Directional antenna system including pattern control

• US 4,176,356 A
• Filed: 06/27/1977
• Issued: 11/27/1979
• Est. Priority Date: 06/27/1977
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Foster, L. Curtis, Lindholm, Carl E.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US05/810,234
• Time in Patent Office: 883 Days
• Field of Search: 343/100 CS, 343/854, 343/100 SA, 343/117 A, 325/369, 325/381, 325/304, 325/305
• US Class Current: 342/367
• CPC Class Codes: G01S 3/38 using adjustment of real or effective orientation of directivity characteristic of an antenna or an antenna system to give a desired condition of signal derived from that antenna or antenna system, e.g. to give a maximum or minimum signal G01S3/16, G01S3/28 take precedence
• CPC Class Codes: H01Q 1/3275 mounted on a horizontal surface of the vehicle, e.g. on roof, hood, trunk
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence

Abstract

A directional antenna system is disclosed which selectively couples two radiating antenna elements to a transceiver through a selective phase, magnitude and matching network which is controlled by the output of a logic circuit. The network provides for equal magnitude current coupling between the transceiver and the two antennas while simultaneously selectively producing either positive or negative approximately 90° phase shifts between the two antennas to produce either of two discrete directive cardioid radiation patterns directed in substantially opposite directions. The logic circuit, in conjunction with a manual step switch, provides for a manually selecting either of the two cardioid radiation patterns, as well as producing a figure eight or an omnidirectional radiation pattern. For generating a transceiver omnidirectional pattern, one antenna is used and the other is connected to a standard broadcast band receiver. Matching networks are simultaneously selectively connected between the two antennas and the transceiver such that maximum power transfer and impedance matching is maintained for different radiation patterns. An automatic scanning switch is coupled to the logic circuit and provides for automatically selecting one of the cardioid radiation patterns as an optimum pattern in which the signal from the remote site is most strongly received by the transceiver. Indicating lights are provided to indicate which one of the radiation patterns is generated for the transceiver.

Claims

1. A directive antenna system comprising:

a motor vehicle movable in a straight line direction;

first transceiver communication means carried by said motor vehicle and operative at a first frequency for establishing communications with a site remotely located from said first communication means;

second communication means carried by said vehicle and operative at a second frequency for establishing commumications with other remote sites;

a plurality of at least two antenna elements mounted to said vehicle and selectively coupled to said first and second communication means for providing radiation patterns for said first and second communication means;

said two antenna elements positioned on said motor vehicle at approximately one quarter of a wavelength apart at the operating frequency of said first transceiver communication means, said two antenna elements mounted along a line substantially parallel to the straight line direction of movement of the motor vehicle;

means including a network coupled to said antenna elements for selectively generating and maintaining any one of a plurality of at least two discrete directive radiation patterns for said first transceiver communication means by simultaneously utilizing said two antenna elements while selectively providing various phase differences between said utilized antenna elements and simultaneously providing for substantially equal magnitude current coupling between said utilized antenna elements and said first communication means, said network also selectively utilizing each one of said two antenna elements to simultaneously generate a separate radiation pattern for each of said first and second communication means, respectively,

said plurality of directive radiation patterns for said first communication means including at least two radiation patterns which have substantial nulls directed in substantially different directions;

first means for indicating which one of said plurality of directive radiation patterns is selectively generated for said first communication means; and

second means for indicating the magnitude of a desired signal transmitted at said remote site and received by said first communication means in the selected directive radiation pattern; and

means coupled to said network for automatically selecting one of said directive radiation patterns as an optimum pattern for said first communication means, said automatically selected optimum radiation pattern corresponding to the one pattern of said plurality of directive patterns in which a desired signal is most strongly received by said first communication means.

2. A directive antenna system comprising:

communication means operative at a carrier frequency for establishing communications with a remote site;

means coupled to said communication means for selectively generating a plurality of discrete directive radiation patterns for said communication means; and

means coupled to said radiation pattern generating means for automatically selecting one of said radiation patterns as an optimum pattern for said communication means, said automatically selected optimum radiation pattern corresponding to the one pattern of said plurality of patterns in which a desired signal is most strongly received by said communication means;

whereby the communication means is automatically able to avoid interferring signals which are not directly in line between the communication means and the remote site;

said directive antenna system including indicating means coupled to said radiation pattern generating means for indicating which one of said plurality of directive radiation patterns is selectively generated for said communication means, whereby said indicating means, in conjunction with said pattern selecting means, generally provides information as to the location of the remote site with respect to the location of said communication means.

3. A directive antenna system according to claim 2 wherein said communication means comprises transceiver apparatus.

4. A directive antenna system according to claim 2 wherein said automatic selecting means includes circuitry for monitoring an AGC signal of a receiver portion of said communication means in order to determine the pattern which produces the strongest desired received signal.

5. A directive antenna system according to claim 4 wherein said automatic selecting means includes circuitry for sequentially stepping said radiation pattern generating means through said plurality of radiation patterns while monitoring said AGC signal in order to determine the optimum radiation pattern for receiving said desired signal.

6. A directive antenna system according to claim 5 which includes means, in addition to said automatic selecting means, for manually selecting any one of said plurality of radiation patterns.

7. A directive antenna system according to claim 5 wherein said radiation pattern generating means includes a plurality of antenna elements mounted on a motor vehicle.

8. A directive antenna system according to claim 7 wherein said plurality of antenna elements comprise a first and a second antenna element spaced approximately one quarter of a wavelength apart at the operative carrier frequency of said communication means.

9. A directive antenna system according to claim 8 wehrein said radiation pattern generating means includes circuitry for providing a positive and negative predetermined phase difference between said first and second antenna elements to create two oppositely directed generally cardioid shaped radiation patterns for said communication means.

10. A directive antenna system according to claim 2 wherein said indicating means comprises a series of lights with at least one individual light corresponding to each of said plurality of radiation patterns.

11. A directive antenna system according to claim 2 wherein said communication means comprises a radio transceiver having a housing, and said indicating means are located in a container attached to said housing.

12. A directive antenna system according to claim 11 wherein said automatic selecting means is also substantially located in said container.

13. A directive antenna system according to claim 12 wherein an electrical connection exists between said transceiver means and said automatic selecting means through which a AGC signal of the transceiver means is monitored by said automatic selecting means.

14. A directive antenna system comprising:

communication means operative at a frequency for establishing communications with a site remotely located from said communication means;

a plurality of antenna elements coupled to said communication means for providing radiation patterns for said communication means; and

means coupled to said antenna elements for selectively generating a plurality of discrete directive radiation patterns for said communication means by simultaneously utilizing at least two of said antenna elements at any one time,

said selective radiation pattern generating means including a network coupling said plurality of antenna elements to said communication means and selectively providing various phase differences between said utilized antenna elements while simultaneously providing for substantially equal magnitude current coupling between said utilized antenna elements and said communication means, whereby substantially identical but differently directed radiation patterns can be created by the use of various phase differences in conjunction with controlling of the magnitude coupling of the radiation currents between the antenna elements and the communication means.

15. A directive antenna system according to claim 14 wherein said plurality of radiation patterns includes at least two radiation patterns directed in substantially opposite directions.

16. A directive antenna system according to claim 15 wherein said network provides positive and negative predetermined phase differences between two of said utilized antenna elements to create said two oppositely directed radiation patterns for said communication device.

17. A directive antenna system according to claim 16 wherein said utilized antenna elements consist of two elements approximately one quarter of a wavelength apart at the operating frequency of said communication means, and wherein said oppositely directed radiation patterns are generally cardioid shaped, and wherein said network provides a positive and negative difference of approximately 90°

between said two utilized antenna elements to produce said oppositely directed cardioid radiation patterns.

18. A directive antenna system according to claim 16 wherein for generating one of said oppositely directed radiation pattern said network provides a variable capacitor coupled between said communication means and one of said utilized antenna elements and a variable capacitor in series with an inductor between said communication means and the other of said utilized antenna elements, and wherein said network provides substantially the opposite type of connection between said utilized antenna elements and said communication means for generating the other of said oppositely directed radiation pattern.

19. A directive antenna system according to claim 18 wherein said network provides a first impedance matching network for matching said utilized antenna elements to said communication means while generating said one of said one of said oppositely directed radiation patterns, and wherein said network provides a second impedance matching network between said two utilized elements and said communication means while generating the other of said oppositely directed radiation patterns.

20. A directive antenna system according to claim 18 wherein said utilized antenna elements consist of two elements approximately one quarter of a wavelength apart at the operating frequency of said communication means, and wherein said oppositely directed radiation patterns are generally cardioid shaped.

21. A directive antenna system according to claim 20 wherein said network provides a positive and negative difference of approximately 90°

between said two utilized antenna elements to produce said oppositely directed cardioid radiation patterns.

22. A directive antenna system according to claim 21 wherein said approximately 90°

phase difference is substantially 70°

.

23. A directive antenna system according to claim 20 wherein said radiation pattern generating means also includes structure for utilizing said two antenna elements to produce a figure eight radiation pattern.

24. A directive antenna system according to claim 20 wherein said two antenna elements are mounted on a motor vehicle and are mounted in a line parallel to the direction of motion of said motor vehicle.

25. A directive antenna system comprising:

transceiver means operable at a carrier frequency and adaptable to be carried by a motor vehicle for establishing two-way communications between the motor vehicle and a remote site;

at least two antenna elements adapted to be carried by said motor vehicle for establishing radiation patterns for said transceiver means;

means coupled to said antenna elements for selectively generating and maintaining any one of a plurality of discrete directive radiation patterns for said transceiver means by simultaneously utilizing said two antenna elements, said plurality of radiation patterns including at least two radiation patterns which have substantial nulls directed in substantially opposite directions;

said two utilized antenna elements adapted to be positioned on said motor vehicle at approximately one quarter of a wavelength apart at the operating frequency of said transceiver means, said two antenna elements adapted to be mounted along a line substantially parallel to the straight line of movement of the motor vehicle.

26. A directive antenna system according to claim 25 wherein said radiation pattern generating means produces a first cardioid radiation pattern directed in the forward direction of motion of said motor vehicle with a substantial null in the rearward direction and a second cardioid radiation pattern directed in the rearward direction of motion of said motor vehicle with a substantial null in the forward direction.

27. A directive antenna system according to claim 26 wherein said radiation pattern generating means also produces a figure eight radiation pattern having one lobe directed in the forward direction of motion of said motor vehicle and the other lobe directed in the rearward direction of motion of said motor vehicle.

28. A directive antenna system according to claim 26 which includes indicating means coupled to said transceiver means for indicating which of said cardioid radiation patterns is selectively generated for said transceiver means, whereby said indicating means provides information as to the location of the remote site with respect to the location of said transceiver means.

29. A directive antenna system according to claim 28 which includes means coupled to said radiation pattern generating means for automatically selecting one of said cardioid radiation patterns as an optimum radiation pattern, said automatically selected optimum radiation pattern corresponding to the cardioid pattern in which a desired signal is most strongly received by said transceiver means.

30. A directive antenna system according to claim 29 wherein said selective radiation pattern generating means includes a network coupling said antenna elements to said communication means and selectively providing various phase differences between said utilized antenna elements while simultaneously providing for substantially equal magnitude current coupling between said utlized antenna elements and said communication means, whereby substantially identical but differently directed radiation patterns can be created by the use of various phase differences in conjunction with controlling of the coupling of the radiation currents between the antenna elements and the communication means.

31. A directive antenna system according to claim 25 wherein said selective radiation pattern generating means includes a network coupling said antenna elements to said communication means and selectively providing various phase differences between said utilized antenna elements while simultaneously providing for substantially equal magnitude current coupling between said utilized antenna elements and said communication means, whereby substantially identical but differently directed radiation patterns can be created by the use of various phase differences in conjunction with controlling the coupling of the radiation currents between the antenna elements and the communication means.

32. A directive antenna system comprising:

a motor vehicle movable in a straight line direction;

transceiver means operable at a carrier frequency and carried by said motor vehicle for establishing two-way communications between the motor vehicle and a remote site;

at least two antenna elements mounted to said motor vehicle for establishing radiation patterns for said transceiver means;

means coupled to said antenna elements for selectively generating and maintaining any one of a plurality of discrete directive radiation patterns for said transceiver means by simultaneously utilizing said two antenna elements, said plurality of radiation patterns including at least two radiation patterns which have substantial nulls directed in substantially different directions;

said two utilized antenna elements positioned on said motor vehicle at approximately one quarter of a wavelength apart at the operating frequency of said transceiver means, said two antenna elements mounted along a line substantially parallel to the straight line direction of movement of the motor vehicle.

33. A directive antenna system according to claim 32 wherein said radiation pattern generating means produces a first cardioid radiation pattern directed in the forward direction of motion of said motor vehicle with a substantial null in the rearward direction and a second cardioid radiation pattern directed in the rearward direction of motion of said motor vehicle with a substantial null in the forward direction.

34. A directive antenna system according to claim 33 which includes indicating means coupled to said transceiver means for indicating which of said cardioid radiation patterns is selectively generated for said transceiver means, whereby said indicating means provides information as to the location of the remote site with respect to the location of said vehicle and transceiver means.

35. A directive antenna system according to claim 34 which includes means coupled to said radiation pattern generating means for automatically selecting one of said cardioid radiation patterns as an optimum radiation pattern, said automatically selected optimum radiation pattern corresponding to the cardioid pattern in which a desired signal is most strongly received by said transceiver means.

36. A directive antenna system according to claim 32 wherein said selective radiation pattern generating means includes a network coupling said antenna elements to said communication means and selectively providing various phase differences between said utilized antenna elements while simultaneously providing for substantially equal magnitude current coupling between said utilized antenna elements and said communication means, whereby substantially identical but differently directed radiation patterns can be created by the use of various phase differences in conjunction with controlling of the coupling of the radiation currents between the antenna elements and the communication means.

37. A directive antenna system comprising:

first communication means operative at a first frequency for establishing communications with a site remotely located from said communication means;

second communication means operative at a second frequency for establishing communications with other remote sites;

a plurality of antenna elements selectively coupled to said first and second communication means for providing radiation patterns for said first and second communication means; and

means coupled to said antenna elements for selectively generating at least one discrete directive radiation pattern for said first communication means by simultaneously utilizing at least two of said antenna elements at one time, and also for selectively separately utilizing each one of said two antenna elements to simultaneously generate a separate radiation pattern for each of said first and second communication means respectively.

38. A directive antenna system according to claim 37 wherein said plurality of antenna elements consists of a first and a second antenna element.

39. A directive antenna system according to claim 38 wherein said separate radiation patterns are created by said selective pattern generating means independently coupling said first communication means to said first antenna element and said second communication means to said second element.

40. A directive antenna system according to claim 39 wherein said separate radiation patterns are substantially omnidirectional.

41. A directive antenna system according to claim 39 wherein said selective pattern generating means creates said one directive radiation pattern by coupling said first communication means to both said first and second antenna elements.

42. A directive antenna system according to claim 41 wherein said second communication means is isolated from said antenna elements during the creation of said one directive radiation pattern for said first communication means.

43. A directive antenna system according to claim 42 wherein said first communication means is a CB transceiver and said second communication means includes a receiver.

44. A directive antenna system according to claim 37 wherein said plurality antenna elements comprise two antenna elements that are mounted to a motor vehicle which is movable in a straight line, said two antenna elements mounted along a line substantially parallel to the straight line direction of movement of the motor vehicle.

45. A directive antenna system according to claim 37 wherein said coupling means generates at least two directive radiation patterns for said first communication means.

46. A directive antenna system according to claim 45 wherein said coupling means includes means for automatically selecting one of said directive radiation patterns as an optimum pattern for said first communication means, said automatically selected optimum radiation pattern corresponding to the one pattern of said plurality of patterns in which a desired signal is most strongly received by said first communication means.

47. A directive antenna system according to claim 45 wherein said coupling means includes a network coupling said plurality of antenna elements to said first communication means and selectively producing said directive radiation patterns by providing various phase differences between two of said antenna elements while simultaneously providing for substantially equal magnitude current coupling between said two antenna elements and said first communication means, whereby substantially identical but differently directed radiation patterns can be created by the use of various phase differences in conjunction with controlling of the magnitude coupling of the radiation currents between the antenna elements and the first communication means.

48. A directive antenna system comprising:

communication means operative at a carrier frequency for establishing communications with a remote site;

means coupled to said communication means for selectively generating and maintaining any one of a plurality of discrete directive radiation patterns for said communication means;

first means for indicating which one of said plurality of directive radiation patterns is selectively generated for said communication means; and

second means for visually indicating the magnitude of a desired signal transmitted at said remote site and received by said communication means for the selected directive radiation pattern;

whereby said first and second means provide information as to the location of the remote site with respect to said communication means.

49. A directive antenna system according to claim 48 wherein said selective radiation pattern generating means includes a manual actuator for selecting any of said plurality of radiation patterns.