JPH0897620A - Multi-beam planar array antenna - Google Patents

Abstract

PURPOSE: To provide an antenna capable off scanning with a simple configuration and manufactured inexpensively. CONSTITUTION: The antenna is provided with plural patches P11-P14 arranged on a dielectric board DB, a feeding section P, and feeder lines S0-S4 interconnecting the patches P11-P44. The plural patches P11-P44 form plural antenna parts A1-A4 emitting a beam with a different tilt angle set based on the difference from the feeding line length of them. The feeder lines S0-S4 are provided with feeding selection means D1-D4, V0-V4, F0-F4 used to selectively start/stop the feeding to each of the plural antenna parts A0-A4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-beam planar array antenna used as a component of an on-vehicle radar device, and more particularly to a multi-beam planar array antenna having a simple and inexpensive beam scanning function. It is about.

[0002]

2. Description of the Related Art Conventionally, a vehicle-mounted radar device that utilizes millimeter-wave radio waves has been developed. Conventionally, in order to scan a beam with such an on-vehicle radar device, as disclosed in Japanese Patent Application No. 3-74758 related to the applicant's prior application, an offset defocus parabolic multi-beam antenna, etc. Was using.

[0003]

In the conventional scanning method using the above offset / defocus / parabolic / multi-beam antenna, the antenna structure is complicated and the manufacturing cost is high, and the cost of the entire radar apparatus is increased. There is a problem that it is one of the causes. Therefore, an object of the present invention is to provide a scannable antenna which has a simple structure and can be manufactured at low cost.

[0004]

A multi-beam planar array antenna according to the present invention comprises a plurality of patches arranged on a dielectric substrate, a feeding section, and a feeding line connecting between the feeding section and each patch. It is composed of a planar antenna provided with. The plurality of patches form a plurality of antenna portions that radiate beams with different tilt angles set based on the difference in the feed line length for each patch. The power feeding line includes a power feeding selecting unit that selectively starts and stops power feeding to each of the plurality of antenna portions.

[0005]

As shown in FIG. 5, two patches P1 and P2 are formed on the dielectric substrate DB, and the patches P1 and P2 are respectively provided from the feeding point FP through feeding lines F1 and F2 having different lengths. Supply high frequency power. Radio waves radiated from the patches P1 and P2 are fed from the feeding point FP to feeding lines F1 and F2.
They strengthen each other in the direction in which the total phase difference along the propagation path in the space is equal to each other, and cancel each other out in other directions. Therefore, the patches P1 and P2 are radiated in a direction inclined by the tilt angle θ from the normal line (one-dot chain line in the figure) set up. According to the present invention, a plurality of antenna portions having different tilt angles are formed on a dielectric substrate, and one or some of them are selectively operated by a diode or the like to perform beam scanning.

[0006]

1 is a plan view showing the structure of a multi-beam planar array antenna according to an embodiment of the present invention. On the dielectric substrate DB, 16 rectangular patches P11 to P44 are provided.
Are arranged. A power feeding portion P is formed at the center of the dielectric substrate DB. Microstrip type power supply lines S0 and S1 for connecting between the power supply unit P and each patch.
To S4 are formed on the dielectric substrate PB. The 16 patches P11 to P14 form four antenna portions A1, A2, A3, A4 that radiate beams with different tilt angles set based on the difference in the feed line lengths for the respective patches.

The antenna portion A1 has two left-side patches P11 and P12 having the same feed line length and two right-side patches P13 and P13 having a feed line length L1 longer than these.
P14 and. The antenna portion A2 includes two left patches P21 and P22 having the same feed line length.
And the length of the feeder line is L2 longer than these
It is composed of individual patches P23 and P24.

The antenna portion A3 includes two right-side patches P31 and P32 having the same feed line length and two left-side patches P33 and P33 having a feed line length L3 longer than these patches P31 and P32.
And P34. The antenna part A4 includes two right patches P41 and P42 having the same feed line length.
And the length of the feeder line is L4 longer than these
It is composed of individual patches P43 and P44.

A power feeding portion P formed in the central portion of the dielectric substrate
Is composed of a coaxial line connector arranged on the back surface and pins extending from inside the waveguide, and performs mode conversion from the coaxial mode or the waveguide mode to the microstrip mode. Since the power feeding portion P is arranged in the central portion of the dielectric substrate in this manner, it is possible to arrange the elements at a higher density than in the case where power is fed from the peripheral portion.

Power feeding from the power feeding portion P to the antenna portion A1 is performed through the microstrip type power feeding lines S0 and S1, and power feeding from the power feeding portion P to the antenna portion A2 is performed through the power feeding lines S0 and S2. Power feeding from the power feeding portion P to the antenna portion A3 is performed through the power feeding lines S0 and S3, and power feeding from the power feeding portion P to the antenna portion A4 is performed through the power feeding lines S0 and S4.

A PIN diode D having excellent high frequency characteristics is provided between the feed line S0 and each of the feed lines S1 to S4.
1, D2, D3, D4 are installed. The bias circuit for each PIN diode has a bias input terminal V
0, V1 to V4 and low pass filters F0, F1 to F4
And is formed on the dielectric substrate DB. That is, the common bias input terminal V0 is always applied with a positive voltage, and each of the bias input terminals V1 to V4 has a positive voltage higher than the positive voltage applied to the terminal V0 and a ground (zero) voltage. Either of these is selectively applied. When the ground voltage is applied to the bias input terminals V1 to V4, the corresponding PIN diodes D1 to D4 become conductive to electrically connect the power supply line S0 and the corresponding power supply lines S1 to S4, and the power supply unit P responds. The harmonic power is supplied to the antenna units A1 to A4.

Since the antenna parts A1 to A4 have different tilt angles, as shown in FIG.
Beams B1 to B4 directed in different kinds of directions are emitted. Therefore, four PIN diodes D1, D2, D
By conducting one of the antennas 3, 3 and D4 in the same order for a predetermined period of time, the beams B1, B2, B3, B from one of the four antenna units A1, A2, A3, A4 in the same order for a predetermined period of time.
When one of the antennas 4 is radiated in the same order and the reflected wave generated by the object is propagated to the feeding portion P through the opposite path, the plane array antenna scans the beam in four different directions.

An example of an on-vehicle radar including the multi-beam planar array antenna of this embodiment shown in FIG. 1 is shown in a block diagram of FIG. Four radar modules LM1 including the multi-beam planar array antenna PA of the above embodiment
To LM4, and a processing block PS for controlling the operation of each of these radar modules and processing a signal containing information on an obstacle to issue an alarm.

Each of the radar modules LM1 to LM4, as represented by the radar module LM1, is a transmission / reception unit TR including an FM signal generator M1, a signal delay unit including a delay circuit M5, and four antenna parts. A1-
It is composed of a multi-beam planar array antenna unit PA including A4. Radar modules LM1 to LM4
As shown in the conceptual diagram of FIG. 4, each of the above is installed at four corners of the vehicle, and the processing section PS is installed at an appropriate place in the vehicle.

The FM signal generator M1 generates an FM signal whose frequency changes in a sawtooth shape in a predetermined cycle in synchronization with the timing control signal received from the timing control circuit P3 of the processing section PS. A part of the generated FM signal is supplied to the multi-beam planar array antenna PA via the directional coupler (coupler), the amplifier M3 and the circulator M4, and is turned on based on the control signal received from the timing control circuit P3 of the processing unit PS. / PIN diodes D1 to D4 that are turned off
Is radiated to the outside of the vehicle from one of the corresponding antenna parts A1 to A4. The FM signal radiated from the antenna portion and reflected by the object outside the vehicle is received by the corresponding antenna portion and is supplied to one input terminal of the mixer M4 through the delay circuit M5 and the circulator M4.

At the other terminal of the mixer M4, a part of the FM signal generated by the FM signal generator M1 is connected to the coupler M.
It has been supplied through 2. Therefore, the mixer M4
It outputs a beat signal having a frequency that increases according to the distance to the object that caused the reflection. This beat signal is supplied to the processing unit PS, passes through the selector P5 and the A / D conversion circuit P.
6 and is converted into a digital signal. The beat signal converted into a digital signal is decomposed into a frequency spectrum in a fast Fourier transform circuit (FFT) P7. The processing unit P1 detects obstacle information by analyzing the beat signal which is decomposed into a frequency spectrum, and displays the information on the display device.

The case where the tilt angle is set in the left-right direction has been exemplified above. However, it is also possible to set the tilt angle in the front-rear direction, or to set the tilt angle in which the left-right direction and the front-rear direction are combined.

Further, the case where each antenna section is composed of four patches has been illustrated. However, if necessary, for example, in order to sharpen the directivity, each antenna unit may be composed of an appropriate number of patches larger than four.

Further, the application to beam scanning in which the radio wave is radiated from only one of the plurality of antenna parts has been described. However, it is also applicable to change the combined directivity of beams by simultaneously radiating radio waves from any two or more of these.

[0020]

As described above in detail, in the multi-beam planar array antenna of the present invention, a plurality of antenna parts having different tilt angles are formed in advance, and a desired one of them is a PIN diode. Since the configuration is such that it is selectively operated by on / off control, it is possible to achieve beam scanning and the like with an extremely simple and inexpensive configuration.

In particular, the multi-beam planar array antenna of the present invention exhibits the advantages of downsizing and cost reduction when it is applied to an on-vehicle radar device for detecting an obstacle at a short distance.

[Brief description of drawings]

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

FIG. 2 is a conceptual diagram showing an example of beam patterns B1 to B4 of radio waves radiated from each of the antenna parts A1 to A4 in the above embodiment.

3 is a block diagram showing an example of the configuration of an on-vehicle radar device including the multi-beam planar array antenna of the embodiment of FIG.

FIG. 4 is a conceptual diagram showing an example of an arrangement and beam patterns of four radar modules LM1 to LM4 included in the vehicle-mounted radar device of FIG.

FIG. 5 is a conceptual diagram for explaining the operation of the present invention.

[Explanation of symbols]

 DB Dielectric substrate P11 to P44 Patch A1 to A4 Antenna part P Feeding part S0 to S4 Feeding line D1 to D4 PIN diode V0 to V4 Bias voltage input terminal F0 to F4 Low pass filter

Claims (3)

[Claims] 1. A planar array antenna comprising a plurality of patches arranged on a dielectric substrate, a power feeding section, and a power feeding line connecting the power feeding section and each of the patches, wherein the plurality of patches are provided. Form a plurality of antenna portions that radiate beams with different tilt angles set based on the difference in the lengths of the feed lines with respect to each, and the feed line selectively feeds power to each of the plurality of antenna portions. A multi-beam planar array antenna, characterized in that it is provided with a power supply selecting means for starting and stopping. 2. The planar array antenna according to claim 1, wherein the feeding selection means is a diode or a transistor that is selectively made conductive. 3. The planar array according to claim 1, wherein the power feeding portion is formed so as to penetrate the dielectric substrate from a back surface to a front surface in a central portion of the dielectric substrate. antenna.