Content-based adaptive parasitic array antenna system

• US 6,492,942 B1
• Filed: 11/07/2000
• Issued: 12/10/2002
• Est. Priority Date: 11/09/1999
• Status: Expired due to Fees

• Current Assignee: Com DEV International Limited (Honeywell International Inc.)
• Original Assignee: Com DEV International Limited (Honeywell International Inc.)
• Inventors: Kezys, Vytas
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US09/707,855
• Time in Patent Office: 763 Days
• Field of Search: 342/368, 342/383, 342/372, 342/377
• US Class Current: 342/368
• CPC Class Codes: H01Q 19/32 the primary active element being end-fed and elongated
• CPC Class Codes: H01Q 21/0025 Modular arrays
• CPC Class Codes: H01Q 21/20 the units being spaced along or adjacent to a curvilinear path slotted waveguide arrays H01Q21/005; circularly or helically slotted waveguides H01Q21/0062
• 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
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H01Q 3/44 varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element
• CPC Class Codes: H01Q 3/446 the radiating element being at the centre of one or more rings of auxiliary elements
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming

Abstract

An adaptive parasitic array antenna system having properties of directive gain, self-pointing and interference rejection is provided including an adaptive parasitic array antenna comprising at least one active element and one or more parasitic elements coupled to controlled impedances (CI). The system further comprises a transceiver, a content-based optimization criterion computation module (CBOCCM), and a control variable optimizer (CVO). The CBOCCM receives a signal waveform from the active element through the transceiver, and computes an optimization criterion (OC) based on the content of the received signal. The optimization criterion is coupled to the CVO, which adaptively computes one or more control variables (CV), which are coupled to the controlled impedances CI in order to adjust the beampattern created by the adaptive parasitic array antenna. Also disclosed are two preferred adaptation implementations and algorithms, a pilot-tone based adaptation system, and a decision-directed based adaptation system.

Claims

1. An antenna system, comprising:

an array antenna for generating a beam pattern, the array antenna comprising at least one active element and a plurality of parasitic elements, wherein the active element is coupled to a transceiver for transmitting and receiving data signals, and the parasitic elements are coupled to controlled impedance networks; and

an adaptation controller coupled to the transceiver and the array antenna for extracting content information from the received data signals and altering the impedance of the controlled impedance networks in order to adapt the beam pattern of the array antenna, wherein the content information includes a pilot tone signal contained within the received data signals.

2. The antenna system of claim 1, wherein the adaptation controller comprises:

an optimization criterion computation module for computing an optimization criterion based upon the content information of the received data signals; and

a control variable optimizer for computing a plurality of control variables based upon the optimization criterion, wherein the control variables are coupled to the controlled impedance networks.

3. The antenna system of claim 2, wherein the adaptation controller further comprises:

a protocol controller for managing the operation of the optimization criterion computation module and the control variable optimizer.

4. The antenna system of claim 3, wherein the control variables alter the impedance of the controlled impedance networks.

6. The antenna system of claim 1, wherein the content information further includes a plurality of data symbols contained within the received data signals.

7. The antenna system of claim 2, wherein the adaptation controller further comprises a memory for storing a plurality of sets of control variables.

8. The antenna system of claim 2, wherein the adaptation controller further comprises a non-linear mapper coupled between the control variables and the controlled impedance networks.

9. The antenna system of claim 1, wherein the array antenna further comprises a matching network coupled to the active element.

10. The antenna system of claim 2, wherein the optimization criterion is signal to noise ratio (SNR).

11. The antenna system of claim 2, wherein the optimization criterion is signal to interference plus noise ratio (SINR).

12. The antenna system of claim 2, wherein the optimization criterion is bit error rate (BER).

13. The antenna system of claim 2, wherein the control variable optimizer computes a control variable for each of the parasitic elements of the array antenna.

14. The antenna system of claim 13, wherein the control variables are normalized.

15. The antenna system of claim 2, wherein the control variables represent a voltage level that is coupled to the controlled impedance networks in order to alter the impedance of the networks.

16. The antenna system of claim 3, wherein the protocol controller is further coupled to the transceiver for transmitting control information to another antenna system.

17. The antenna system of claim 1, wherein the beam pattern of the array antenna is continuously adapted based upon the content information in the received data signal.

18. The antenna system of claim 17, wherein the adaptation controller computes an optimization criterion based upon the content information of the received data signal and continuously generates a plurality of control variables for altering the impedance of the controlled impedance networks.

19. The antenna system of claim 1, wherein the controlled impedance networks each include a PIN diode.

20. The antenna system of claim 1, wherein the controlled impedance networks each include a negative resistance device.

21. The antenna system of claim 20, wherein the negative resistance device is a tunnel diode.

22. The antenna system of claim 1, wherein the controlled impedance networks each include a PIN diode and a tunnel diode.

23. The antenna system of claim 1, wherein the plurality of parasitic elements include between 6 and 32 parasitic elements.

24. The antenna system of claim 1, wherein the active element and the plurality of parasitic elements are mounted on a planar structure in which the active element is mounted in the center of the planar structure and the plurality of parasitic elements are mounted in a geographic pattern around the active element.

26. The antenna system of claim 19, wherein the content information further includes a plurality of data symbols contained within the received data signal.

27. The antenna system of claim 26, wherein the transceiver includes a digital modem for extracting a plurality of data symbols from the received data signals.

51. The method of claim 24, wherein step (D) further comprises the steps of:

(D)(i) computing an optimization criterion based upon the content information of the received data signals;

(D)(ii) computing a plurality of control variables based upon the optimization criterion; and

(D)(iii) applying the control variables to the controlled impedance networks.

52. The method of claim 51, wherein the control variables alter the impedance of the controlled impedance networks.

53. The method of claim 51, further comprising the step of storing a plurality of sets of control variables in a memory.

54. The method of claim 53, further comprising the steps of:

determining whether the beam pattern of the array antenna can be adapted to a predetermined threshold level; and

if not, then obtaining a set of control variables from the memory and applying these control variables to the controlled impedance networks.

55. The method of claim 51, wherein step (D) further comprises the step of:

(D)(iv) applying a non-linear mapping to the control variables.

5. An antenna system, comprising:

an array antenna for generating a beam pattern, the array antenna comprising at least one active element and a plurality of parasitic elements, wherein the active element is coupled to a transceiver for transmitting and receiving data signals, and the parasitic elements are coupled to controlled impedance networks, wherein the beam pattern of the array antenna is continuously adapted based upon the content information in the received data signal, and wherein the transceiver includes a digital modem for extracting a plurality of data symbols from the received data signals; and

an adaptation controller coupled to the transceiver and the array antenna for extracting content information from the received data signals and altering the impedance of the controlled impedance networks in order to adapt the beam pattern of the array antenna, wherein the adaptation controller computes an optimization criterion based upon the content information of the received data signal and continuously generates a plurality of control variables for altering the impedance of the controlled impedance networks, wherein the adaptation controller further comprises;

a normalization circuit coupled to the received data signals for computing a normalized received data signal;

a reconstruction circuit coupled to the plurality of data symbols for computing a reconstructed received data signal from the plurality of data symbols;

an optimization criterion computation module for computing the optimization criterion by comparing the normalized received data signal and the reconstructed received data signal; and

a control variable optimizer for generating the plurality of control variables based upon the optimization criterion.

47. The antenna system of claim 5, wherein the adaptation controller further comprises:

a non-linear mapper coupled between the plurality of control variables and the controlled impedance networks.

48. The antenna system of claim 5, wherein the adaptation controller operates in two modes, an acquisition mode and a tracking mode.

49. The antenna system of claim 5, wherein the adaptation controller further comprises:

a memory for storing a plurality of sets of control variables.

25. An antenna system, comprising:

an array antenna for generating a beam pattern, the array antenna comprising at least one active element and a plurality of parasitic elements, wherein the active element is coupled to a transceiver for transmitting and receiving data signals, and the parasitic elements are coupled to controlled impedance networks, wherein the beam pattern of the array antenna is continuously adapted based upon the content information in the received data signal; and

an adaptation controller coupled to the transceiver and the array antenna for extracting content information from the received data signals and altering the impedance of the controlled impedance networks in order to adapt the beam pattern of the array antenna, wherein the adaptation controller computes an optimization criterion based upon the content information of the received data signal and continuously generates a plurality of control variables for altering the impedance of the controlled impedance networks, and wherein the content information includes a pilot tone signal contained within the received data signals.

28. The antenna system of claim 25, wherein the adaptation controller further comprises a memory for storing a plurality of sets of control variables.

29. The antenna system of claim 25, wherein the adaptation controller further comprises a non-linear mapper coupled between the control variables and the controlled impedance networks.

30. The antenna system of claim 25, wherein the array antenna further comprises a matching network coupled to the active element.

31. The antenna system of claim 25, wherein the optimization criterion is signal to noise ratio (SNR).

32. The antenna system of claim 25, wherein the optimization criterion is signal plus interference to noise ratio (SINR).

33. The antenna system of claim 25, wherein the optimization criterion is bit error rate (BER).

34. The antenna system of claim 25, wherein the control variables are normalized.

35. The antenna system of claim 25, wherein the control variables represent a voltage level that is coupled to the controlled impedance networks in order to alter the impedance of the networks.

36. The antenna system of claim 25, wherein the adaptation controller comprises:

a pilot tone detector for extracting the pilot tone signal from the received data signals;

an optimization criterion computation module for computing the optimization criterion based upon the pilot tone signal; and

a control variable optimizer for generating the plurality of control variables based upon the optimization criterion.

37. The antenna system of claim 36, wherein the adaptation controller further comprises:

a memory for storing a plurality of sets of control variables.

38. The antenna system of claim 36, wherein the adaptation controller further comprises:

a non-linear mapper coupled between the plurality of control variables and the controlled impedance networks.

39. The antenna system of claim 36, wherein the adaptation controller further comprises:

a pilot tone signal generator for generating a pilot tone signal; and

a protocol controller coupled to the transceiver and the pilot tone signal generator for controlling when the pilot tone signal is transmitted from the array antenna.

40. The antenna system of claim 39, wherein the transceiver further comprises:

an RF/baseband converter;

a mixer; and

a modem.

41. The antenna system of claim 39, wherein the protocol controller inhibits the control variable optimizer when the system is transmitting.

42. The antenna system of claim 40, wherein the mixer is coupled to a transmit data signal and the pilot tone signal and generates a mixed signal.

43. The antenna system of claim 40, wherein the adaptation controller operates in two modes, an acquisition mode and a tracking mode, and wherein the protocol controller mutes the modem of the transceiver when the adaptation controller is in acquisition mode.

44. The antenna system of claim 42, wherein the pilot tone signal is continuously added to the transmit data signal.

45. The antenna system of claim 42, wherein the transmitter alternates between transmitting the transmit data signal and the pilot tone signal.

46. The antenna system of claim 25, wherein the pilot tone signal is a pseudo-random noise sequence.

50. A method of operating an array antenna having at least one active element and a plurality of parasitic elements, the method comprising the steps of:

(A) providing a plurality of controlled impedance networks coupled to each of the parasitic elements;

(B) receiving a data signal at the array antenna;

(C) extracting content information from the received data signal, wherein step (C) further comprises the step of extracting a pilot tone signal from the received data signal; and

(D) altering the impedance of the controlled impedance networks based upon the content information so as to adapt the beam pattern of the array antenna.

56. A method of operating an array antenna having at least one active element and a plurality of parasitic elements, the method comprising the steps of:

(A) providing a plurality of controlled impedance networks coupled to each of the parasitic elements;

(B) receiving a data signal at the array antenna;

(C) extracting content information from the received data signal, wherein step (C) further comprises the steps of;

(C)(i) normalizing the received data signal;

(C)(ii) generating a reconstructed data signal from the received data signal; and

(C)(iii) comparing the normalized received data signal to the reconstructed data signal; and

(D) altering the impedance of the controlled impedance networks based upon the content information so as to adapt the beam pattern of the array antenna.

57. A system, comprising:

an array antenna having an active element and a plurality of parasitic elements, wherein each of the parasitic elements is coupled to a controlled impedance network; and

a controller that receives a data signal from the array antenna and alters the impedance of the controlled impedance networks based upon the content of the data signal, wherein the data signal includes a pilot tone.

58. The system of claim 57, wherein the array antenna generates a beam pattern, and wherein the controller alters the impedance of the controlled impedance networks in order to adapt the beam pattern of the array antenna.

59. The system of claim 58, wherein the beam pattern of the array antenna is continuously adapted based upon the content of the received data signal.

60. The system of claim 59, wherein the controller computes an optimization criterion based upon the content of the received data signal and continuously generates a plurality of control variables for altering the impedance of the controlled impedance networks.

61. The system of claim 59, wherein the controller further comprises a memory for storing the control variables.

62. The system of claim 59, wherein the controller further comprises a non-linear mapper circuit.

63. The system of claim 59, wherein the array antenna further comprises a matching network coupled to the active element.

64. The system of claim 59, wherein the optimization criterion is signal to noise ratio (SNR).

65. The system of claim 59, wherein the optimization criterion is signal to interference plus noise ratio (SINR).

66. The system of claim 59, wherein the optimization criterion is bit error rate (BER).

67. The system of claim 59, wherein the control variables are normalized.

68. The system of claim 59, wherein the control variables provide a voltage level that alters the impedance of the controlled impedance networks.

69. The system of claim 57, further comprising:

a receiver coupled to the active element in order to receive a data signal.

70. The system of claim 57, further comprising:

a transceiver coupled to the active element in order to receive a data signal and also to transmit a data signal.

71. The system of claim 70, further comprising a protocol controller coupled to the transceiver for transmitting control information to another system.

72. The system of claim 57, wherein the controller comprises:

an optimization circuit for generating an optimization criterion based upon the content of the received data signal; and

a control variable circuit for generating a plurality of control variables based upon the optimization criterion, wherein the control variables are coupled to the controlled impedance networks.

73. The system of claim 72, wherein the controller further comprises:

a protocol circuit for managing the operation of the optimization circuit and the control variable circuit.

74. The system of claim 73, wherein the control variables alter the impedance of the controlled impedance networks.

75. The system of claim 72, wherein the controller further comprises a memory for storing the control variables.

76. The system of claim 72, wherein the controller further comprises a non-linear mapper circuit.

77. The system of claim 72, wherein the optimization criterion is signal to noise ratio (SNR).

78. The system of claim 72, wherein the optimization criterion is signal to interference plus noise ratio (SINR).

79. The system of claim 72, wherein the optimization criterion is bit error rate (BER).

80. The system of claim 72, wherein the control variable circuit computes a control variable for each of the parasitic elements of the array antenna.

81. The system of claim 80, wherein the control variables are normalized.

82. The system of claim 72, wherein the control variables provide a voltage level to alter the impedance of the controlled impedance networks.

83. The system of claim 57, wherein the content of the data signal includes a plurality of digital data symbols.

84. The system of claim 57, wherein the array antenna further comprises a matching network coupled to the active element.

85. The system of claim 84, wherein the matching network is adjustable.

86. The system of claim 57, wherein the controlled impedance networks each include a PIN diode.

87. The system of claim 57, wherein the controlled impedance networks each include a negative resistance device.

88. The system of claim 87, wherein the negative resistance device is a tunnel diode.

89. The system of claim 57, wherein the controlled impedance networks each include a PIN diode and a tunnel diode.

90. The system of claim 57, wherein the plurality of parasitic elements include between 6 and 32 parasitic elements.

91. The system of claim 57, wherein the active element and the plurality of parasitic elements are mounted on a planar structure in which the active element is mounted in the center of the planar structure and the plurality of parasitic elements are mounted in a geographic pattern around the active element.

92. A system, comprising:

an array antenna having an active element and a plurality of parasitic elements, wherein each of the parasitic elements is coupled to a controlled impedance network; and

a controller that receives a data signal from the array antenna and alters the impedance of the controlled impedance networks based upon the content of the data signal;

wherein the array antenna generates a beam pattern, and wherein the controller alters the impedance of the controlled impedance networks in order to adapt the beam pattern of the array antenna, wherein the beam pattern of the array antenna is continuously adapted based upon the content of the received data signal, and wherein the content includes a pilot tone signal contained within the received data signals.

93. The system of claim 92, wherein the content includes a plurality of data symbols contained within the received data signals.

94. The system of claim 93, further comprising a transceiver having a digital modem for extracting a plurality of data symbols from the received data signal.

95. The system of claim 94, wherein the controller further comprises:

a normalization circuit coupled to the received data signals for computing a normalized received data signal;

a reconstruction circuit coupled to the plurality of data symbols for computing a reconstructed received data signal from the plurality of data symbols;

an optimization criterion computation module for computing the optimization criterion by comparing the normalized received data signal and the reconstructed received data signal; and

a control variable optimizer for generating the plurality of control variables based upon the optimization criterion.

96. The system of claim 95, wherein the controller further comprises:

a memory for storing a plurality of sets of control variables.

97. The system of claim 95, wherein the controller further comprises:

a non-linear mapper coupled between the plurality of control variables and the controlled impedance networks.

98. The system of claim 95, wherein the controller operates in two modes, an acquisition mode and a tracking mode.

99. The system of claim 92, wherein the controller comprises:

a pilot tone detector for extracting the pilot tone signal from the received data signals;

an optimization criterion circuit for computing the optimization criterion based upon the pilot tone signal; and

a control variable optimizer for generating the plurality of control variables based upon the optimization criterion.

100. The system of claim 99, wherein the controller further comprises:

a memory for storing a plurality of sets of control variables.

101. The system of claim 99, wherein the controller further comprises:

a non-linear mapper circuit for generating a plurality of non-linear control variables.

102. The system of claim 99, wherein the controller further comprises:

a pilot tone signal generator for generating a pilot tone signal; and

a protocol controller coupled to a transceiver and the pilot tone signal generator for controlling when a pilot tone signal is transmitted from the array antenna.

103. The system of claim 102, wherein the transceiver further comprises:

an RF/baseband converter;

a mixer; and

a modem.

104. The system of claim 103, wherein the mixer is coupled to a transmit data signal and the pilot tone signal and generates a mixed signal.

105. The system of claim 103, wherein the controller operates in two modes, an acquisition mode and a tracking mode, and wherein the protocol controller mutes the modem of the transceiver when the controller is in acquisition mode.

106. The system of claim 103, wherein the protocol controller inhibits the control variable optimizer when the system is transmitting.

107. The system of claim 104, wherein the pilot tone signal is continuously added to the transmit data signal.

108. The system of claim 104, wherein the transmitter alternates between transmitting the transmit data signal and the pilot tone signal.

109. The system of claim 92, wherein the pilot tone signal is a pseudo-random noise sequence.

110. A pilot-tone based adaptive array antenna system, comprising:

an array antenna having at least one active element and a plurality of parasitic elements, wherein each of the plurality of parasitic elements is terminated with a controlled impedance network;

a transceiver coupled to the active element for received a data signal from the array antenna and for transmitting a data signal to the array antenna; and

an adaptation controller coupled between the transceiver and the plurality of parasitic elements, wherein the adaptation controller comprises;

an optimization criterion computation module for extracting a pilot tone signal from the received data signal and for generating an optimization criterion; and

a control variable optimizer for generating a set of control variables based upon the optimization criterion, wherein the control variables are applied to the controlled impedance networks in order to adapt the beam pattern of the array antenna.

111. A decision-directed based adaptive array antenna system, comprising:

an array antenna having at least one active element and a plurality of parasitic elements, wherein each of the plurality of parasitic elements is terminated with a controlled impedance network;

a transceiver coupled to the active element for received a data signal from the array antenna and for transmitting a data signal to the array antenna; and

an adaptation controller coupled between the transceiver and the plurality of parasitic elements, wherein the adaptation controller comprises;

an optimization criterion computation module for generating an optimization criterion by comparing the received data signal with a reconstructed version of the received data signal; and

a control variable optimizer for generating a set of control variables based upon the optimization criterion, wherein the control variables are applied to the controlled impedance networks in order to adapt the beam pattern of the array antenna.