Built-in radiation structure for a millimeter wave radar sensor

• US 5,512,901 A
• Filed: 09/07/1993
• Issued: 04/30/1996
• Est. Priority Date: 09/30/1991
• Status: Expired due to Term

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Tsou, Hsi-Shen E., Chen, Chun-Hong H.
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US08/117,266
• Time in Patent Office: 966 Days
• Field of Search: 342/175, 342/70, 342/200, 342/27, 343/700 MS
• US Class Current: 342/175
• CPC Class Codes: G01S 13/345 using triangular modulation
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/0263 Passive array antenna
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 2013/9321 Velocity regulation, e.g. cruise control
• CPC Class Codes: G01S 2013/93272 in the back of the vehicles
• CPC Class Codes: G01S 2013/93274 on the side of the vehicles
• CPC Class Codes: G01S 2013/93275 in the bumper area
• CPC Class Codes: G01S 2013/93277 in the lights
• CPC Class Codes: G01S 7/032 Constructional details for solid-state radar subsystems
• CPC Class Codes: G01S 7/2883 using FFT processing
• CPC Class Codes: H01Q 1/3233 particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems
• CPC Class Codes: H01Q 13/10 Resonant slot antennas
• CPC Class Codes: H01Q 15/0013 said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective

Abstract

A compact radar system includes a dielectric substrate having an upper and lower surface. A ground plane is formed on the upper surface of the dielectric substrate and includes a radiating slot formed therein. A radar transceiver is located below the dielectric substrate and generates transmit signals. A frequency selective surface spaced above the dielectric substrate includes a radiating aperture with a plurality of uniformly spaced holes. The frequency selective surface decreases flow of electromagnetic energy from the radiating slot in one direction towards the transceiver and increases the flow of electromagnetic radiation in an opposite direction away from the transceiver.

Claims

1. A compact radar system including:

a dielectric substrate having an upper and lower surface;

a ground plane formed on the upper surface of the dielectric substrate and including a radiating slot formed therein;

radar transceiver means located adjacent the lower surface of the dielectric substrate for generating transmit signals; and

a frequency selective surface spaced above said dielectric substrate and said radiating slot and including a radiating aperture with and array of uniformly spaced holes, wherein said frequency selective surface decreases flow of electromagnetic energy from said radiating slot in one direction towards said transceiver means and increases said flow of electromagnetic radiation in an opposite direction away from said transceiver means.

2. The compact radar system of claim 1 wherein said ground plane further includes a receiving slot formed therein, said radar transceiver receives reflected signals, and said frequency selective surface includes a receiving aperture including a plurality of spaced holes.

3. The compact radar system of claim 1 wherein said plurality of spaced holes are cross-shaped.

4. The compact radar system of claim 1 wherein said plurality of spaced holes are Jerusalem cross-shaped.

5. The compact radar system of claim 1 wherein said plurality of spaced holes are circular.

6. The compact radar system of claim 1 wherein said plurality of spaced holes are tripole-shaped.

7. The compact radar system of claim 1 wherein said plurality of spaced holes are dipole-shaped.

8. The compact radar system of claim 1 wherein said plurality of spaced holes are rectangular.

9. The compact radar system of claim 1 wherein said radiating aperture is substantially square-shaped.

10. The compact radar system of claim 9 wherein said radiating slot is aligned with a diagonal of said square-shaped radiating aperture.

11. The compact radar system of claim 2 wherein said receiving aperture is substantially square-shaped.

12. The compact radar system of claim 11 wherein said receiving slot is aligned with a diagonal of said square-shaped receiving aperture.

13. The compact radar system of claim 1 further including an upper and lower housing for enclosing said radar system.

14. The compact radar system of claim 1 wherein the radar transceiver means includes radiating and receiving microstrip feedlines connected to the radiating and receiving slots.

15. The compact radar system of claim 12 wherein the microstrip feedlines are formed on the lower surface of the dielectric substrate.

16. The compact radar system of claim 12 wherein the radar system further includes a digital signal processing circuit located between the dielectric substrate and the lower housing.

17. The compact radar system of claim 1 wherein the radar system further includes means for spacing the frequency selective surface above the ground plane.

18. The compact radar system of claim 14 wherein the radiating aperture of the frequency selective surface substantially matches an impedance of the radiating microstrip feedline.

19. The compact radar system of claim 14 wherein the receiving aperture of the frequency selective surface matches an impedance of the receiving microstrip feedline.

20. The compact radar system of claim 13 wherein said upper housing is formed by a radome connected to a spacer.

21. The compact radar system of claim 20 wherein the spacer is formed by a plate including radiating and receiving holes which are aligned with the radiating and receiving apertures on the frequency selective surface when assembled.

22. The compact radar system of claim 1 further including an IF/modulator circuit located below said dielectric substrate.

23. The compact radar system of claim 22 wherein the IF/modulator circuit and the transceiver means are fabricated on the lower surface of the dielectric substrate.

24. The compact radar system of claim 1 wherein the compact radar system is incorporated into a tail light of a vehicle.

25. The compact radar system of claim 1 wherein the compact radar system is incorporated into a side mirror of a vehicle.

26. A compact radar system including:

an upper housing with a radome connected to a spacer;

a lower housing;

a dielectric substrate having an upper and lower surface;

a ground plane formed on the upper surface of the dielectric substrate and including a radiating slot and a receiving slot formed therein;

radar transceiver means located adjacent the lower surface of the dielectric substrate for generating transmit signals and for receiving reflected transmit signals, wherein said transceiver includes radiating and receiving microstrip feedlines connected to the radiating and receiving slots;

a frequency selective surface spaced above the upper surface of said dielectric substrate and said radiating slot and said receiving slot and including a receiving aperture and a radiating aperture each with an array of spaced holes, wherein said frequency selective surface decreases flow of electromagnetic energy from said radiating slot in one direction towards said transceiver means and increases said flow of electromagnetic radiation in an opposite direction away from said transceiver means, and wherein the frequency selective surface matches an impedance of the radiating and receiving microstrip feedlines;

means for spacing the frequency selective surface above the ground plane; and

a digital signal processing circuit located between the dielectric substrate and the lower housing.

27. The radar system of claim 26 wherein the radar transceiver means is fabricated on the lower surface of the dielectric substrate.

28. The compact radar system of claim 26 wherein the spacer is formed by a plate including radiating and receiving portions which are aligned with the radiating and receiving apertures on the frequency selective surface when assembled.

29. The compact radar system of claim 28 wherein at least one of the radiating and receiving apertures are substantially square and at least one of the radiating and receiving slots are formed partially along a diagonal of said at least one of the radiating and receiving apertures.

30. The compact radar system of claim 26 further including an IF/modulator circuit located below the lower surface of said dielectric substrate.

31. The compact radar system of claim 28 wherein the IF/modulator circuit and the transceiver means are fabricated on the lower surface of the dielectric substrate.

32. The compact radar system of claim 26 wherein the compact radar system is incorporated into a tail light of a vehicle.

33. The compact radar system of claim 26 wherein the compact radar system is incorporated into a side mirror of a vehicle.

34. A compact radar system including:

an upper housing with a radome connected to a spacer;

a lower housing;

a dielectric substrate having an upper and lower surface;

a ground plane formed on the upper surface of the dielectric substrate and including a radiating slot and a receiving slot formed therein;

radar transceiver means for generating transmit signals and for receiving reflected signals, wherein said transceiver includes radiating and receiving microstrip feedlines connected to the radiating and receiving slots;

a frequency selective surface spaced above said dielectric substrate and said radiating and receiving slots and including a receiving aperture and a radiating aperture each with an array of spaced holes, wherein said frequency selective surface decreases flow of electromagnetic energy from said radiating slot in one direction towards said transceiver means and increases said flow of electromagnetic radiation in an opposite direction away from said transceiver means,

wherein at least one of the radiating and receiving apertures are substantially square and at least one of the radiating and receiving slots are formed partially along a diagonal of said at least one of the radiating and receiving apertures, and wherein the frequency selective surface matches an impedance of the radiating microstrip feedlines;

means for spacing the frequency selective surface above the ground plane, wherein the spacing means is formed by a plate including radiating and receiving portions which are aligned with the receive and transmit apertures on the frequency selective surface when assembled;

a digital signal processing circuit located between the dielectric substrate and the lower housing; and

an IF/modulator circuit fabricated on the lower surface of the dielectric substrate.

35. The compact radar system of claim 34 wherein the compact radar system is incorporated into a tail light of a vehicle.

36. The compact radar system of claim 34 wherein the compact radar system is incorporated into a side mirror of a vehicle.