MOBILE RADAR AND PLANAR ANTENNA

• US 20090267822A1
• Filed: 04/12/2009
• Published: 10/29/2009
• Est. Priority Date: 04/28/2008
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: MORINAGA, Mitsutoshi, SHINODA, Hiroshi
• Granted Patent: US 8,009,082 B2
• Time in Patent Office: Days
• US Class Current: 342/70
• CPC Class Codes: G01S 13/34 using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/4454 phase comparisons monopulse, i.e. comparing the echo signals received by an interferometric antenna arrangement
• CPC Class Codes: G01S 13/4463 using phased arrays
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/0263 Passive array antenna
• CPC Class Codes: G01S 2013/9321 Velocity regulation, e.g. cruise control
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 3/74 Multi-channel systems specially adapted for direction-finding, i.e. having a single antenna system capable of giving simultaneous indications of the directions of different signals systems in which the directions of different signals are determined sequentially and displayed simultaneously G01S3/04, G01S3/14
• CPC Class Codes: G01S 7/2813 Means providing a modification of the radiation pattern for cancelling noise, clutter or interfering signals, e.g. side lobe suppression, side lobe blanking, null-steering arrays specially adapted to secondary radar systems G01S13/762; aerials or aerials systems H01Q21/29, H01Q25/00
• CPC Class Codes: G01S 7/352 Receivers
• CPC Class Codes: G01S 7/356 involving particularities of FFT processing
• CPC Class Codes: G01S 7/4017 of HF systems
• CPC Class Codes: G01S 7/4021 of receivers
• CPC Class Codes: G01S 7/403 in azimuth, i.e. in the horizontal plane
• CPC Class Codes: G01S 7/4056 specially adapted to FMCW
• CPC Class Codes: G01S 7/4091 during normal radar operation
• CPC Class Codes: H01Q 3/2635 the auxiliary unit being composed of a plurality of antennas

Abstract

In a conventional automotive radar, a return occurs in a phase difference characteristic necessary for a super-resolution method, resulting in an increase of a detection error, or an extremely narrowed azimuth detection range. A transmitting array antenna, and receiving array antennas are composed of antenna elements respectively, and aligned in a horizontal direction. The weighting of receiving sensitivities of the antenna elements of the receiving array antenna 1 is A1, A2, A3, and A4, which are monotonically decreased from an inner side toward an outer side as represented by A1≧A2≧A3≧A4. On the other hand, the receiving array antenna 3 is symmetrical with the receiving array antenna with respect to the receiving array antenna 1.

Claims

1. A mobile radar comprising:

a planar antenna; and

a transmitter-receiver unit,

wherein the planar antenna includes at least one transmitting array antenna and three or more receiving array antennas,

wherein the three or more receiving array antennas are aligned in a horizontal direction,

wherein the receiving array antennas has the number of antenna elements of the receiving array antennas positioned at both outer ends thereof which are aligned in the horizontal direction which is larger than the number of antenna elements of the other at least one receiving array antenna positioned at inner side in the horizontal direction,

wherein an outermost antenna element is smaller than an innermost antenna element in the weighting of the receiving sensitivity of the receiving antennas located at both outer ends thereof in the horizontal direction, and

wherein the respective receive signals obtained by reflecting a radio wave transmitted from the transmitting array antenna by at least one obstacle and received by the respective receiving array antennas are synthesized in directivity after being weighted in the amplitude/phase, and an azimuth angle being null or low sensitivity is scanned to specify azimuth orientation of the at least one obstacle.

2. The mobile radar according to claim 1,

wherein the weighting of the receiving sensitivity of the receiving array antennas at the both outer ends in the horizontal direction is monotonically decreased from the innermost antennal element to the outermost antenna element.

3. The mobile radar according to claim 1,

wherein an odd number of receiving array antennas are aligned in the horizontal direction, and

wherein when the receiving array antennas are divided into two groups of right side and left side with a receiving array antenna located in the center as a boundary, the outermost antenna element is smaller than the innermost antenna element in the weighting of a receiving sensitivity of the receiving array antennas located at both outer ends thereof in the horizontal direction.

4. The mobile radar according to claim 1,

wherein an even number of the receiving array antennas are aligned in the horizontal direction, and

wherein when the receiving array antennas are divided into two groups of right side and left side with a boundary provided between two receiving array antennas located on a center side thereof, the outermost antenna element is smaller than the innermost antenna element in the weighting of a receiving sensitivity of the respective groups in the horizontal direction.

5. The mobile radar according to claim 4,

wherein the weighting of the receiving sensitivity of the respective groups in the horizontal direction is monotonically decreased from the innermost antennal element to the outermost antenna element.

6. The mobile radar according to claim 1,

wherein the weighting of the receiving sensitivity of the receiving array antennas is conducted by an electric power distributor configured by a transmission line on the same dielectric substrate as the receiving array antennas.

7. The mobile radar according to claim 6,

wherein each of the antenna elements includes a plurality of patch elements formed on a dielectric substrate, and a feed micro-strip line connected to the respective patch elements, and

wherein the weighting of the receiving sensitivity of the receiving array antennas is conducted by a difference in a width of the micro-strip line corresponding to the respective patch elements.

8. The mobile radar according to claim 1,

wherein the respective antenna elements are configured as an element line in which the antenna elements are arrayed in a vertical direction on a common dielectric substrate.

9. The mobile radar according to claim 1,

wherein the weighting of the receiving sensitivity of the receiving array antennas is conducted by a difference in a planar size between the antenna elements.

10. The mobile radar according to claim 1,

wherein the number of antenna elements that are grouped according to directivity synthesis of the receive signals from the plurality of receiving array antennas by a transmitter-receiver unit is selectable, and

wherein the number of grouped antenna elements is configured such that the number of elements in a group including the antenna elements of the receiving array antennas located at both outer ends thereof which are arranged in the horizontal direction is larger than the number of elements in a group including the antenna elements of the other receiving array antennas positioned at inner side in the horizontal direction.

11. A mobile radar comprising:

a planar antenna disposed on a common ground plate; and

a transmitter-receiver unit disposed on the common ground plate,

wherein the planar antenna includes at least one transmitting array antenna, and a plurality of receiving array antennas,

wherein each of the receiving antennas includes three or more antenna elements aligned in a horizontal direction,

wherein the receiving array antennas are configured such that the number of antenna elements of the receiving array antennas located at both outer ends thereof which are arranged in the horizontal direction is larger than the number of antenna elements of the other receiving array antennas positioned at inner side in the horizontal direction, and

wherein at least one pair of the receiving array antennas is configured such that an outermost antenna element is smaller than an innermost antenna element in the weighting of the receiving sensitivity in the horizontal direction.

12. The mobile radar according to claim 11,

wherein the planar antenna is disposed on one surface of the ground plate, and the transmitter-receiver unit is disposed on another surface thereof, and

wherein the weighting of the receiving sensitivity of the receiving array antennas is conducted by an electric power distributor configured by a transmission line on the same dielectric substrate as the receiving array antennas.

13. The mobile radar according to claim 11,

wherein the planar antenna and the transmitter-receiver unit are integrated on the same substrate on the same surface of the ground plate into a single or a plurality of MMIC chips, and

wherein the weighting of the receiving sensitivity is conducted by an electric power distribution micro-strip line.

14. A planar antenna comprising:

at least one transmitting array antenna; and

three or more receiving array antennas,

wherein the receiving array antennas are arranged on a common dielectric substrate in a horizontal direction,

wherein each of the receiving array antennas is configured as an element train in which a plurality of antenna elements are arrayed in a vertical direction,

wherein the number of antenna elements of the receiving array antennas at both outer ends thereof which are arranged in a horizontal direction is larger than the number of antenna elements of the other at least one receiving array antenna positioned at inner side in the horizontal direction, and

wherein an outermost antenna element is smaller than an innermost antenna element in the weighting of the receiving sensitivity of the receiving array antennas located at the both outer ends.

15. The planar antenna according to claim 14,

wherein the weighting of the receiving sensitivity of the receiving array antennas at the both outer ends in the horizontal direction is monotonically decreased from the innermost antennal element to the outermost antenna element.

16. The planar antenna according to claim 14,

wherein an odd number of receiving array antennas are aligned in the horizontal direction, and

wherein the outermost antenna element is smaller than the innermost antenna element in the weighting of the receiving sensitivity of the receiving array antennas at both outer ends thereof in the horizontal direction.

17. The planar antenna according to claim 14,

wherein an even number of the receiving array antennas are aligned in the horizontal direction, and

wherein when the receiving array antennas are divided into two groups of right side and left side with a boundary provided between two receiving array antennas located on a center side thereof, the outermost antenna element is smaller than the innermost antenna element in the weighting of a receiving sensitivity of the respective groups in the horizontal direction.

18. The planar antenna according to claim 14,

wherein the weighting of the receiving sensitivity of the receiving array antennas is conducted by an electric power distributor configured by a transmission line on the same dielectric substrate as the receiving array antennas.

19. The planar antenna according to claim 14,

wherein each of the antenna elements includes a plurality of patch elements formed on a dielectric substrate, and a feed micro-strip line connected to the respective patch elements, and

wherein the weighting of the receiving sensitivity of the receiving array antennas is conducted by a difference in a width of the micro-strip line corresponding to the respective patch elements.

20. The planar antenna according to claim 14,

wherein the weighting of the receiving sensitivity of the receiving array antennas is conducted by a difference in a planar size between the antenna elements.