JP2002151934A - System for common use for communication between radar system and inter-vehicle communication system and on- vehicle antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle antenna that is used in common in a radar system mounted on a vehicle and an inter-vehicle communication system. SOLUTION: The on-vehicle antenna 20 is configured such that its beam center direction can mechanically be scanned in a reciprocating way within a prescribed angular range, the on-vehicle antenna 20 provides a beam characteristic with a narrow width that is a requirement for finding an object at the outside of the vehicle with respect to a radar unit 100 connected to a 1st feeder terminal 20a and provides a wide beam characteristic that copes with a beam width being a requirement for communication between the own vehicle and vehicles before and after the own vehicle with addition of the scanning range of the beam center with respect to an inter-vehicle communication unit 110 connected to a 2nd feeder terminal 20b. While the beam center direction of the on-vehicle antenna 20 is scanned in a reciprocating way, the radar unit 100 radiates a radar wave and receives the reflected wave to find the object outside the vehicle and the inter-vehicle communication unit 110 makes communication between the own vehicle and the vehicles before and after the own vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for sharing a vehicle-mounted antenna between a radar system mounted on a vehicle and a communication system between vehicles.

[0002]

2. Description of the Related Art At present, ITS (Intelligent Transport System)
Various efforts have been made toward construction, and as one of the systems, the development of automotive radar using millimeter waves has been promoted. This radar system is a system which performs a forward or backward search by a radar during traveling and supports driving so that the vehicle can travel safely.

[0003] Further, as a more advanced system, a system for automatically transporting a plurality of vehicles in a short inter-vehicle distance to improve transportation efficiency has been studied. In this system, communication of information on driving control such as an accelerator, a brake, and a steering wheel necessary for maintaining platooning is performed between the front and rear vehicles.

In the future, various systems as described above will be mounted on automobiles, and a safe and efficient road traffic system will be realized.

[0005]

However, in radar search, it is necessary to scan a relatively narrow beam with a narrow beam in order to increase the accuracy of object identification. It is necessary to fix a beam narrower than the scanning range of the radar beam so that stable communication can be always performed between the two systems, and the conditions required for the antenna are greatly different between the two systems.

For this reason, when the radar system and the inter-vehicle communication system are mounted on the same vehicle as described above, an antenna must be provided for each system. It is very difficult to secure space for mounting separate antennas for the two systems.

For this reason, there is a strong demand for a vehicle-mounted antenna that can be shared by the radar system and the inter-vehicle communication system.

An object of the present invention is to provide a radar / vehicle communication shared system and an on-vehicle antenna apparatus which satisfy this demand.

[0009]

In order to achieve the above object, a radar / vehicle communication sharing system according to claim 1 of the present invention is provided so that the center direction of a beam can be mechanically reciprocated within a predetermined angle range. When the vehicle-mounted antenna thus configured and the beam center direction of the vehicle-mounted antenna are scanned back and forth, a radar wave is emitted from the vehicle-mounted antenna, and a reflected wave of the radar wave is received. A radar / vehicle-to-vehicle communication shared system comprising a radar device for searching for and a vehicle-to-vehicle communication device that communicates between front and rear vehicles by sharing the vehicle-mounted antenna in which the beam center direction is scanned. The on-vehicle antenna has a narrow beam characteristic required for searching for an object outside the vehicle with respect to the radar device, and has a narrow beam characteristic required for communication between the front and rear vehicles with respect to the inter-vehicle communication device. And it is configured to indicate a wide beam characteristic plus scanning range of the beam center to beam width.

A vehicle-mounted antenna device according to a second aspect of the present invention is a vehicle-mounted radar system for exploring an object outside the vehicle and a vehicle-to-vehicle communication system for performing communication between front and rear vehicles. Antenna, an antenna body having a radio wave transmitting / receiving surface on one surface side, a first feeding terminal and a second feeding terminal independent of each other, and a beam characteristic of the antenna body with respect to the first feeding terminal is: A first power supply unit that couples between the first power supply terminal and the antenna body so as to have a narrow beam characteristic required for searching for an object outside the vehicle in the radar system; and a second power supply terminal. The beam characteristics of the antenna body with respect to are obtained by adding the scanning range of the beam center required by the radar system to the beam width required for communication between the front and rear vehicles in the inter-vehicle communication system. The coupling between the second power supply terminal and the antenna main body such that the beam characteristics of the wide-2
And at least one of the antenna body, the first feeder, and the second feeder such that the center direction of the beam of the antenna main body reciprocates within a beam scanning range required by the radar system. Rotating means for mechanically reciprocating the part.

According to a third aspect of the present invention, in the vehicle-mounted antenna device according to the second aspect, the antenna main body is formed as a focused reflection type that reflects a radio wave on one surface side, and Is configured to radiate an input wave to the first power supply terminal from the substantially focal position of the antenna main body to the one surface side, and the second power supply unit is configured to transmit the input wave to the second power supply terminal. Split the input wave,
The antenna is configured to radiate toward the one surface side from a plurality of positions sandwiching the focal position of the antenna main body.

According to a fourth aspect of the present invention, there is provided the on-vehicle antenna device according to the second aspect, wherein the antenna body has a plurality of antenna elements arranged on a substantially flat surface. The first power supply unit is configured to supply an input wave to the first power supply terminal to the plurality of antenna elements in substantially the same phase, and the second power supply unit includes an input to the second power supply terminal. It is configured to feed a wave to the plurality of antenna elements at different phases.

According to a fifth aspect of the present invention, there is provided the on-vehicle antenna device according to the fourth aspect, wherein each of the antenna elements is disposed between the ground conductor and the ground conductor. A dielectric substrate forming a transmission path for transmitting electromagnetic waves from one end side to the other end side, and is loaded at a predetermined interval on the surface of the dielectric substrate, and a loading body that leaks electromagnetic waves from the transmission path, The first power supply unit and the second power supply unit are configured to supply electromagnetic waves to one end of the transmission path.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, the operation in the case of transmitting a radio wave is mainly described. However, as in a general antenna, the in-vehicle antenna of this embodiment has reversibility in transmission and reception. Has the opposite effect.

FIG. 1 shows the overall configuration of a radar / vehicle communication sharing system according to an embodiment of the present invention.

This radar / vehicle communication shared system is:
It constitutes a part of a traveling support system in one vehicle, and includes a vehicle-mounted antenna 20 and a radar device 10 that uses the vehicle-mounted antenna 20 to search, for example, an object in front of the vehicle outside.
0 and an inter-vehicle communication device 110 that communicates driving information between a vehicle traveling ahead using an on-vehicle antenna 20.

The radar device 100 uses an FMCW modulation method. The modulation method of the radar apparatus 100 may be not only the FMCW method but also a pulse method, a spread spectrum method, or the like.

The radar device 100 includes a triangular wave generator 1
The output signal in the millimeter-wave band of the VCO (voltage controlled oscillator) 102 is frequency-modulated by the triangular wave output from 01, and the output signal is input to the power amplifier 104 via the coupler 103 and amplified, and is output via the circulator 105. The signal is input to the first power supply terminal 20a of the vehicle-mounted antenna 20.

A signal input from the first power supply terminal 20a of the vehicle-mounted antenna 20 via the circulator 105 is amplified by an LNA (low noise amplifier) 106,
This amplified signal is input to a mixer 107 and
The beat signal of the frequency component of the difference with the signal from
This beat signal is input to the signal processing unit 108.

The signal processor 108 obtains information such as the distance to an object outside the vehicle and the relative speed of the object from the frequency and level of the beat signal. Also, the signal processing unit 108
The driving support device 12 receives scanning direction information from the rotating unit 29 of the vehicle-mounted antenna 20 and uses the distance and relative speed obtained for each scanning direction information as target information as will be described later.
Output to 0.

The inter-vehicle communication device 110 detects speed information of the own vehicle, operation information of an accelerator, a brake, a steering wheel and the like as driving information by a plurality of sensors 111 installed in the own vehicle, and multiplexes the driving information. The multiplexed signal is input to a modulator 113 to generate an intermediate frequency signal modulated by the multiplexed signal. The intermediate frequency signal is converted into a millimeter wave band by a frequency converter 114, and the power amplifier 11
5, and is output to the second power supply terminal 20b of the vehicle-mounted antenna 20 via the circulator 116. In addition,
The frequency of the signal in the millimeter wave band output by the inter-vehicle communication device 110 is set near the frequency of the signal output by the radar device 100 and not to overlap each other.

A signal input from the second power supply terminal 20b of the on-vehicle antenna 20 via the circulator 116 is amplified by the LNA 117 and the frequency converter 11
The signal is converted into an intermediate frequency signal by 8, the driving information of the preceding vehicle is demodulated by the demodulator 119, and output to the driving support device 120.

The driving support device 120 is a radar device 100
Based on the target information from the vehicle and the driving information of the other vehicle from the inter-vehicle communication device 110, the vehicle performs correction control of the speed and the traveling trajectory so that the vehicle can travel safely and efficiently, Urge to fix.

On the other hand, the in-vehicle antenna 20 shared by the radar apparatus 100 and the inter-vehicle communication apparatus 110 includes first and second power supply terminals 20a and 20b independent of each other, an antenna body 21, and a first power supply unit 23. , The second power supply unit 26
And rotating means 29.

The antenna body 21 transmits and receives radio waves on one surface side, and is composed of, for example, a reflector antenna, an array antenna, and the like.

The first power supply section 23 includes a first power supply terminal 20.
2, the antenna main body 21 and the first antenna main body 21 have a narrow (half-width Wr) beam characteristic Br required for searching for an object outside the vehicle by the radar system as shown in FIG. Between the power supply terminals 20a.

In the second power supply section 26, the beam characteristic of the antenna main body 21 with respect to the second power supply terminal 20b is such that its beam center substantially matches the beam center of the radar, and the beam width (half width) Wc Is the beam width W of the beam characteristic Bc 'required for communication between the preceding and following vehicles in the inter-vehicle communication system.
The antenna main body 21 and the second power supply terminal 20b are coupled to each other so as to have a wide beam characteristic Bc obtained by adding a beam scanning range φr required for the radar system to c ′.

The rotating means 29 mechanically reciprocates at least a part of the antenna main body 21 and the first and second power supply portions 23 and 26 so that the beam center direction of the horizontal plane of the antenna main body 21 is shifted in the traveling direction of the vehicle. And reciprocal scanning within a scanning range φr required by the radar system.

As described above, in the radar / vehicle communication shared system of the embodiment, the beam characteristic of the antenna body 21 is such that the beam characteristic Br of the narrow width Wr required for the radar system for the first power supply terminal 20a is obtained. The second power supply terminal 20b has a beam characteristic Bc of a wide width Wc 'obtained by adding the scanning range φr of the radar system to the beam width Wc' required in the inter-vehicle communication system. The vehicle-mounted antenna 20 whose beam direction is scanned within the scanning range φr to be used is shared.

For this reason, for example, FIG.
As described above, even when the center of the radar beam Br of the vehicle-mounted antenna 20 is moved to the end of the scanning range by the rotating means 29, the inter-vehicle communication beam Bc is centered on the traveling direction required in the inter-vehicle communication system. The communication range of the width Wc 'is covered, and communication between vehicles can be performed stably.

Also, by using such an on-board antenna 20, it is not necessary to separately provide an antenna for each system, so that the entire driving support system can be significantly reduced in size and mounted on a vehicle having a small body. Becomes possible.

Here, a case has been described in which the search for an object in front of the vehicle and the inter-vehicle communication are performed. However, in the case where the search for an object and the inter-vehicle communication are performed before and after the vehicle,
Another set of the on-vehicle antenna 20, the radar device 100, and the inter-vehicle communication device 110 are provided, and target information on an object behind the radar device 100 and driving information from a following vehicle from the inter-vehicle communication device 110 are provided by the driving support device 120 Output to the driving support device 120.
However, based on the front and rear target information and the driving information of the preceding and following vehicles, the vehicle controls the speed and the traveling trajectory so as to allow the vehicle to travel safely and efficiently, and prompts the driver to correct them.

Next, a specific configuration example of the vehicle-mounted antenna 20 used in the radar / vehicle communication shared system will be described.

FIGS. 4 and 5 show an embodiment of the vehicle-mounted antenna 20. FIG. The antenna body 21 of the vehicle-mounted antenna 20 is of a focused type in which radio waves are reflected by a concave parabolic reflecting surface 21a, and radiation and incidence of radio waves from the parabolic reflecting surface 21a are not hindered by a feeding unit described later. Thus, the theoretical parabola center line L is offset so as to pass through a position lower than the lower end of the parabolic reflecting surface 21a by a predetermined distance.

The parabolic reflecting surface 21a of the antenna body 21
A first power supply unit 23 and a second power supply unit 26 are arranged at positions facing the power supply unit. These first and second power supply units 23 and 26 are fixedly supported on the vehicle body by a support mechanism (not shown).

The first power supply section 23 has a horn-shaped radiation section 24.
And a waveguide portion 25, which is arranged so that the radiation center of the radiation portion 24 at one end coincides with the focal position F of the parabolic reflection surface 21a, and the waveguide portion 25 at the other end. At the end of the first power supply terminal 20a, and radiates an input wave (radar transmission wave) from the first power supply terminal 20a so as to hit almost the entire surface of the parabolic reflection surface 21a.

As shown in FIG. 6, the light is radiated from the radiating portion 24 of the first feeding portion 23 and
The radio wave reflected at a is radiated in a state where the equiphase plane Ha is orthogonal to the parabola center line L.

Therefore, the input wave (radar transmission wave) to the first power supply terminal 20a is centered on the direction along the parabola center line L (this is defined as the 0 ° direction of the horizontal plane) as shown in FIG. The width Wr is narrow (for example, the half width is 3 ° to 4 °).
°) Emitted with beam characteristic Br. This beam characteristic Br
Is set to a width suitable for searching for obstacles by a vehicle-mounted radar.

The second power supply section 26 is disposed at a plurality of symmetric positions Pa and Pb (positions on the focal plane of the parabolic reflection surface 21a) on both sides of the radiation section 24 of the first power supply section 23. In this example, two (two in this example) radiating portions 27a and 27b are provided on one end side, and an input wave (transmission wave for inter-vehicle communication) from the second power supply terminal 20b is branched in the same phase by a branching portion 28 made of a waveguide. Then, one of the branched waves is radiated from the radiating portion 27a to the parabolic reflecting surface 21a, and the other branched wave is radiated to the radiating portion 27b.
Radiate from the surface to the parabolic reflecting surface 21a.

As shown in FIG. 6, the radiating portions 27a,
The equiphase surfaces Ha and Hb of the electromagnetic waves radiated from the parabola reflection surface 21a and radiated from the parabola reflection surface 21a are slightly inclined symmetrically with respect to the parabola center line L. For this reason, as shown in FIG. 7, the electromagnetic waves radiated from the radiating portions 27a and 27b respectively have slightly wider beam characteristics Bc1 and Bc2.
Will be radiated.

The centers and widths of the beam characteristics Bc1 and Bc2 are determined by the radiating portions 27a and 2b with respect to the parabolic reflecting surface 21a.
7b, the beam width of the electromagnetic wave radiated from the radiating portions 27a, 27b to the parabolic reflecting surface 21a, and the like. Here, as shown in FIG. 7, the two beam characteristics Bc1 and Bc2 are combined. The obtained characteristic Bc has substantially the same center as the beam characteristic Br for the first power supply terminal 20a, and it is necessary to perform communication between the front and rear vehicles when it is assumed that the beam direction of the vehicle-mounted antenna 20 is not scanned. The gain becomes substantially uniform at a divergence angle Wc (eg, ± 15 °) substantially equal to the beam width Wc ′ (eg, 5 ° half-width) plus the search range φr (eg, ± 10 °) of the radar system. Is set in advance as follows.

The antenna main body 21 is supported by a rotating means 29. The rotating means 29 includes a rotation driving unit 29a.
And a support portion 29b having one end fixed to the rotation drive portion 29a and the other end fixed to the back surface 21b of the antenna body 21.
And the antenna main body 21 is
A rotation axis is a line passing perpendicularly through the center of a, and an angle range corresponding to a beam scanning range (for example, ± 10 °) required by the radar system on a horizontal plane about the traveling direction of the vehicle (in this case, rotation) It becomes ± 5 ° from the relationship between the rotation angle and the reflection angle of the reflector).

As shown in FIG. 3, the beam center of the on-vehicle antenna 20 is reciprocally scanned in the radar scanning range by the rotation driving by the rotating means 29, and the beam center moves to the end of the scanning range. Even in this state, the beam characteristics Bc cover the communication range of the width Wc 'required in the inter-vehicle communication system, and the inter-vehicle communication can be performed stably.

That is, as shown in FIGS. 8A and 8B, even when the beam center is scanned at the maximum angle on the + side (left side) by the radar scanning of the own vehicle 1, the beam side is kept on the negative side (right side). Even when the scanning is performed at the maximum angle, the beam characteristics Bc of the second power supply terminal 20b sufficiently cover the preceding other vehicle 2, and the preceding other vehicle 2 is not affected by the beam scanning by the radar. Between the vehicles can be stably performed.

Further, in the vehicle-mounted antenna 20, the antenna body 21 is reciprocally driven to rotate, and the first and second power supply sections 23 and 26 are fixed, so that the antenna body 21 and the first and second power supply sections 23 and 26 are fixed. As compared with the method of integrally rotating the power supply units 23 and 26, the movable space is small, and the power supply units 23 and 26 can be mounted in a narrow position, and the first and second power supply terminals 20 can be mounted.
Since a and 20b are also fixed, it is possible to easily connect the radar device 100 and the inter-vehicle communication device 110 with a fixed transmission path.

As described above, when the antenna main body 21 is driven to rotate with respect to the first and second power supply portions 23 and 26, the first and second power supply to the parabolic reflecting surface 21a of the antenna main body 21 are performed. Since the positions of the radiation centers of the portions 23 and 26 relatively change, the beam characteristics Br and Bc are different depending on whether the beam center is at the center of the scanning range or at the end.
However, when the scanning range is relatively narrow as described above, the characteristic change is relatively small, and there is no significant effect on object detection outside the vehicle or communication between vehicles.

However, if there is room in the mounting space,
The first and second power supply units 23 and 26 may be supported by the rotation unit 29 together with the antenna main body 21. In this case, the first and second power supply units 2 for the antenna body 21 are used.
Since the relative positions of 3 and 26 do not change, the beam characteristics do not change even if the center direction of the beam changes.

The beam characteristic Bc for the inter-vehicle communication described above combines two symmetrical characteristics, so that the change in gain at the center is slightly large and the characteristics on both sides are slow. Can be improved by increasing the number of radiating sections of the second feeding section 26.

For example, as shown in FIG.
To 27d are arranged on both sides of the radiating section 24 of the first feeding section 23, and the input wave to the second feeding terminal 20b is branched into four at the splitting section 28 and the parabolic reflections from the radiating sections 27a to 27d. Radiates to the surface 21a.

In this case, as shown in FIG.
Since the widths of the beam characteristics Bc1 to Bc4 for a to 27d can be narrowed, the change in the gain of the beam characteristics Bc obtained by combining them becomes small, and the characteristics of both sides become steep. Car-to-car communication can be performed.

As a method of expanding the beam width with a small radiating portion, there is a method of narrowing the beam width radiated from the radiating portion to the parabolic reflecting surface 21a to reduce the area (gain) of the parabolic reflecting surface 21a. . In this case, as shown in FIG.
The diameters of a and 27b may be increased.

However, the radiation section 27 of the second power supply section 26
If the diameters of a and 27b are increased, there may be cases where the first and second power supply units 23 cannot be arranged side by side in contact with the radiation unit 24. In that case, as shown in FIG.
What is necessary is just to displace the 27 b before (or after) the radiating section 24.

In the above-described in-vehicle antenna 20, the one having the concave parabolic reflection surface 21a is used as the reflection type antenna body 21 having a focal point. However, as in the in-vehicle antenna 30 shown in FIG. 31
A plurality of patch antenna elements 33 are formed by patterning on one surface of a flat dielectric substrate 32, and the first and second feeding portions 23 and 26 are formed by these patch antenna elements 33.
May be reflected.

In this case, the plurality of patch antenna elements 33
Are set so that the radio wave radiated from the first power supply unit 23 is reflected with an equal phase surface substantially parallel to one surface of the dielectric substrate 32, and the radio wave radiated from the second power supply unit 26 is set. May be set to be reflected with an equal phase plane that is inclined symmetrically to one surface of the dielectric substrate 32.

It should be noted that such a patch antenna element 33
The antenna body 31 made of
3 can be regarded as a reflection type having a focal position determined by the size of 3. In this case, if the antenna main body 31 is driven to rotate by the rotation means 35, the movable space can be reduced, and the antenna can be mounted in a narrow position. Can be done, and
First and second power supply terminals 20a, 20b and radar device 10
0 and the vehicle-to-vehicle communication device 110 can be easily connected by a fixed transmission line.

The above-mentioned vehicle-mounted antennas 20 and 30 are configured so that the radio waves radiated from the first and second power supply portions 23 and 26 are reflected by the antenna main bodies 21 and 31. Like a vehicle-mounted antenna 40 shown in FIG. 17, the antenna main body 41 may be formed of a leaky wave type that leaks radio waves from a transmission path.

The antenna body 4 of the vehicle-mounted antenna 40
Reference numeral 1 denotes a ground plane conductor 42 formed of a metal into a substantially rectangular flat plate shape.
A dielectric substrate 43 disposed so as to overlap one surface side of the ground plane conductor 42 and forming a transmission path for transmitting an electromagnetic wave from one end side to the other end side between the ground plane conductor 42 and the surface of the dielectric substrate 43 And a metal strip 44 serving as a loading body for leaking electromagnetic waves from the transmission line, and a wavefront converting section 46.

Here, the transmission line formed between the ground plane conductor 42 and the dielectric substrate 43 is formed by a large number of minute width continuous transmission lines in the width direction. Is loaded with the metal strip 44, it can be regarded that a large number of leaky wave antenna elements having a minute width are continuous in the width direction.

A plurality of narrow-bar dielectric substrates are arranged side by side at predetermined intervals to form a plurality of transmission lines at predetermined intervals, and a metal strip is formed on each transmission line to form a plurality of leaky wave antenna elements. May be formed.

The intensity of the electromagnetic waves leaking from the plurality of transmission lines is determined by the width s of the metal strip 44, and the direction of leakage on the vertical plane is determined by the distance d between the metal strips 44.
Here, it is assumed that the leakage direction on the vertical plane is set to be a direction orthogonal to the surface of the dielectric substrate 43.

The dielectric substrate 43 is supported by spacers 45 so as to slightly float from the ground plate conductor 42 in order to provide an air layer between the dielectric substrate 43 and the ground plate conductor 42 to reduce conductor loss due to the ground plate conductor 42. At the top end,
A tapered portion 43a for matching the wavefront converter 46 is formed.

The wavefront converter 46 converts a spherical wave radiated from a feeder described later into a cylindrical wave, converts the cylindrical wave into a plane wave, and guides it to one end of the dielectric substrate 43. Here, a spherical wave is converted into a cylindrical wave by an H-plane spectral horn 47 provided on the back surface side of the ground plane conductor 42, and the cylindrical wave is curved toward an end of the dielectric substrate 43 in an arc shape. 48, the ground plane conductor 4
2 is a folded type that converts the light into a plane wave while reflecting so as to be folded back to the dielectric substrate 43 on the front surface side, thereby reducing the overall height of the antenna.

The gap between the upper edge of the ground conductor 42 and the reflector 48 is set to a predetermined size so that the electromagnetic wave can be efficiently turned back.

As the wavefront converter 46, an H-plane spectral horn 47 is arranged on the surface of the ground plane conductor 42 so that its radiation surface faces one end of the dielectric substrate 43. A radio wave lens may be formed by extending the side, and the cylindrical wave radiated from the H-plane spectral horn 47 may be converted into a plane wave by the radio wave lens and guided to the transmission path of the dielectric substrate 43.

The cover 49 of the wavefront conversion section 46 is
8, the electromagnetic wave reflected by the reflector 48 is guided to the dielectric substrate 43 without leaking to the outside from the upper edge of the substrate 8 to the upper part of the tapered portion 43a of the dielectric substrate 43.

H-plane sector horn 4 of wavefront conversion section 46
A first power supply unit 51 and a second power supply unit 54 are provided at the lower end of 7.

As shown in FIG. 18, the first power supply section 51 includes a horn-shaped radiation section 52 and an H-plane sector horn 47.
And the end of the waveguide 53 is a first feed terminal 40a, and an input wave (radar transmission wave) from the first feed terminal 40a is radiated from the radiator 51a as a spherical wave. .

This spherical wave is generated by the H-plane sector horn 47.
Is converted into a cylindrical wave corresponding to the curvature of the reflecting plate 48 and is incident on the reflecting plate 48. The reflecting plate 48 converts the wave into a plane wave Ha having an equal phase plane parallel to the width direction of the dielectric substrate 43. 43 is led to one end side.

For this reason, the electromagnetic waves having the same phase in the width direction are supplied to each transmission line of the antenna main body 41, and the first
7, the beam characteristic Br shown in FIG. 7 is obtained, and as shown in FIG.
Radio waves are radiated from 3 with a narrow (eg, 3 ° to 4 °) beam characteristic Br having a center in a direction orthogonal to the surface and suitable for radar systems.

The second feeding section 54 includes a plurality (two in this example) of radiating sections 55a and 55b arranged at symmetrical positions Pa and Pb on both sides of the radiating section 52 of the first feeding section 51.
And the input wave from the second power supply terminal 40b is branched in the same phase, one of the branched waves (spherical wave) is radiated from the radiating portion 55a to the reflector 48, and the other is radiated. Part 5
There is a branch portion 56 for radiating the light from 5b to the reflection plate 48.

As shown in FIG. 18, the spherical waves radiated from the radiating portions 55a and 55b are converted into cylindrical waves by the H-plane sector horn and are incident on the reflecting plate 48.

For this reason, the reflection plate 48 is
Plane waves Hb and Hc whose equiphase surfaces are inclined symmetrically with respect to the center line of 8 (the phases in the width direction are slightly different) are guided to the dielectric substrate 43.

Therefore, from the dielectric substrate 43, as shown in FIG. 7, a beam characteristic Bc1 having a slightly wider width in a direction inclined at a predetermined angle from the narrow beam Br on the horizontal plane,
A radio wave is radiated with the beam characteristic Bc2 symmetrical to this, and a wide beam characteristic Bc obtained by combining these with the second power supply terminal 40b is obtained. As shown in FIG. Can be obtained.

As described above, the divergence angle Wc of the beam characteristic Bc depends on the radiating portions 55 a and 55 of the second feeder 54.
The beam width (for example, ± 15 °) obtained by adding the radar scanning range φr (for example, ± 10 °) to the beam width Wc ′ (for example, half-width 5 °) required for inter-vehicle communication, depending on the position of b, the radiation beam width, and the like. °).

The rotating means 60 reciprocally rotates the ground plane conductor 42 on a horizontal plane within an angle range corresponding to a radar scanning range (for example, ± 10 °). In addition, this in-vehicle antenna 4
0, the antenna main body 41 and the first and second power supply units 51, 5
4 is integrally rotated, so that the rotation angle range is equal to the radar scanning range.

The vehicle-mounted antenna 40 thus configured
In the case of, as shown in FIGS. 3A and 3B,
Even when the beam center moves to the end of the scanning range, the beam characteristic Bc covers the communication range of the width Wc 'required in the inter-vehicle communication system, and the inter-vehicle communication can be performed stably.

Therefore, as shown in FIG. 8, the beam characteristic Bc of the second power supply terminal 40b always covers the other vehicle 2 in the inter-vehicle communication, and is not affected by the radar beam scanning. The vehicle-to-vehicle communication with the vehicle can be performed stably.

In this vehicle-mounted antenna 40, the whole antenna is rotationally driven. However, as in a vehicle-mounted antenna 40 'shown in FIG.
H-plane sector horn 47 and first and second power supply units 5
1 and 54 are fixed, and only the wavefront converting section 46 'is
With 0, the beam may be rotated about an axis passing horizontally through the center of the reflection surface of the reflection plate 48, and the beam may be scanned back and forth in the center direction.

In this case, however, the cover 47a (ground) of the H-plane sector horn 47 and the wavefront converter 46 '
Since a gap G is formed between the lower edge of the reflector 48 and the electrical conduction, it becomes difficult to maintain electrical continuity. Therefore, a choke 66 parallel to the reflector 48 is formed on the back side of the reflector 48. The impedance when the inside of the gap G is viewed from the entrance of the gap G is made substantially zero.

When the wavefront converter 46 'is rotated in this manner, the relative positions of the first and second feeders 51 and 54 with respect to the reflector 48 change as in the case of the on-vehicle antenna 20 described above. Since the change in distance at the center of the strong electric field is small, the change in the beam characteristics can be small.

In the vehicle-mounted antennas 40 and 40 ', the radiating portions of the first feeding portion 51 and the second feeding portion 54 are horn-shaped, but as shown in FIG. 55a and 55b can also be formed as a dielectric rod antenna type.

Further, the above-mentioned vehicle-mounted antennas 40, 4
In the case of 0 ', a leaky wave type antenna element was used for the antenna main body 41, but the in-vehicle antenna 70 shown in FIG.
Even when the antenna body 71 is formed by an array antenna in which M × N (N is plural and M is 1 or more) micro-strip antenna elements 73 are vertically and horizontally arranged on the surface of the substrate 71 as shown in FIG. By configuring the first and second power supply units 75 and 77 as shown in 23, it is possible to share the radar system and the inter-vehicle communication system.

FIG. 23 shows an example of the configuration of the first and second power supply units 75 and 77 in the case where the number of antenna elements 73 is eight and that is one stage. The input wave from the feeding terminal 70a is branched and fed in phase to all the antenna elements 73 to obtain a narrow beam suitable for radar.

Further, the second power supply unit 77 uses a plurality of delay units 79 to convert the input wave from the second power supply terminal 70 b
For example, branch feeding is performed such that the phase of the four antenna elements 73 on the left side is delayed by a predetermined amount φ in order from the left end, and that of the four antenna elements 73 on the right side is delayed by the predetermined amount φ in order from the right end. A broad beam characteristic having substantially the same center as the radar beam and having a divergence angle obtained by adding the beam scanning range φr by the rotating means 80 to the beam width Wc ′ required for inter-vehicle communication is obtained.

Note that the above-described vehicle-mounted antennas 20, 3
In 0, 40, 40 ', and 70, the input waves to the first and second power supply terminals were supplied to the antenna main body as they were, but between the first power supply terminal and the first power supply unit and to the second power supply. A frequency conversion circuit that performs frequency conversion in both directions is provided between the terminal and the second power supply unit, and each power supply terminal side handles a signal in an intermediate frequency band lower than a frequency band of a radio wave emitted by the antenna. Is also good. In this way, even if the entire antenna is rotated as in the case of the in-vehicle antennas 40 and 70 described above, it is possible to connect the devices of each system with a flexible cable.

[0086]

As described above, the radar of the present invention
The vehicle-to-vehicle communication sharing system includes an in-vehicle antenna configured to be capable of mechanically reciprocatingly scanning the center direction of the beam within a predetermined angle range. A radar device that emits a radar wave from a vehicle-mounted antenna, receives a reflected wave of the radar wave, and searches for an object outside the vehicle, and the vehicle-mounted antenna that is scanned in the direction of the beam center is shared by the vehicle-mounted antenna. A radar / inter-vehicle communication shared system comprising an inter-vehicle communication device that performs communication between vehicles, wherein the on-vehicle antenna has a narrow beam required for the radar device to search for an object outside the vehicle. And a wide beam characteristic obtained by adding the scanning range of the beam center to the beam width required for communication between the preceding and following vehicles. It has been.

For this reason, even when the center direction of the beam of the vehicle-mounted antenna is scanned for the purpose of searching for an object outside the vehicle, the vehicle-to-vehicle antenna can be used to stably perform communication between vehicles.
One in-vehicle antenna can be shared by the radar system and the inter-vehicle communication, and the system for driving assistance can be mounted in a limited space of the vehicle.

The vehicle-mounted antenna according to the present invention is a vehicle-mounted antenna shared by a vehicle-mounted radar system for searching for an object outside the vehicle and an inter-vehicle communication system for performing communication between front and rear vehicles. An antenna body having a radio wave transmitting / receiving surface on one surface side, a first power supply terminal and a second power supply terminal independent of each other, and a beam characteristic of the antenna body with respect to the first power supply terminal is set outside the vehicle by the radar system. A first power supply unit that couples between the first power supply terminal and the antenna main body so as to have a narrow beam characteristic required for searching for an object, and an antenna main body with respect to the second power supply terminal. The beam characteristic is a wide beam characteristic obtained by adding the scanning range of the beam center required by the radar system to the beam width required for communication between the front and rear vehicles in the inter-vehicle communication system. A second power supply unit for coupling between the second power supply terminal and the antenna main body so that the center direction of the beam of the antenna main body reciprocates within a beam scanning range required by the radar system. As
The antenna main body, and a rotating unit for mechanically reciprocatingly rotating at least a part of the first power supply unit and the second power supply unit.

Therefore, by connecting the first power supply terminal to the radar system and connecting the second power supply terminal to the inter-vehicle communication system, even when a narrow beam for radar is scanned by the rotating means. The vehicle-to-vehicle communication can be performed stably, and the radar system and the vehicle-to-vehicle communication system can be shared.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a radar / vehicle communication sharing system of the present invention.

FIG. 2 is a beam characteristic diagram of an on-vehicle antenna used in the radar / vehicle communication shared system of the present invention.

FIG. 3 is a beam characteristic diagram at the time of scanning of an on-vehicle antenna used in the radar / vehicle communication shared system of the present invention.

FIG. 4 is a schematic side view of an on-vehicle antenna according to an embodiment of the present invention.

FIG. 5 is a schematic plan view of an on-vehicle antenna according to an embodiment of the present invention.

FIG. 6 is a diagram for explaining a beam forming process of the vehicle-mounted antenna according to the embodiment of the present invention.

FIG. 7 is a diagram showing beam characteristics of the vehicle-mounted antenna according to the embodiment of the present invention.

FIG. 8 is a diagram showing beam characteristics during traveling of the vehicle-mounted antenna according to the embodiment of the present invention.

FIG. 9 is a diagram showing a modification of a main part.

FIG. 10 is a diagram showing beam characteristics of a modification of FIG. 9;

FIG. 11 is a diagram showing a modification of a main part.

FIG. 12 is a diagram showing a modification of a main part.

FIG. 13 is a schematic perspective view of another embodiment of a vehicle-mounted antenna.

FIG. 14 is a front view of another embodiment of the in-vehicle antenna.

FIG. 15 is a side view of another embodiment.

FIG. 16 is a rear view of another embodiment.

17 is a sectional view taken along line AA of FIG.

FIG. 18 is a diagram for explaining a process of forming a radar beam according to another embodiment.

FIG. 19 is a diagram illustrating beam characteristics according to another embodiment.

FIG. 20 is a diagram showing a modification of the other embodiment.

FIG. 21 is a diagram showing a modification of the main part of another embodiment.

FIG. 22 is a diagram showing a configuration of another embodiment.

FIG. 23 is a diagram showing a configuration example of a main part of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Own vehicle 2 Other vehicle 20 In-vehicle antenna 20a 1st feeding terminal 20b 2nd feeding terminal 21 Antenna main body 21a Parabolic reflection surface 23 1st feeding unit 26 2nd feeding unit 29 Rotating means 30 In-vehicle antenna 31 Antenna Main body 32 Dielectric substrate 33 Patch antenna element 40, 40 'In-vehicle antenna 40a First power supply terminal 40b Second power supply terminal 41 Antenna body 42 Ground plane conductor 43 Dielectric substrate 44 Metal strip 45 Spacer 46, 46' Wavefront conversion unit 47 H-plane sector horn 48 Reflector 49 Cover 51 First feeder 54 Second feeder 60 Rotating means 66 Choke 70 In-vehicle antenna 70a First feeder terminal 70b Second feeder terminal 71 Antenna body 72 Antenna element 75 First power supply unit 77 Second power supply unit 79 Delay unit 80 Rotating means 100 Radar device 110 Vehicle-to-vehicle communication device 120 Driving support device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayuki Fujise 3-4 Hikarinooka, Yokosuka City, Kanagawa Prefecture Within the Communications Research Laboratory, Yokosuka Radio Communication Research Center, Ministry of Posts and Telecommunications (72) Inventor, Akito Kato 3 Hikarinooka, Yokosuka City, Kanagawa Prefecture -4 Ministry of Posts and Telecommunications Research Laboratory Yokosuka Radio Communication Research Center F-term (reference) 5H180 AA01 CC14 FF13 5J021 AA01 BA01 DA03 FA09 FA17 FA25 FA26 FA35 GA08 HA02 HA03 HA04 HA05 HA10 JA07 5J046 AA00 AB05 AB19 MA09 5J070 AB01 AB17 AB24 AC02 AC11 AD08 AD20 AE01 AF03 AG06 AK13 AK27 BF02 BF03 BF30

Claims (5)

[Claims] 1. An on-vehicle antenna configured to mechanically reciprocally scan a center direction of a beam within a predetermined angle range, and the on-vehicle antenna being reciprocally scanned in a beam center direction of the on-vehicle antenna. A radar wave from the antenna
A radar device that receives a reflected wave of the radar wave and searches for an object outside the vehicle; and a vehicle-to-vehicle communication that communicates between front and rear vehicles by using the vehicle-mounted antenna that is scanned in the beam center direction. A radar / vehicle communication shared system comprising a device, wherein the on-vehicle antenna exhibits a narrow beam characteristic required for searching for an object outside the vehicle with respect to the radar device, A radar-vehicle communication shared system characterized by exhibiting a wide beam characteristic obtained by adding a beam width required for communication between the front and rear vehicles and a scanning range of the beam center. 2. An in-vehicle antenna for use in an on-vehicle radar system for exploring an object outside the vehicle and an inter-vehicle communication system for performing communication between front and rear vehicles. An antenna main body having: a first power supply terminal and a second power supply terminal independent of each other; and a beam characteristic of the antenna main body with respect to the first power supply terminal is required for the radar system to search for an object outside the vehicle. A first power supply unit for coupling between the first power supply terminal and the antenna body so as to have a narrow beam characteristic; and a beam characteristic of the antenna body with respect to the second power supply terminal, the inter-vehicle communication system. The second feed end so as to have a wide beam characteristic obtained by adding a beam width required for communication between the front and rear vehicles and a scanning range of a beam center required for the radar system. A second feeding unit that couples the antenna body and the antenna body, the antenna body and the second antenna unit so that a center direction of a beam of the antenna body reciprocates within a beam scanning range required by the radar system. A vehicle-mounted antenna comprising: a rotation unit configured to mechanically reciprocate at least a part of the first power supply unit and the second power supply unit. 3. The antenna main body is formed in a focused reflection type that reflects a radio wave on one surface side, and the first power supply unit transmits an input wave to the first power supply terminal to a substantially focal position of the antenna main body. From the plurality of positions sandwiching the focal position of the antenna body to the one surface side, wherein the second power supply unit branches the input wave to the second power supply terminal. The vehicle-mounted antenna according to claim 2, wherein the antenna is configured to radiate. 4. The antenna main body includes a plurality of antenna elements arranged on a substantially flat one surface side, and the first power supply unit transmits an input wave to the first power supply terminal to the plurality of antenna elements. The second power supply unit is configured to supply an input wave to the second power supply terminal to the plurality of antenna elements with different phases. The in-vehicle antenna according to claim 2, wherein 5. Each of the antenna elements includes: a ground plane conductor; a dielectric substrate disposed on the ground plane conductor and forming a transmission path for transmitting an electromagnetic wave from one end to the other end between the ground plane conductor and the ground plane conductor; A loading body that is loaded on the surface of the dielectric substrate at a predetermined interval and leaks electromagnetic waves from the transmission path, wherein the first power supply unit and the second power supply unit transmit electromagnetic waves to one end of the transmission path. The in-vehicle antenna according to claim 4, wherein the antenna is configured to supply power.