Millimeter wave-radar and method for manufacturing the same

• US 20040227663A1
• Filed: 02/24/2004
• Published: 11/18/2004
• Est. Priority Date: 03/24/2003
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takano, Kazuaki, Suzuki, Mitsushige
• Granted Patent: US 7,126,525 B2
• Time in Patent Office: Days
• US Class Current: 342/70
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/93275 in the bumper area
• CPC Class Codes: G01S 7/03 Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
• 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: H01Q 1/42 Housings not intimately mechanically associated with radiating elements, e.g. radome
• CPC Class Codes: H01Q 17/001 for modifying the directional characteristic of an aerial

Abstract

A millimeter-wave radar has a radome or radar cover including a layer, the dielectric constant of which is a greater than that of the other portion without the layer, or including a magnetic loss layer in an appropriate position with respect to the antenna. The dielectric constant of the radome or radar cover can be made higher in a portion corresponding to the side of the antenna than in a portion corresponding to the front of the antenna.

Claims

1. A millimeter-wave radar comprising:

an antenna base having a transmission/reception antenna;

a housing fixing the antenna base; and

at least a radome or a radar cover enclosing the antenna base;

wherein the radome or the radar cover is provided with a radio wave absorbing layer.

2. A millimeter-wave radar according to claim 1, wherein the radio wave absorbing layer is provided to a side surface of the radome or the radar cover.

3. A millimeter-wave radar according to claim 1, wherein the radio wave absorbing layer has its performance adjusted according to its position with respect to the transmission/reception antenna.

4. A millimeter-wave radar according to claim 1, wherein the radio wave absorbing layer has a higher dielectric loss than that of a material of the radome or the radar cover.

5. A millimeter-wave radar according to claim 1, wherein the radio wave absorbing layer is a magnetic loss layer.

6. A millimeter-wave radar according to claim 1, wherein the radio wave absorbing layer has a higher dielectric constant than that of a material of the radome or the radar cover.

7. A millimeter-wave radar according to claim 1, wherein the radome and the radar cover use a material with a dielectric constant of 3.0 or lower in a portion thereof corresponding to a front of the transmission/reception antenna.

8. A millimeter wave-radar according to claim 1, wherein the radome and the radar cover use, as a main ingredient in a portion thereof corresponding to a front of the transmission/reception antenna, at least one of polycarbonate, syndiotactic polystyrene, polypropylene and a combination of these materials as a main ingredient and ABS.

9. A millimeter wave-radar according to claim 1, wherein the radio wave absorbing layer is formed of only a layer having a predetermined angle to a surface of the transmission/reception antenna or of a combination of the layer having the predetermined angle and a layer having a predetermined angle to a normal of the surface of the transmission/reception antenna.

10. A millimeter wave-radar according to claim 1, wherein the radio wave absorbing layer is a mesh of less than ¼

of wavelength.

11. A millimeter wave-radar according to claim 1, wherein the radio wave absorbing layer includes at least one of carbon nanotube, carbon microcoil, shungite carbon, carbon black, expanded graphite, carbon fiber and hexagonal ferrite.

12. A millimeter wave-radar comprising:

an antenna base having a transmission/reception antenna;

a housing fixing the antenna base; and

at least a radome or a radar cover enclosing the antenna base;

wherein the radome or the radar cover has a greater dielectric constant in a portion thereof corresponding to a side of the transmission/reception antenna than in a portion thereof corresponding to a front of the antenna.

13. A millimeter wave-radar according to claim 12, wherein the radome and the radar cover use in a portion thereof corresponding to a front of the transmission/reception antenna a material with a dielectric constant of 3.0 or lower.

14. A millimeter wave-radar according to claim 12, wherein the radome and the radar cover use, as a main ingredient in a portion thereof corresponding to a front of the transmission/reception antenna, at least one of polycarbonate, syndiotactic polystyrene, polypropylene and a combination of these materials as a main ingredient and ABS.

15. A millimeter wave-radar comprising:

an antenna base having a transmission/reception antenna;

a housing fixing the antenna base; and

at least a radome or a radar cover enclosing the antenna base;

wherein the radome or the radar cover has a dielectric constant which progressively increases from a front of the transmission/reception antenna toward a side of the antenna.

16. A millimeter wave-radar according to claim 15, wherein the radome and the radar cover use in a portion thereof corresponding to a front of the transmission/reception antenna a material with a dielectric constant of 3.0 or lower.

17. A millimeter wave-radar according to claim 15, wherein the radome and the radar cover use, as a main ingredient in a portion thereof corresponding to a front of the transmission/reception antenna, at least one of polycarbonate, syndiotactic polystyrene, polypropylene and a combination of these materials as a main ingredient and ABS.

18. A method of manufacturing a millimeter wave-radar, wherein the millimeter wave-radar comprises an antenna base having a transmission/reception antenna, a housing fixing the antenna base, and at least a radome enclosing the antenna base or a radar cover enclosing the radome;

the manufacturing method integrally forming into a one-piece structure the radome or radar cover and a radio wave absorbing layer through an insert molding or double molding process.

19. A method of manufacturing a millimeter wave-radar, wherein the millimeter wave-radar comprises an antenna base having a transmission/reception antenna, a housing fixing the antenna base, and at least a radome enclosing the antenna base or a radar cover enclosing the radome;

the manufacturing method integrally forming into a one-piece structure through an insert molding or double molding process, materials having different dielectric constants and forming the radome or radar cover.