Short-range doppler radar

• US 4,319,244 A
• Filed: 01/17/1980
• Issued: 03/09/1982
• Est. Priority Date: 01/22/1979
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd., Nissan Motor Co., Ltd.
• Original Assignee: Hitachi, Ltd., Nissan Motor Co., Ltd.
• Inventors: Sekine, Kenji, Endo, Akira, Hirota, Yukitsugu, Kimura, Katsuhiro, Kaneko, Yoichi
• Primary Examiner(s): Tubbesing, T. H.
• Application Number:
  US06/112,744
• Time in Patent Office: 782 Days
• Field of Search: 343/8, 343/5 DD, 343/5 HM, 343/ 5 TM
• US Class Current: 342/104
• CPC Class Codes: G01S 13/92 for velocity measurement
• CPC Class Codes: G01S 7/032 Constructional details for solid-state radar subsystems

Abstract

In a Doppler radar system for measuring the velocity of a vehicle, such as an automobile, in order to lessen interference with external electric wave appliances, such as radios and televisions, caused by transmitting microwaves, one of the higher harmonics generated from a mixer diode driven by the fundamental waves of a local oscillator is selected by a filter for transmission and is used as the transmission output wave, whereby the power of the transmission waves is remarkably reduced in comparison with the mixer driving power.

Claims

1. A short-range Doppler radar comprising:

(a) an oscillator;

(b) a frequency multiplier device which is driven by an output of said oscillator and which forms a range of higher harmonic frequency components of a frequency of the oscillator output;

(c) filter means for selecting one of the higher harmonic frequency components formed by said frequency multiplier device;

(d) means for radiating the selected higher harmonic frequency component provided at the output of said filter means and for receiving reflected waves of the radiated component; and

(e) means for detecting the Doppler frequency in the received reflected waves.

2. A short-range Doppler radar according to claim 1, wherein a dielectric substrate which forms a micro-integrated circuit including said frequency multiplier device and a micro strip line for coupling the output of said oscillator to said frequency multiplier device is mounted on an inner wall of a metallic package, and said filter means is made up of a window provided in said dielectric substrate and the adjacent wall of said metallic package and a waveguide coupling said window and said radiating means.

3. A short-range Doppler radar according to claims 1 or 2, wherein said frequency multiplier device is a mixer diode.

4. A short-range Doppler radar according to claims 1 or 2, wherein said oscillator and said frequency multiplier device are unitarily constructed of a single Gunn diode.

5. A short-range Doppler radar according to claim 1, wherein said filter means includes a narrow band filter capable of passing a higher harmonic frequency component equal to nfo, where fo is the frequency of the oscillator output and n is an integer in the range of 2 to 5 inclusive.

6. A short-range Doppler radar according to claim 1, wherein said radiating means is a horn antenna.

7. A short-range Doppler radar according to claims 1 or 2, wherein said oscillator comprises a Gunn diode.

8. A short-range Doppler radar comprising microwave signal generating means for generating a fundamental frequency signal and a range of higher harmonic frequency components thereof;

filter means connected to said signal generating means for passing only a selected harmonic frequency component;

antenna means for radiating said selected harmonic frequency component and for receiving reflected waves thereof; and

means for detecting the Doppler frequency component in the received reflected waves.

13. A short-range Doppler radar according to claim 8, wherein said microwave signal generating means comprises an oscillator generating said fundamental frequency signal and a frequency multiplier device connected to said oscillator for generating said range of higher harmonic frequency components.

14. A short-range Doppler radar according to claim 13, wherein said frequency multiplier device is a mixer diode.

9. A short-range Doppler radar comprising microwave signal generating means for generating a fundamental frequency signal and a range of higher harmonic frequency components thereof;

filter means connected to said signal generating means for passing only a selected harmonic frequency component;

antenna means for radiating said selected harmonic frequency component and for receiving reflected waves thereof;

means for detecting the Doppler frequency component in the received reflected waves, and a dielectric substrate having a metallic layer on one side thereof and having a micro-integrated circuit formed on the other side thereof, which circuit comprises said microwave signal generating means.

10. A short-range Doppler radar according to claim 9, wherein said filter means comprises a window provided in said dielectric substrate and a waveguide coupling said window to said antenna means.

11. A short-range Doppler radar according to claim 9, wherein said filter means includes a narrow band filter capable of passing a higher harmonic frequency component equal to nfo, where fo is the frequency of said fundamental frequency signal and n is an integer in the range of 2 to 5 inclusive.

12. A short-range Doppler radar according to claim 11, wherein said window is dimensioned to pass frequencies in a range of n·

fo and below, and said waveguide is dimensioned to pass frequencies of nfo and above.

15. A short-range Doppler radar according to claim 9, wherein said microwave signal generating means comprises a single Gunn diode.

16. A short-range Doppler radar comprising

an oscillator which generates a fundamental frequency wave;

a mixer diode which is driven by an output of said oscillator and generates a range of higher harmonic frequency components of said fundamental frequency wave and mixes said fundamental frequency wave with received reflected waves;

filter means for passing only a selected harmonic frequency component of the output generated by said mixer diode;

antenna means coupled to said mixer diode for radiating said selected harmonic frequency component and for receiving reflected waves thereof;

and means connected to said mixer diode for selecting the Doppler frequency in the received reflected waves.

17. A short-range Doppler radar according to claim 16, including a dielectric substrate having a metallic layer on one side thereof and a micro-integrated circuit formed on the other side thereof, which circuit at least comprises said mixer diode and said selecting means.

18. A short-range Doppler radar according to claim 17, wherein said filter means comprises a window provided in said dielectric substrate and a waveguide coupling said window to said antenna means.

19. A short-range Doppler radar according to claim 17, wherein said filter means includes a narrow band filter capable of passing a higher harmonic frequency component equal to n·

f_o, wherein f_o is the frequency of said fundamental frequency wave and n is an integer in the range of 2 to 5 inclusive.

20. A short-range Doppler radar according to claim 18, wherein said window is dimensioned to pass frequencies in a range of n·

f_o and below, and said waveguide is dimensioned to pass frequencies in a range of n·

f_o and above.

21. A short-range Doppler radar according to claim 17, wherein said mixer diode is a Gunn diode.

22. A short-range Doppler radar comprising

generating means including a diode for generating a fundamental frequency wave and a range of higher harmonic frequency components of said fundamental frequency wave and for mixing said fundamental wave with received reflected waves;

filter means for passing only a selected harmonic frequency component of the waves generated by said generating means;

antenna means coupled to said diode for radiating said selected harmonic frequency component and for receiving reflected waves thereof; and

means connected to said diode for selecting the Doppler frequency in the received reflected waves.

23. A short-range Doppler radar according to claim 22, including a dielectric substrate having a metallic layer on one side thereof and a micro-integrated circuit formed on the other side thereof, which circuit at least comprises said selecting means.

24. A short-range Doppler radar according to claim 23, wherein said filter means comprises a window provided in said dielectric substrate and a waveguide connected to said window.

25. A short range Doppler radar according to claim 23, wherein said filter means includes a narrow band filter capable of passing a higher harmonic frequency component equal to n·

f_o, where f_o is the frequency of said fundamental frequency wave and n is an integer in the range of 2 to 5 inclusive.

26. A short-range Doppler radar according to claim 23, wherein said diode is a Gunn diode.

27. A short-range Doppler radar comprising microwave signal generating means for generating a fundamental frequency signal and a range of higher harmonic frequency components thereof;

filter means connected to said signal generating means for passing only a selected harmonic frequency component;

antenna means for radiating said selected harmonic frequency component and for receiving reflected waves thereof;

means for detecting the Doppler frequency component in the received reflected waves, and wherein said microwave signal generating means comprises a single Gunn diode.