20A and 20B is considered to be good.

[0141] Here, the corresponding frequency for V2X antennas 20A and 20B is 5.9 GHz, and the wavelength of this frequency is approximately 50 mm. In this case, 90 mm is 1.8 times the wavelength of the corresponding frequency for V2X antennas 20A and 20B. Also, 160 mm is 3.2 times the wavelength of the corresponding frequency for V2X antennas 20A and 20B. From the above, it can be concluded that the preferred range for the distance D between antennas is 1.8 to 3.2 times the wavelength of the corresponding frequency for V2X antennas 20A and 20B.

[0142] In this embodiment, the V2X antenna 20A corresponds to the "fourth antenna," and the V2X antenna 20B corresponds to the "fifth antenna." Also, the frame 161 corresponds to the "conductive wall."

[0143] <<Antenna Device 300>> Figure 18 is a perspective view showing a part of the antenna device 300. Figure 19 is a cross-sectional view taken along line A-A in Figure 18. The antenna device 300 consists of a V2X antenna 20, a base 101, a substrate 103, and a wall portion 131. The antenna device 300 is arranged on, for example, a frame 5. However, it is not limited to this, and the antenna device 300 may be arranged on the roof of the vehicle or inside a spoiler. The antenna device 300 differs from the antenna device 130 shown in Figure 9 in the following respects.

[0144] In the antenna device 300, the base 101 has, for example, a circular first opening 104 in plan view. However, the shape of the opening 104 in plan view is not limited to a circle, but may be elliptical, polygonal, or a combination thereof. The wall portion 131 is provided on the +Z-direction side surface of the base 101 along the edge of the first opening 104. The wall portion 131 extends from the +Z-direction side surface of the base 101 toward the +Z direction. A substrate 103 is attached to the -Z-direction side surface of the base 101. The V2X antenna 20 is positioned on the +Z-direction side surface of the substrate 103. The V2X antenna 20 is positioned at the geometric center of the first opening 104 and the wall portion 131 in plan view.

[0145] The substrate 103 is a plate-shaped member on which conductor patterns and electronic components such as antenna impedance matching circuits and amplification circuits are arranged. In this embodiment, the substrate 103 is, for example, a printed circuit board (PCB), formed from a resin material such as glass epoxy resin, on which conductor patterns and electronic components are arranged. However, although the substrate 103 is a rigid substrate, it is not limited to this, and may be a flexible substrate or a rigid-flexible substrate. The substrate 103 has a power supply section 105.

[0146] The power supply section 105 is a part that includes a power supply point where the power supply line (not shown) of the antenna device 300 is electrically connected to the V2X antenna 20 and a ground section (not shown) provided on the circuit board 103. The power supply section 105 includes a part where the inner conductor (not shown) of the power supply line of the antenna device 300 is connected to the V2X antenna 20, and a part where the outer conductor (not shown) of the power supply line of the antenna device 300 is connected to the ground section.

[0147] Alternatively, instead of a power supply line connected to the power supply unit 105, a conductor pattern may be provided on the substrate 103. In this case, the conductor pattern will be connected to the V2X antenna 20 and the ground (not shown). Furthermore, the power supply unit 105 may be located outside the first opening 104 in a plan view. In this case, the V2X antenna 20 and the power supply unit 105 will be connected, for example, by a conductor pattern drawn on the substrate 103.

[0148] Furthermore, the radius R of the wall portion 131, that is, the distance between the V2X antenna 20 and the wall portion 131, is preferably at least 1 / 8 of the wavelength of the corresponding frequency of the V2X antenna 20. Generally, if the distance between the wall portion and the antenna is excessively close, the current distribution flowing through the antenna may be disturbed, potentially reducing the radiation efficiency. Therefore, in this embodiment, by setting the distance between the V2X antenna 20 and the wall portion 131 to at least 1 / 8 of the wavelength of the corresponding frequency of the V2X antenna 20, the radiation characteristics of the V2X antenna 20 can be ensured while effectively utilizing the influence of the wall portion 131.

[0149] Furthermore, the length of the wall portion 131 in the +Z direction is preferably 1 / 8 or more of the wavelength of the corresponding frequency of the V2X antenna 20. Generally, if the height of the wall portion is excessively low, the electromagnetic field may wrap around the upper end of the wall portion, and the electromagnetic field control effect of the wall portion may not be sufficiently obtained. Therefore, in this embodiment, by setting the height of the wall portion 131 to 1 / 8 or more of the wavelength of the corresponding frequency of the V2X antenna 20, the wall portion 131 can effectively act on the electromagnetic field, and the electromagnetic field distribution near the V2X antenna 20 can be appropriately controlled.

[0150] Furthermore, it is preferable that the base 101 has a length of at least half the wavelength of the corresponding frequency of the V2X antenna 20 in the radial direction centered on the V2X antenna 20, extending outward from the wall portion 131. Generally, if the length of the base extending outward from the wall portion is excessively short, the influence of the outer edge of the wall portion becomes dominant, and the electromagnetic field control effect by the wall portion may become spatially non-uniform. Therefore, in this embodiment, the length of the base 101 extending outward from the wall portion 131 is set to at least half the wavelength of the corresponding frequency of the V2X antenna 20, thereby reducing the influence of the edge of the wall portion 131 and ensuring that the wall portion 131 acts stably on the electromagnetic field.

[0151] The base 101 may also be a conductive pattern arranged on a substrate 103 that has the same shape as the base 101 in a plan view.

[0152] The antenna device 300 of this embodiment has, for example, a cylindrical wall portion 131 surrounding the V2X antenna 20, and a base 101 extending outward from the wall portion 131. However, the wall portion 131 is not limited to a cylindrical shape; it may be an elliptical cylinder or a polygonal cylinder, as long as it follows the edge of the first opening 104. Even with such a configuration, the antenna device 300 can obtain the same gain as shown in the graph with the wall portion 131 in Figure 10. That is, the antenna device 300 can improve the horizontal gain of the V2X antenna 20 while suppressing the effect of nulls, similar to the antenna device 130 shown in Figure 9.

[0153] Figure 20 shows an example of an antenna device 300A, which is a modified version of the antenna device 300. The antenna device 300A consists of a V2X antenna 20, a base 101, a substrate 103, and a wall section 131. Here, the base 101 and the wall section 131 differ from those of the antenna device 300, so the explanation will focus on the base 101 and the wall section 131.

[0154] As shown in Figure 20, in the antenna device 300A, the base 101 is located away from the substrate 103 in the +Z direction. In this case, the wall portion 131 extends in the +Z direction from the surface of the substrate 103 on the +Z side. The base 101 extends radially outward from the upper end of the wall portion 131.

[0155] The wall portion 131 and the base 101 may be structures with other functions. For example, the wall portion 131 and the base 101 may be part of a heat sink that has the function of cooling electronic components mounted on the substrate 103.

[0156] In the configuration shown in Figure 19, the overall height of the antenna device can be reduced by fixing the wall portion 131 and the base 101 supporting the V2X antenna 20 to the housing side. On the other hand, in the configuration shown in Figure 20, a space is formed between the base 101 and the bottom surface of the housing. For example, electronic components mounted on the circuit board 103 can be placed in this space, making effective use of the space inside the housing. Furthermore, since the base 101 and the wall portion 131 are interposed between the electronic components and the V2X antenna 20, electromagnetic noise generated from the electronic components can be suppressed from coupling to the V2X antenna 20, and the impact on antenna characteristics can be reduced even if the arrangement or configuration of the electronic components is changed.

[0157] Even with such an antenna device 300A, it is possible to improve the horizontal gain of the V2X antenna 20 while suppressing the effects of nulls, similar to the antenna device 300.

[0158] <<Antenna Device 310>> Figure 21 is an explanatory diagram of the antenna device 310. Figure 22 is a cross-sectional view taken along line B-B of Figure 21. The antenna device 310 consists of a V2X antenna 20, a base 101, a substrate 103, a wall portion 131, and a reflector 311. The antenna device 310 differs from the antenna device 300 in that it has a reflector 311.

[0159] The reflector 311 is a conductor that acts as a reflector for the V2X antenna 20. In this embodiment, the reflector 311 is provided on the surface of the substrate 103 on the +Z side in a region radially inward of the wall portion 131 in a plan view. The reflector 311 may or may not be electrically connected to the base 101 and the wall portion 131.

[0160] The antenna device 310 can change the directivity of the V2X antenna 20 by changing the size of the reflector 311 and the distance from the V2X antenna 20 to the reflector 311. Therefore, the antenna device 310 can achieve the same effect as the antenna device 300, while also improving the directivity characteristics and nulls of the V2X antenna 20.

[0161] Figure 23 shows an example of an antenna device 310A, which is a modified version of the antenna device 310. The antenna device 310A consists of a V2X antenna 20, a base 101, a substrate 103, a wall section 131A, and a reflector 311. Here, the wall section 131A and the reflector 311 differ from those of the antenna device 310, so the explanation will focus on the wall section 131A and the reflector 311.

[0162] As shown in Figure 23, in the antenna device 310A, a wall portion 131A having an opening is provided in place of the wall portion 131. In this case, the reflector 311 may be provided on the front surface of the substrate 103 so as to close the opening of the wall portion 131A, or it may be provided on the surface of the base 101 on the +Z direction side. Furthermore, the reflector 311 may be a separate component from the wall portion 131A or the base 101, or it may be an integral component with the wall portion 131A or the base 101. The reflector 311 may be provided away from the wall portion 131A, or it may be provided so as to be in contact with the wall portion 131.

[0163] In this invention, the wall portion is positioned near the antenna to act on the radio waves radiated from the antenna, and is configured to homogenize the re-radiated component due to the surface current induced in the wall portion in the circumferential direction. This reduces the distance difference and phase difference between radiated components, and suppresses the occurrence of nulls caused by the cancellation of radiated components with different phases. In other words, the wall portion is a component that prevents abrupt drops in radiation characteristics by regulating the electromagnetic field distribution near the antenna.

[0164] In contrast, a reflector is a component that acts on electromagnetic waves radiated from an antenna, reflecting those electromagnetic waves to enhance radiation in a desired direction and create directivity. Reflectors utilize the phase relationship of the electromagnetic waves after radiation to form radiation characteristics, and do not suppress the phase variation of the current distribution or re-radiated components near the antenna.

[0165] In this embodiment, the wall sections 131, 131A and the reflector 311, which have different targets and technical roles, are arranged near the V2X antenna 20. The configuration stabilizes the electromagnetic field distribution near the V2X antenna 20 with the wall sections 131, 131A, and then controls the electromagnetic waves after radiation with the reflector 311. This makes it possible to achieve both null suppression and directivity formation, and to comprehensively improve the antenna characteristics.

[0166] Even with such an antenna device 310A, it is possible to improve the directional characteristics and nulls of the V2X antenna 20, just as with the antenna device 310.

[0167] <<Antenna Device 320>> Figure 24 is an explanatory diagram of the antenna device 320. The antenna device 320 consists of a V2X antenna 20, a base 101, a substrate 103, and a wall portion 131. The antenna device 320 differs from the antenna device 300 in that the base 101 has a second opening 321.

[0168] The second opening 321 is a through hole that penetrates the base 101 in the Z direction. In this embodiment, the second opening 321 is provided in the base 101 at a location away from the first opening 104. The second opening 321 is, for example, an air vent or a hole intended to avoid interference with fastening components or surrounding structures. The maximum opening length d of the second opening 321 is smaller than the maximum opening length 2R of the first opening 104. The opening shape of the second opening 321 may be circular, elliptical, polygonal, or a combination thereof.

[0169] In the antenna device 320 shown in Figure 24, two second apertures 321 are provided on the base 101. The two second apertures 321 are identical in shape. However, if multiple second apertures 321 are provided on the base 101, their shapes and sizes do not need to be identical.

[0170] Generally, if the length of the opening (hole) provided in the base is 1 / 4 or more of the wavelength of the corresponding frequency of the antenna, the opening itself is more likely to act resonantly, which may unnecessarily affect the radiation characteristics of the antenna. For this reason, in this embodiment, in the antenna device 320, the maximum opening length d of the second opening 321 is preferably less than 1 / 4 of the wavelength of the corresponding frequency of the V2X antenna 20.

[0171] Furthermore, when multiple openings (holes) are provided in the base, if the distance between the openings is less than 1 / 16 of the wavelength of the corresponding frequency of the antenna, electromagnetic coupling between adjacent openings will become stronger, which may easily lead to localized current concentration and disturbances in the electromagnetic field distribution. For this reason, in this embodiment, the distance L2 between the two second openings 321 provided in the base 101 is preferably 1 / 16 or more of the wavelength of the corresponding frequency of the V2X antenna 20. With this configuration, the influence of the second openings 321 on the radiation characteristics of the V2X antenna 20 can be suppressed.

[0172] Therefore, the antenna device 320 not only improves the directivity characteristics and null of the V2X antenna 20, similar to the antenna device 300, but also suppresses the influence of the second aperture 321 on the radiation characteristics of the V2X antenna 20.

[0173] <<Antenna Device 330>> Figure 25 is an explanatory diagram of the antenna device 330. Figure 26 is a cross-sectional view taken along line C-C of Figure 25. The antenna device 330 consists of a planar antenna 331, a base 101, a substrate 103, and a wall portion 131B. The antenna device 330 differs from the antenna device 300A shown in Figure 20 in the following respects.

[0174] The antenna device 330 has a planar antenna 331 instead of the V2X antenna 20. In plan view, the shape of the wall portion 131B is modified to conform to the side shape of the planar antenna 331. In the antenna device 330 shown in Figure 25, since the side shape of the planar antenna 331 is rectangular, the shape of the wall portion 131B is also rectangular. In plan view, the planar antenna 331 is positioned on the +Z side surface of the substrate 103 so as to be located at the geometric center of the wall portion 131B.

[0175] Next, the planar antenna 331 will be described. The planar antenna 331 is a planar antenna such as an SXM antenna 30 or a GNSS antenna 60. The planar antenna 331 includes a radiating element 332 and a dielectric member 333.

[0176] The radiating element 332 is a conductive member formed to correspond to, for example, SXM or GNSS radio waves. In this embodiment, the radiating element 332 is placed on the +Z-direction side surface of the dielectric member 333 and is formed in a substantially quadrilateral shape smaller than the size of the +Z-direction side surface of the dielectric member 333. The radiating element 332 has a feeding section (not shown). The feeding section is a part that includes a feeding point where the feed line of the planar antenna 331 is electrically connected to the radiating element 332.

[0177] The dielectric member 333 is a substantially rectangular parallelepiped made of a dielectric material such as ceramic. The dielectric member 333 is positioned on the +Z direction side of the substrate 103. A ground portion (not shown) is formed as a conductive pattern on the -Z direction side of the dielectric member 333. The ground portion may be provided as a separate plate-shaped or film-shaped member from the dielectric member 333.

[0178] The antenna device 330 is provided with a wall portion 131B and a base 101 surrounding the planar antenna 331. Here, the base 101 extending from the wall portion 131B outward from the outer circumference of the wall portion 131B functions as the ground portion of the planar antenna 331, increasing the electrical length of the ground portion of the planar antenna 331. As a result, the gain and axial ratio of the planar antenna 331 are improved compared to the case where there is no wall portion 131B and no base 101 extending outward from the wall portion 131B.

[0179] Figure 27 shows an example of an antenna device 330A, which is a modified version of the antenna device 330. The antenna device 330A consists of a planar antenna 331A, a base 101, a substrate 103, and a wall section 131C. Here, since the planar antenna 331A and the wall section 131C differ from those of the antenna device 330, the explanation will focus on the planar antenna 331A and the wall section 131C.

[0180] As shown in Figure 27, the planar antenna 331A includes a radiating element 332A and a dielectric member 333A.

[0181] The radiating element 332A is positioned on the +Z-direction side of the dielectric member 333A and is formed in a substantially circular shape smaller than the size of the +Z-direction side of the dielectric member 333A. Other features of the radiating element 332A are the same as those of the radiating element 332, so a detailed explanation is omitted here.

[0182] The dielectric member 333A is a substantially cylindrical member. Since the other characteristics of the dielectric member 333A are the same as those of the dielectric member 333, a detailed explanation is omitted here.

[0183] As shown in Figure 27, in the antenna device 330A, the side shape of the planar antenna 331A is circular in plan view. Therefore, in plan view, the shape of the wall portion 131C is changed to a circular shape to match the side shape of the planar antenna 331A.

[0184] Even with such an antenna device 330A, it is possible to achieve the same effect as with antenna device 330 in improving the gain and axial ratio of the planar antenna 331A.

[0185] <<Antenna Device 340>> Figure 28(a) is an explanatory diagram of the antenna device 340. The antenna device 340 consists of a V2X antenna 20, a base 101, a substrate 103, wall sections 131D and 131E, and an inverted L-shaped antenna 350. The antenna device 340 differs from the antenna device 300A shown in Figure 20 in that the wall sections 131D and 131E and the base 101 surround only a part of the V2X antenna 20, and the base 101 and wall section 131E function as antenna elements of the inverted L-shaped antenna 350.

[0186] The wall portions 131D and 131E are plate-shaped members extending in the Y direction. The wall portions 131D and 131E extend from the surface of the substrate 103 on the +Z direction side in the +Z direction and parallel to the Y direction. In this embodiment, the wall portions 131D and 131E are provided opposite each other in the X direction with the V2X antenna 20 as the center. Note that the number of wall portions provided in the antenna device 340 is not limited to two.

[0187] The base 101 extends in the X direction from the upper end of the wall portion 131D. In this embodiment, the base 101 extends in the -X direction from the upper end of the wall portion 131D and in the +X direction from the upper end of the wall portion 131E.

[0188] The inverted L-shaped antenna 350 is an antenna that corresponds to a different frequency band than the V2X antenna 20. In this embodiment, the inverted L-shaped antenna 350 is composed of a base 101, a wall portion 131E, and a feed point 351. In the inverted L-shaped antenna 350, the base 101 and the wall portion 131E function as antenna elements of the inverted L-shaped antenna 350, so the feed point 351 will be described here.

[0189] The power supply section 351 is a portion that includes a power supply point where the power supply line (not shown) of the inverted L-shaped antenna 350 is electrically connected to the wall portion 131E and the ground portion (not shown) provided on the substrate 103. The power supply section 351 includes a portion where the inner conductor (not shown) of the power supply line of the inverted L-shaped antenna 350 is connected to the wall portion 131E, and a portion where the outer conductor (not shown) of the power supply line of the inverted L-shaped antenna 350 is connected to the ground portion.

[0190] In this embodiment, the antenna device 340 utilizes a portion of the base 101 as an antenna. The base 101 and the wall portion 131D are components that constitute the housing structure and are mechanically fixed in a stable manner, making them less susceptible to vibration and assembly variations. Therefore, it is possible to suppress fluctuations in antenna characteristics due to vibrations during operation and aging.

[0191] Unlike antenna devices 300 and 300A, antenna device 340 has a configuration in which a portion of the V2X antenna 20 is enclosed by the wall portion 131E and base 101 of the inverted L-shaped antenna 350. For this reason, in antenna device 340, for example, the V2X antenna 20 is partially enclosed compared to antenna device 300. However, even with such an antenna device 340, the directivity of the V2X antenna 20 can be improved, similar to antenna device 300, compared to antenna device 340 without the inverted L-shaped antenna 350.

[0192] Furthermore, since the antenna device 340 utilizes the wall portion 131E and the base 101 as antenna elements of the inverted L-shaped antenna 350, the number of antennas mounted on the antenna device 340 can be increased without increasing the size of the antenna device 340.

[0193] Figure 28(b) shows an example of antenna device 340A, which is a modified version of antenna device 340. Antenna device 340A consists of a V2X antenna 20, a base 101, a substrate 103, wall sections 131D and 131F, and an inverted F antenna 360. Here, the inverted F antenna 360 is different from that of antenna device 340, so the explanation will focus on the inverted F antenna 360.

[0194] The inverted F-type antenna 360 is an antenna that corresponds to a different frequency band than the V2X antenna 20. In this embodiment, the inverted F-type antenna 360 is composed of a base 101, a wall section 131F, a feed section 361, and a plate-shaped element 362. Note that the wall section 131F is not connected to the feed section relative to the wall section 131E, but is provided on the substrate 103. In the inverted F-type antenna 360, the base 101 and the wall section 131F function as antenna elements of the inverted F-type antenna 360, so here we will describe the feed section 361 and the plate-shaped element 362.

[0195] The feeding section 361 is a part that includes a feeding point where the feed line (not shown) of the inverted F-type antenna 360 is electrically connected to the plate-shaped element 362 and a ground section (not shown) provided on the substrate 103. The feeding section 361 includes a part where the inner conductor (not shown) of the feed line of the inverted F-type antenna 360 is connected to the plate-shaped element 362, and a part where the outer conductor (not shown) of the feed line of the inverted F-type antenna 360 is connected to the ground section.

[0196] The plate-shaped element 362 is made of a conductor such as metal. The plate-shaped element 362 is provided on the surface of the substrate 103 on the +Z direction side and further on the +X direction side than the wall portion 131F. The upper end of the plate-shaped element 362 is electrically connected to the base 101. Therefore, the base 101 and the wall portion 131F are supplied with power through the plate-shaped element 362.

[0197] In this embodiment, the antenna device 340A employs a configuration in which a portion of the antenna element of the inverted F antenna 360 is short-circuited, thereby allowing the impedance characteristics in a desired frequency band to be adjusted. Since electromagnetic noise generated from electronic components has different frequency components for each component, it is possible to reduce the influence of noise from specific electronic components on the antenna characteristics by appropriately changing the position and mode in which the antenna resonates.

[0198] Furthermore, by providing the feed point 361 of the inverted F antenna 360 at a location away from the V2X antenna 20, electromagnetic coupling between the inverted F antenna 360 and the V2X antenna 20 can be suppressed, thereby improving the isolation between the antennas.

[0199] Furthermore, even with such an antenna device 340A, the directivity of the V2X antenna 20 can be improved, just as with the antenna device 340. In addition, since the wall section 131F and the base 101 function as antenna elements of the inverted F antenna 360, the number of antennas mounted on the antenna device 340 can be increased without increasing the size of the antenna device 340A.

[0200] ==Summary== According to this specification, antenna devices in the following embodiments are provided.

[0201] (Aspect 1) Aspect 1 is an antenna device comprising a base and a plurality of antennas arranged on the base, wherein the plurality of antennas include a first antenna corresponding to a first frequency band and a second antenna corresponding to a second frequency band lower than the first frequency band, the first antenna includes a planar portion, the second antenna includes an element, the element includes a first slit extending along a first direction from the end on the side where the first antenna is located, and the length of the first slit along the first direction is 1 / 16 or more of the wavelength of the first frequency band.

[0202] According to the above embodiment, the FM antenna element 500 includes a slit S1 that extends in the Y direction by a length L1 of 1 / 16 or more of the wavelength of the first frequency band from the end E1 on the GNSS antenna 60 side. Therefore, according to the above embodiment, it is possible to prevent deterioration of the characteristics of the GNSS antenna 60 and to improve the gain at high elevation angles.

[0203] (Aspect 2) In aspect 2, the element includes a first open end and a second slit extending from the first open end along a second direction different from the first direction, and the length along the first direction from the end on the first antenna side to the first open end is 1 / 4 or less of the wavelength.

[0204] According to the above embodiment, since the FM antenna element 500 includes a slit S2, the gain of the GNSS antenna 60, especially at high elevation angles, can be improved.

[0205] (Aspect 3) In aspect 3, the element includes a second open end and a third slit extending from the second open end along the second direction, and the length along the first direction from the first open end to the second open end is 1 / 4 or less of the wavelength.

[0206] According to the above embodiment, the FM antenna element 500 has slits S2 and S3 in addition to slit S1, which improves the gain of the GNSS antenna 60, especially at high elevation angles.

[0207] (Aspect 4) Aspect 4 is an antenna device comprising a base and a plurality of antennas arranged on the base, wherein the plurality of antennas include a first antenna corresponding to a first frequency band and a second antenna corresponding to a second frequency band higher than the first frequency band, and in a plan view, the first antenna is located at the first end of the base in a first direction, and the second antenna is located at the second end of the base opposite to the first end in the first direction.

[0208] According to the above embodiment, since the GNSS antenna 60 is positioned as far away from the TEL antenna 10 on the base 101, the influence of radio waves transmitted from the TEL antenna 10 on the GNSS antenna 60 can be suppressed.

[0209] (Aspect 5) Aspect 5 is an antenna device comprising a base, a plurality of antennas arranged on the base, and a cable, wherein the plurality of antennas include a first antenna corresponding to a first frequency band, a second antenna corresponding to a second frequency band higher than the first frequency band, and a third antenna corresponding to a third frequency band higher than the first frequency band, the cable transmits a first signal from the first antenna and a second signal from the second antenna, and the first antenna is located between the second antenna and the third antenna.

[0210] According to the above embodiment, since the AM antenna 40 is positioned between the DAB antenna 31 and the FM antenna 50, interference between the DAB antenna 31 and the FM antenna 50 can be prevented.

[0211] (Aspect 6) In aspect 6, the base has a first portion and a second portion located at a higher position than the first portion, and the plurality of antennas have planar antennas, and the planar antennas are arranged in the second portion.

[0212] According to the above embodiment, since the SXM antenna 30 or GNSS antenna 60, which is a planar antenna, is placed in the 21st section 212A or the 22nd section 212B, even if the 21st section 212A and the 22nd section 212B are placed at a higher position than the 11th section 211A and the 12th section 211B, the upper end of the SXM antenna 30 or GNSS antenna 60 will not be higher than the upper end of the antennas placed in the 11th section 211A and the 12th section 211B. As a result, in a top view, the position of the vehicle interior ceiling 3 in the Z direction of the section where the 21st section 212A and the 22nd section 212B are placed can be placed at a higher position, thereby widening the vehicle interior space.

[0213] (Aspect 7) In aspect 7, the base and the plurality of antennas are covered by a cover, the plurality of antennas having antennas extending along a third direction different from the first direction and a second direction different from the first direction, and the cover has a first part and a second part that protrudes from the first part and has a space formed for housing the antennas extending along the third direction.

[0214] According to the above embodiment, the cover 202 has a protrusion 222 in which a housing space SP is formed, so the upper end portion of the V2X antenna 20 is housed in the housing space SP. As a result, the upper end portion of the V2X antenna 20 is positioned higher than that of other antennas, making it less susceptible to interference from other antennas. Therefore, the V2X antenna 20 can suppress horizontal gain reduction and directivity degradation.

[0215] (Aspect 8) In aspect 8, a cylindrical wall is provided, and the plurality of antennas have antennas extending along a third direction different from each of the first direction and a second direction different from the first direction, the antennas extending along the third direction are located at the center of the cylindrical wall, and the radius of the cylindrical wall is 1 / 2 or more of the wavelength of the corresponding frequency of the antennas extending along the third direction.

[0216] According to the above embodiment, the horizontal directivity of the V2X antenna 20 is affected by the cylindrical wall portion 131. Therefore, if the radius R of the wall portion 131 is 1 / 2 or more of the wavelength of the corresponding frequency of the V2X antenna 20, the horizontal directivity of the V2X antenna 20 will have a smaller gain deviation and will approach a circular shape. In other words, the degradation of the horizontal directivity of the V2X antenna 20 can be suppressed.

[0217] (Aspect 9) In aspect 9, the antenna device is positioned spaced apart from a conductive wall, and the plurality of antennas have antennas extending along a third direction different from each of the first direction and a second direction different from the first direction, and the wall has a slot, the slot having a length of half the wavelength of the corresponding frequency of the antenna extending along the third direction.

[0218] According to the above embodiment, the radio waves emitted from the V2X antenna 20 are more likely to pass through the slot 5S and exit the recess 6. Therefore, the gain of the V2X antenna 20 is improved in the direction in which the slot 5S is located relative to the V2X antenna 20.

[0219] (Aspect 10) In aspect 10, the base is positioned spaced apart from the conductive wall, and the plurality of antennas have antennas extending along a third direction different from each of the first direction and a second direction different from the first direction, the antennas extending along the third direction are located outside the wall.

[0220] According to the above embodiment, since the V2X antenna 151 is located outside the frame 5, the V2X antenna 151 is less affected by the frame 5. Therefore, the horizontal directivity of the V2X antenna 151 can reduce the gain deviation.

[0221] (Aspect 11) In aspect 11, the antenna device is arranged inside a conductive wall surrounding the antenna device, the plurality of antennas include a fourth antenna and a fifth antenna corresponding to a predetermined frequency band, the fourth antenna and the fifth antenna extend along a first direction, a second direction different from the first direction and a third direction different from each other, and the distance between the fourth antenna and the fifth antenna is 1.8 to 3.2 times the wavelength of the predetermined frequency band.

[0222] According to the above embodiment, by setting the distance D between the V2X antennas 20A and 20B, which are arranged inside the frame 5, to 1.8 to 3.2 times the wavelength of a predetermined frequency band, the deviation in the horizontal gain of the V2X antennas 20A and 20B is reduced. In other words, the degradation of the horizontal directivity of the V2X antennas 20A and 20B can be suppressed.

[0223] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. Furthermore, the present invention may be modified or improved without departing from its spirit, and it goes without saying that the present invention includes equivalents thereof.

[0224] 5 Frame (wall), 5S slot, 10 TEL antenna (first antenna), 20 V2X antenna (antenna extending along the third direction), 20A V2X antenna (fourth antenna), 20B V2X antenna (fifth antenna), 30 SXM antenna (planar antenna), 31 DAB antenna (third antenna), 40 AM antenna (first antenna), 50 FM antenna (second antenna), 60 GNSS antenna (first antenna, second antenna, planar antenna), 100, 110, 120, 130, 140, 150, 160 Antenna equipment, 101, 201 Base, 202 Cover, 131 Wall section, 161 Frame (wall), 211A Eleventh section, 211B Twelfth section (first section), 212A Twenty-first section (second section), 212B Part 22 (Part 2), 221 Upper part (Part 1), 222 Protruding part (Part 2), 500 FM antenna element (Element), 812 Cable, E2 Open end (First open end), E3 Open end (Second open end), S1 Slit (First slit), S2 Slit (Second slit), S3 Slit (Third slit)

Claims

1. An antenna device comprising: a base; and a plurality of antennas arranged on the base, wherein the plurality of antennas include: a first antenna corresponding to a first frequency band; and a second antenna corresponding to a second frequency band lower than the first frequency band; the first antenna includes a planar portion; the second antenna includes an element; the element includes a first slit extending along a first direction from the end on the side where the first antenna is located; and the length of the first slit along the first direction is 1 / 16 or more of the wavelength of the first frequency band.

2. The antenna device according to claim 1, wherein the element includes a first open end, and includes a second slit extending from the first open end along a second direction different from the first direction, and the length along the first direction from the end on the first antenna side to the first open end is 1 / 4 or less of the wavelength.

3. The antenna device according to claim 2, wherein the element includes a second open end and a third slit extending from the second open end along the second direction, and the length along the first direction from the first open end to the second open end is 1 / 4 or less of the wavelength.

4. An antenna device comprising: a base; and a plurality of antennas arranged on the base, wherein the plurality of antennas include: a first antenna corresponding to a first frequency band; and a second antenna corresponding to a second frequency band higher than the first frequency band, and in a plan view, the first antenna is located at the first end of the base in a first direction; and the second antenna is located at the second end of the base opposite to the first end in the first direction.

5. An antenna device comprising a base, a plurality of antennas arranged on the base, and a cable, wherein the plurality of antennas include a first antenna corresponding to a first frequency band, a second antenna corresponding to a second frequency band higher than the first frequency band, and a third antenna corresponding to a third frequency band higher than the first frequency band, the cable transmits a first signal from the first antenna and a second signal from the second antenna, and the first antenna is located between the second antenna and the third antenna.

6. The antenna device according to any one of claims 1 to 5, wherein the base has a first portion and a second portion located at a higher position than the first portion, the plurality of antennas have planar antennas, and the planar antennas are arranged in the second portion.

7. An antenna device according to any one of claims 1 to 5, comprising a cover that covers the base and the plurality of antennas, wherein the plurality of antennas have antennas extending along a third direction different from each of the first direction and a second direction different from the first direction, and the cover has a first part and a second part that protrudes from the first part and has a space formed for housing the antennas extending along the third direction.

8. An antenna device according to any one of claims 1 to 5, comprising a cylindrical wall, wherein the plurality of antennas have antennas extending along a third direction different from each of the first direction and a second direction different from the first direction, the antennas extending along the third direction are positioned at the center of the cylindrical wall, and the radius of the cylindrical wall is 1 / 2 or more of the wavelength of the corresponding frequency of the antennas extending along the third direction.

9. The antenna device according to any one of claims 1 to 5, wherein the antenna device is positioned spaced apart from a conductive wall, the plurality of antennas have antennas extending along a third direction different from each of the first direction and a second direction different from the first direction, the wall has a slot, and the slot has a length of half the wavelength of the corresponding frequency of the antenna extending along the third direction.

10. The antenna device according to any one of claims 1 to 5, wherein the base is positioned spaced apart from a conductive wall, and the plurality of antennas have antennas extending along a third direction different from each of the first direction and a second direction different from the first direction, and the antennas extending along the third direction are located outside the wall.

11. The antenna device according to any one of claims 1 to 5, wherein the antenna device is arranged inside a conductive wall surrounding the antenna device, the plurality of antennas include a fourth antenna and a fifth antenna corresponding to a predetermined frequency band, the fourth antenna and the fifth antenna extend along a first direction, a second direction different from the first direction and a third direction different from each other, and the distance between the fourth antenna and the fifth antenna is 1.8 to 3.2 times the wavelength of the predetermined frequency band.

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