JPH09297173A - Multi-beam radar antenna and module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a further miniaturized multi-beam radar antenna and a multi-antenna radar module realizing high resolution using this radar antenna. SOLUTION: In an antenna of a multi-beam radar device provided with a plurality of transmitting-receiving channels that transmit high frequency signal beams and receive the reflected wave, a transmitting-receiving antenna of each transmitting-receiving channel is separated into a transmitting antenna and a receiving antenna that are respectively provided with transmitting primary radiators 12a-12h and receiving primary radiators 13a-13h composed of plane array antennas arrayed retrorse to each other on a dielectric board. The respective transmitting-receiving antennas are so constituted that a plurality of adjacent ones are put in transmitting/receiving action being simultaneously selected while being shifted one by one according to the array order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar device used as a distance / speed detecting device for a vehicle-mounted collision warning device, and in particular, a plurality of adjacent beams are overlapped with each other. The present invention relates to a multi-beam radar antenna and module of the type that radiates in slightly different directions.

[0002]

2. Description of the Related Art Conventionally, as a distance / speed detecting device for a vehicle-mounted collision warning device, "radar technology" (corporate corporation)
As described in the Institute of Electronics, Information and Communication Engineers), a millimeter-wave band FM radar device is known. In this FM radar device, a transmission signal whose frequency is increased and decreased in a triangular wave shape with time is transmitted toward the front of the vehicle and the like, and a reflection signal generated by being reflected by the vehicle to be detected in front and the like is received,
This is mixed with a transmission signal to generate a beat signal, and the distance and speed to the other vehicle to be detected are detected from the frequency of the beat signal.

A patent application entitled "Radar Module and Antenna Device" relating to the applicant's prior application (Japanese Patent Application No. 7-23).
No. 9311), it has a plurality of time-division transmission / reception channels that transmit FM signals and receive reflected waves to generate beat signals, and the antennas of each transmission / reception channel are used as the primary radiators of patch array antennas. It consists of an antenna for both transmission and reception, which consists of a parabolic reflector and
A time-division type multi-beam radar module is disclosed in which a transmission system and a reception system are separated by a circulator.

That is, as shown in FIG. 11, the patch array antenna 112 is provided for every eight transmission / reception channels.
A primary radiator for transmission / reception consisting of a, 112b, 112c, ... 112h is formed on the dielectric substrate 111, and each patch array antenna and the transmission switching circuit 113 are formed.
And a receiving system between the receiving switching circuit 114 and a receiving system, the circulators 115a, 115b, 115c.
... Separation at 115h.

As shown in FIG. 12, the primary radiator for both transmission and reception is held on a holding stand 40 together with an FM radar module 110 including the same, and a substantially parabolic reflecting mirror 30 is arranged opposite to the holding stand 40. Are arranged near the focal point of.
In FIG. 11, reference numeral 116 denotes an FM signal quadrupling circuit common to each transmission / reception channel, and 117 denotes a low-noise amplifier and mixer for each reception channel.

[0006]

In the prior art radar module described with reference to FIG. 11, the antenna of each channel is shared for transmission and reception, and the transmission system and the reception system are separated by a circulator. Therefore, there is a problem that the circulator part becomes larger than the antenna part, and as a result, the miniaturization of the entire module cannot be realized. Therefore, one object of the present invention is to provide a radar antenna and module of this type that can be further miniaturized.

Further, as shown in FIG. 11, since the primary radiators are arranged in close contact with each other, interference between adjacent transmission / reception channels increases, and there is a problem that detection accuracy deteriorates. Therefore, another object of the present invention is to provide a multi-beam radar antenna and module capable of reducing interference between adjacent channels.

Further, the radiation pattern (directivity) of each patch array antenna of the above-mentioned prior art multi-beam radar module is as shown in FIG. 10 in the direction perpendicular to the dielectric substrate (vertical direction). Since the number of patches is 3, it becomes sharp to some extent. However, the radiation pattern in the plane parallel to the dielectric substrate (horizontal direction) is
As illustrated in FIG. 10, it becomes considerably wide. As a result,
There are problems that the radiation beam does not reach far away, and it is not possible to detect far, and that the azimuth resolution of each antenna decreases and the azimuth detection accuracy decreases. Further, in order to reflect the radio waves radiated from the patch array antenna without leakage, that is, in order to prevent spillover, it is necessary to widen the width of the reflecting mirror, resulting in a problem that the entire antenna becomes large. . Therefore, another object of the present invention is to provide a radar module that can realize high azimuth detection accuracy.

[0009]

According to the multi-beam radar antenna of the present invention for solving the above-mentioned problems of the prior art, the transmitting and receiving antennas of each transmitting and receiving channel are separated for transmitting and receiving. Interference between adjacent channels is reduced by providing a transmitting primary radiator and a receiving primary radiator, each of which is a planar array antenna arranged on the dielectric substrate in opposite directions. According to the radar module of the present invention, each transmission / reception channel provided with such an antenna is provided with a switching element group for performing a selective operation.

[0010]

According to an embodiment of the present invention, the transmitting primary radiator and the receiving primary radiator of each transmission / reception channel are arranged in an interdigitated manner. According to another embodiment of the present invention, the transmitting primary radiator and the receiving primary radiator of each transmission / reception channel are arranged so as to be separated from each other with a partition wall for electromagnetic shielding interposed. According to the embodiment of the radar module of the present invention, the adjacent m transmission / reception channels are simultaneously selected while being shifted one by one according to the order of arrangement, and the transmission / reception operation with high azimuth resolution is performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a multi-beam FM according to an embodiment of the present invention.
FIG. 2 is a plan view showing the configuration of a radar module, and FIG. 2 is a block diagram showing the configuration of a multi-beam FM radar device including this radar module.

Microstrip line type patch array antennas 12a, 1 are provided for each of the eight transmission / reception channels.
.. 12h for transmission, and a primary radiator for reception, which also includes patch array antennas 13a, 13b, 13c, ... Arranged on top. Each of the eight transmitting primary radiators 12a to 12h is a switching element 14a to 1 of each transmission / reception channel formed of a high electron mobility transistor (HEMT) or the like.
It is connected to the FM signal generator 23 of the main body portion 20 via each of the 4h and the common power supply line 19.

Each of the eight receiving primary radiators 13a to 13h is a mixer via a high speed switching element 15a to 15h composed of a high electron mobility transistor or the like and a common power supply line 18. It is connected to one of the 16 input terminals. An FM signal to be transmitted is supplied to the other input terminal of the mixer 16 via a common power supply line 17. The transmitting and receiving primary radiators are the same as the multi-beam FM radar module 10 shown in FIG. 1 as already described with reference to FIG. 13 in connection with the description of the prior art multi-beam FM radar device. The reflecting mirror 30 is held on a holding table 40 and arranged in the vicinity of the focal point of a generally parabolic reflecting mirror 30 arranged so as to face the holding table 40.

A defocused multi-beam antenna is formed by each of the transmitting and receiving primary radiators and a substantially parabolic reflector, and the FM emitted from each of the transmitting primary radiators 12a to 12h. After being reflected by the reflecting mirror, the signal beam is emitted in slightly different directions while the adjacent ones are partially overlapped with each other. A reflected wave generated by an object such as a vehicle follows a route opposite to that at the time of radiation and is used as a primary radiator for reception 13a to 1a.
3h, respectively, and the switching elements 15a-1
It is selected in 5h and supplied to one input terminal of the mixer 16.

The beat signal generated by the mixer 16 is supplied to the A / D conversion circuit 25 via the switching element 24 in the main body 20, converted into a digital signal and supplied to the fast Fourier transform (FFT) circuit 26. . The fast Fourier transform circuit 26 creates a frequency spectrum by performing fast Fourier transform on the beat signal converted into the digital signal, and transfers the frequency spectrum to the CPU 21. The CPU 21 detects the beat frequency from the frequency spectrum of the beat signal received from the fast Fourier transform circuit 26, and based on this, the object detected from the distance to the object causing the reflected wave, the time change rate of this distance, and the like. The relative speed of is detected and stored in the memory 27.

In parallel with the detection of the beat frequency and the detection of the object distance and the relative speed, the CPU 21 selects, via the channel control circuit 22, one of the transmission / reception channels for transmitting / receiving the FM signal. Run. The selection of the transmission / reception channels is performed such that a plurality of adjacent transmission / reception channels are simultaneously selected while being shifted one by one according to the order of arrangement.

For example, when three adjacent transmission / reception channels are simultaneously selected, as shown in FIG.
The radiation pattern in the horizontal direction of the patch array antenna composed of elements is also as sharp as the radiation pattern in the vertical direction.

In this case, as shown in the timing chart of FIG. 6, the switching element 1 of the transmission / reception channel
If the ON / OFF control signal supplied to each of 4a to 14h and 15a to 15h indicates the operation / non-operation state of the corresponding transmission / reception channel, then three adjacent eight transmission / reception channels from A to H are arranged. The three transmission / reception channels (A, B,
C), three transmission / reception channels (B, C, D), three transmission / reception channels (C, D, E), ... In this operation mode, a sharp radiation pattern is obtained also in the horizontal direction, which is the direction in which the beams are arranged, and a distant vehicle is detected with high azimuth resolution.

As shown in the timing chart of FIG. 7, the CPU 21 is, for example, shown in the timing chart of FIG. 7 when the vehicle is traveling at a low speed on a road which is congested, and when it is desired to enhance the monitoring capability in the vicinity rather than the distant monitoring function. , 8 transmit / receive channels A ~
B is operated one by one according to the order of arrangement. In this case, the radiation pattern of the beam is expanded in the horizontal direction, which is the direction in which the beams are arranged, and an obstacle or the like can be detected over a relatively wide range near the vehicle. That is, as illustrated in FIG. 8, in the high azimuth resolution operation mode, a sharp beam reaching far ahead of the host vehicle is radiated, and in the low azimuth resolution operation mode, only in the vicinity of the host vehicle, but in a relatively wide azimuth direction. The beam is emitted over a range.

As another operation example, the CPU 21 alternates and repeats a high azimuth resolution operation mode and a low azimuth resolution operation mode even during high-speed traveling, thereby performing distant monitoring and near monitoring. It is also possible to have a configuration in which the alternation is performed. In addition, as an intermediate operation form between the transmission / reception operation for every three adjacent transmission / reception channels illustrated by the timing chart of FIG. 6 and the transmission / reception operation for each single transmission / reception channel illustrated by the timing chart of FIG. It is also possible to realize an intermediate lateral resolution in which the individual transmission / reception channels are operated simultaneously. Furthermore,
It is also possible to add a module for operating each of four adjacent transmission / reception channels.

FIG. 3 is a plan view showing the structure of a multi-beam radar antenna according to another embodiment of the present invention. In this radar antenna, 16 primary radiators 12a to 12P for transmission, each of which is a patch array antenna, are used.
And 16 reception-only primary radiators 13a to 13p, each of which is also a patch array antenna, are separated from each other on the dielectric substrate 11 in opposite directions with the partition wall 9 for electromagnetic shielding interposed. It is arranged.

FIG. 4 is a block diagram showing the configuration of a multi-beam FM radar apparatus including the multi-beam radar antenna shown in FIG. In FIG. 4, the components designated by the same reference numerals as those in FIG. 2 are the same as the components already described with reference to FIG. 2, and duplicate description thereof will be omitted. In this embodiment, mixers 16a to 16p are provided for each of the 16 transmission / reception channels, and a local switching element 1 for selectively supplying local signals to these mixers.
7a to 17p are installed. The beat signal generated by the mixer of each transmission / reception channel is the intermediate frequency amplifier Aa.
After being amplified by Ap, it is supplied to the selector 28 in the main body 20.

Since the operation of the multi-beam FM radar apparatus of FIG. 4 is the same as that of the multi-beam FM radar apparatus of FIG. 2 described with reference to the timing charts of FIGS. 6 and 7, redundant description of the operation will be given. Omit it.

As described above, by arranging the primary radiator composed of the planar array antenna of the microstrip line type in the vicinity of the focus of the parabolic reflector, the transmitting antenna and the receiving antenna of each transmitting / receiving channel are formed. The radar apparatus according to the present invention has been described. However, as illustrated in the perspective view of FIG. 9, by arranging a radar module including a primary radiator composed of a microstrip line type planar array antenna near the focal point of a dielectric lens, It is also possible to employ a configuration that forms a receiving antenna.

Further, instead of the parabolic reflector, it is possible to use a curved reflector having a cylindrical shape, a hyperboloidal shape or a horn reflector shape.

Further, although the present invention has been described by taking the FM radar device as an example, the present invention can be applied to other types of multi-beam radar modules and multi-beam radar devices such as a multi-beam AM radar device.

As described in detail above, in the multi-beam radar antenna and module of the present invention, the circulator is removed by separating the transmission / reception antenna of each transmission / reception channel into the transmission-dedicated antenna and the reception-dedicated antenna. Therefore, further miniaturization is realized.

The antenna of each transmission / reception channel is provided with a primary radiator for transmission and a primary radiator for reception, which are plane array antennas arranged on the dielectric substrate in opposite directions. Therefore, interference between adjacent transmission / reception channels is reduced, and detection accuracy is improved.

Further, according to the multi-beam radar module of the present invention, a plurality of adjacent transmission / reception channels equipped with such an antenna are selectively operated while shifting one by one in the arrangement order. Since the configuration includes the switching element group, high azimuth detection accuracy can be realized.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of a multi-beam FM radar module according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a multi-beam FM radar device including the multi-beam FM radar module according to an embodiment of the present invention.

FIG. 3 is a plan view showing the configuration of a multi-beam FM radar antenna according to another embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a multi-beam FM radar device of an embodiment of the present invention including the multi-beam FM radar antenna of FIG.

FIG. 5 is a conceptual diagram showing vertical and horizontal radiation patterns of a three-element patch array antenna.

FIG. 6 is a timing chart for explaining a state in which three adjacent transmission / reception channels are sequentially operated while being shifted one by one in an arrangement order.

FIG. 7 is a timing chart for explaining how one transmission / reception channel is sequentially operated while being shifted one by one in the arrangement order.

FIG. 8 is a conceptual diagram for explaining a difference between a radiation pattern under a high azimuth decomposition operation mode and a radiation pattern under a low azimuth resolution operation mode.

9 is a perspective view showing a state in which the multi-beam FM radar module of FIG. 2 is combined with a dielectric lens.

FIG. 10 is a conceptual diagram showing vertical and horizontal radiation patterns of a one-element patch array antenna.

FIG. 11 is a plan view showing the configuration of a prior art multi-beam FM radar device.

FIG. 12 is a perspective view showing a state in which the radar module of FIGS. 1, 3, and 11 is combined with a generally parabolic reflector.

[Explanation of symbols]

10 Multi-Beam FM Radar Module 11 Dielectric Substrate 12a ~ 12p Transmit Patch Array Antenna (Primary Radiator) 13a ~ 13p Receive Patch Array Antenna (Primary Radiator) 14a ~ 14p Transmit Switching Element 15a ~ 15h Receive Switching Element 16,16a to 16p Mixer 17a to 17p Local switching element 20 Main body 21 CPU 22 Channel control circuit 23 FM signal generation circuit 26 Fast Fourier transform circuit (FFT)

Claims (6)

[Claims] 1. A multi-beam comprising a plurality of transmission / reception channels for transmitting a beam of a high frequency signal and receiving a reflected wave thereof.
An antenna of a radar device, wherein the transmission / reception antennas of each transmission / reception channel are separated into a transmission antenna and a reception antenna, each of which is composed of a planar array antenna arranged in opposite directions on a dielectric substrate for transmission. A multi-beam radar antenna comprising a primary radiator and a receiving primary radiator. 2. The multi-beam radar according to claim 1, wherein the transmitting primary radiator and the receiving primary radiator of the transmission / reception antennas of the respective transmission / reception channels are arranged in an interdigitated manner. antenna. 3. The transmitting / receiving primary radiator of the transmitting / receiving antenna of each transmitting / receiving channel according to claim 2, wherein the transmitting / receiving primary radiator is arranged with a partition wall for electromagnetic shielding interposed therebetween. Characteristic multi-beam radar antenna. 4. A multi-beam comprising a plurality of transmission / reception channels for transmitting a beam of a high frequency signal and receiving a reflected wave thereof.
A module of a radar device, which is a transmission / reception antenna for each transmission / reception channel separated for transmission and reception, each of which consists of a planar array antenna arrayed in opposite directions on a dielectric substrate. A multi-beam radar module comprising: a primary radiator and a primary radiator for reception; and a switching element group for selectively operating each of the transmission / reception channels. 5. The transmission / reception channel according to claim 4, wherein the number of the transmission / reception channels is n (n is a natural number of 3 or more), and the number of adjacent m (m is a natural number smaller than n) is shifted one by one according to the order of arrangement. The multi-beam radar module is characterized in that it simultaneously selects and performs transmitting and receiving operations. 6. The high frequency signal according to claim 4, wherein the high frequency signal is an FM signal whose frequency is changed with time, and further comprising a frequency mixer that mixes the reception signal with a transmission component to generate a beat signal. A multi-beam radar module characterized by