Antenna tuning unit

• US 9,584,191 B2
• Filed: 12/20/2013
• Issued: 02/28/2017
• Est. Priority Date: 12/20/2013
• Status: Active Grant

• Current Assignee: Southern Avionics Co.
• Original Assignee: Southern Avionics Co.
• Inventors: Cowles, Russell Wayne, Hamilton, George Timothy, Sands, Donald James
• Primary Examiner(s): Jain, Ankur
• Assistant Examiner(s): Chen, Zhitong
• Application Number:
  US14/135,919
• Publication Number:
  US 20150180593A1
• Time in Patent Office: 1,166 Days
• US Class Current: 1/1
• CPC Class Codes: H01Q 1/48 Earthing means; Earth screens; Counterpoises
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03H 7/38 Impedance-matching networks
• CPC Class Codes: H03H 7/40 Automatic matching of load impedance to source impedance
• CPC Class Codes: H04B 1/0458 Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages matching circuits in general H03H
• CPC Class Codes: H04B 1/3838 Arrangements for reducing RF exposure to the user, e.g. by changing the shape of the transceiver while in use
• CPC Class Codes: H04B 17/11 for calibration
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 5/73 for taking measurements, e.g. using sensing coils

Abstract

A system, apparatus, and method directed to impedance matching an antenna with a transmitter for non-directional radio beacons. The apparatus includes an L-type impedance network comprising non-capacitive elements and at least one variable inductor on each branch of the impedance network. Also, system, apparatus, and method directed to providing a low power signal for tuning the antenna. The apparatus includes an impedance matching network and a signal generator. Also, a system, apparatus, and method directed to providing an estimate of near-field strength of a signal from an antenna. The apparatus includes an impedance matching network, a near-field signal strength detector, and microcontroller configured to estimate the near-field signal strength. Corresponding systems includes using the respective apparatuses between an antenna and a transmitter. Corresponding methods are directed to the use of the apparatuses and systems.

Claims

1. An apparatus for tuning an electrically short, navigational beacon antenna adapted for use with a radio transmitter and an electrical ground, the apparatus comprising:

an impedance matching network comprising;

a first end configured to be in electrical communication with the radio transmitter, the radio transmitter generating a medium or high power signal between 190 kHz and 1800 kHz with a wavelength about ten times or greater than a longest dimension of the electrically short, navigational beacon antenna;

a second end configured to be in electrical communication with the electrically short, navigational beacon antenna;

a first impedance element electrically connected between the first end and the second end; and

a second impedance element electrically connected between the first end and the electrical ground;

wherein each of the impedance elements comprises an air core variable inductor and wherein each of the impedance elements only comprise non-capacitive circuit components.

2. The apparatus of claim 1, further comprising:

a sensor configured to estimate radio signal strength; and

a microcontroller configured to receive the estimated radio signal strength from the sensor and to transmit the estimated radio signal strength to the radio transmitter.

3. The apparatus of claim 2, wherein the sensor is a near-field signal strength detector.

4. The apparatus of claim 1, further comprising:

a signal generator configured to transmit a generated signal through the impedance matching network separate from the radio transmitter.

5. The apparatus of claim 4, wherein the signal generator is configured to limit the generated signal to a power level below a threshold that is harmful to humans.

6. The apparatus of claim 1, wherein the radio transmitter is configured to operate in frequency band of about 190 kilohertz to about 535 kilohertz.

7. A system for radio tuning, the system adapted for use with an electrical ground comprising:

an electrically short, navigational beacon antenna;

a radio transmitter, the radio transmitter generating a medium or high power signal between 190 kHz and 1800 kHz with a wavelength about ten times or greater than a longest dimension of the electrically short, navigational beacon antenna; and

an antenna tuning unit electrically connected between the electrically short, navigational beacon antenna and the radio transmitter, the antenna tuning unit comprising;

an impedance matching network comprising;

a first end configured to be in electrical communication with the radio transmitter;

a second end configured to be in electrical communication with the electrically short, navigational beacon antenna;

a first impedance element electrically connected between the first end and the second end; and

a second impedance element electrically connected between the first end and the electrical ground;

wherein each of the impedance elements comprises an air core variable inductor and wherein each of the impedance elements only comprise non-capacitive circuit components.

8. The system of claim 7, further comprising:

a sensor configured to estimate radio signal strength; and

a microcontroller configured to receive the estimated radio signal strength from the sensor and to transmit the estimated radio signal strength to the radio transmitter.

9. The system of claim 8, further comprising:

a target radio signal strength; and

a closed loop controller configured to transmit a power adjustment signal to the radio transmitter based on the estimated radio signal strength received from the microcontroller and the target radio signal strength.

10. The system of claim 8, wherein the sensor is a near-field signal strength detector.

11. The system of claim 7, wherein the antenna tuning unit further comprises:

a signal generator configured to transmit a generated signal to the first end.

12. The system of claim 11, wherein the signal generator is configured to limit the generated signal to a power level below a threshold that is harmful to humans.

13. The system of claim 7, wherein the radio transmitter is configured to operate in a frequency band of about 190 kilohertz to about 535 kilohertz.

14. A method for tuning an electrically short, navigational beacon antenna adapted for use with an electrical ground and using an impedance matching network electrically connected between the electrically short, navigational beacon antenna and a radio transmitter, comprising the steps of:

providing the impedance matching network comprising;

a first end configured to receive a signal from the radio transmitter, the radio transmitter generating a medium or high power signal between 190 kHz and 1800 kHz with a wavelength about ten times or greater than a longest dimension of the electrically short, navigational beacon antenna;

a second end electrically connected to the electrically short, navigational beacon antenna;

a first impedance element comprising at least one air core variable inductor and electrically disposed between the first end and the second end; and

a second impedance element comprising at least one air core variable inductor and electrically disposed between the first end and the electrical ground;

wherein each of the impedance elements only comprise non-capacitive circuit components;

the method comprising;

varying a value of at least one of the impedance elements to reduce signal reflection in the signal transmitted from the radio transmitter to the electrically short, navigational beacon antenna.

15. The method of claim 14, wherein the impedance matching network is configured to operate between 190 kilohertz and 535 kilohertz.

16. An apparatus for tuning a navigational beacon antenna adapted for use with a radio transmitter and an electrical ground, the apparatus comprising:

an impedance matching L-network comprising;

a first end configured to be in electrical communication with the radio transmitter, the radio transmitter generating a medium or high power signal between 190 kHz and 1800 kHz with a wavelength about ten times or greater than a longest dimension of the navigational beacon antenna;

a second end configured to be in electrical communication with the navigational beacon antenna;

a first impedance element comprises an air core variable inductor electrically connected between the first end and the second end; and

a second impedance element comprises an air core variable inductor electrically connected between the first end and the electrical ground;

wherein each of the impedance elements being independent of capacitive circuit components.

17. The apparatus of claim 16, further comprising:

a sensor configured to estimate radio signal strength; and

a microcontroller configured to receive the estimated radio signal strength from the sensor and to transmit the estimated radio signal strength to the radio transmitter.

18. The apparatus of claim 17, wherein the sensor is a near-field signal strength detector.

19. The apparatus of claim 16, further comprising:

a signal generator configured to transmit a generated signal through the impedance matching L-network separate from the radio transmitter.

20. The apparatus of claim 19, wherein the signal generator is configured to limit the generated signal to a power level below a threshold that is harmful to humans.

21. The apparatus of claim 16, wherein the radio transmitter is configured to operate in frequency band of about 190 kilohertz to about 535 kilohertz.

22. A system for radio tuning adapted for use with an electrical ground, the system comprising:

an electrically short, navigational beacon antenna;

a radio transmitter, the radio transmitter generating a medium or high power signal between 190 kHz and 1800 kHz with a wavelength about ten times or greater than a longest dimension of the electrically short, navigational beacon antenna; and

an antenna tuning unit electrically connected between the electrically short, navigational beacon antenna and the radio transmitter, the antenna tuning unit comprising;

an impedance matching L-network comprising;

a first end configured to be in electrical communication with the radio transmitter;

a second end configured to be in electrical communication with the electrically short, navigational beacon antenna;

a first impedance element electrically connected between the first end and the second end; and

a second impedance element electrically connected between the first end and the electrical ground;

wherein each of the impedance elements comprises an air core variable inductor and wherein each of the impedance element being independent of capacitive circuit components.

23. The system of claim 22, further comprising:

a sensor configured to estimate radio signal strength; and

a microcontroller configured to receive the estimated radio signal strength from the sensor and to transmit the estimated radio signal strength to the radio transmitter.

24. The system of claim 23, further comprising:

a target radio signal strength; and

a closed loop controller configured to transmit a power adjustment signal to the radio transmitter based on the estimated radio signal strength received from the microcontroller and the target radio signal strength.

25. The system of claim 23, wherein the sensor is a near-field signal strength detector.

26. The system of claim 22, wherein the antenna tuning unit further comprises:

a signal generator configured to transmit a generated signal to the first end.

27. The system of claim 26, wherein the signal generator is configured to limit the generated signal to a power level below a threshold that is harmful to humans.

28. The system of claim 22, wherein the radio transmitter is configured to operate in a frequency band of about 190 kilohertz to about 535 kilohertz.

29. A method for tuning an antenna adapted for use with an electrical ground and using an impedance matching L-network electrically connected between the antenna and a radio transmitter, comprising the steps of:

providing the impedance matching L-network comprising;

a first end configured to receive a signal from the radio transmitter;

a second end electrically connected to the antenna;

at least one air core variable inductor electrically disposed between the first end and the second end; and

at least one air core variable inductor electrically disposed between the first end and the electrical ground; and

varying a value of at least one of the inductors to reduce signal reflection in the signal transmitted from the radio transmitter to the antenna;

wherein the radio transmitter generating a medium or high power signal between 190 kHz and 1800 kHz with a wavelength about ten times or greater than a longest dimension of the antenna.

30. The method of claim 29, wherein the antenna is electrically short.

31. The method of claim 29, further comprising the step of:

operating the impedance matching L-network between 190 kilohertz and 535 kilohertz.

32. An apparatus for tuning an electrically short, navigational beacon antenna adapted for use with a radio transmitter and an electrical ground, the apparatus comprising:

an impedance matching L-network being independent of capacitive circuit components, comprising;

a first end configured to be in electrical communication with a radio transmitter;

a second end configured to be in electrical communication with the electrically short, navigational beacon antenna;

at least one variable air inductor electrically connected between the first end and the second end; and

at least one variable air inductor electrically connected between the first end and the electrical ground;

wherein the radio transmitter generating a medium or high power signal between 190 kHz and 1800 kHz with a wavelength about ten times or greater than a longest dimension of the electrically short, navigational beacon.

33. The apparatus of claim 32, further comprising:

a sensor configured to estimate radio signal strength; and

a microcontroller configured to receive the estimated radio signal strength from the sensor and to transmit the estimated radio signal strength to the radio transmitter.

34. The apparatus of claim 33, wherein the sensor is a near-field signal strength detector.

35. The apparatus of claim 32, further comprising:

a signal generator configured to transmit a generated signal through the impedance matching L-network separate from the radio transmitter.

36. The apparatus of claim 35, wherein the signal generator is configured to limit the generated signal to a power level below a threshold that is harmful to humans.

37. The apparatus of claim 32, wherein the radio transmitter is configured to operate in frequency band of about 190 kilohertz to about 535 kilohertz.

38. A system for radio tuning adapted for use with an electrical ground, the system comprising:

an electrically short, navigational beacon antenna;

a radio transmitter, the radio transmitter generating a medium or high power signal between 190 kHz and 1800 kHz with a wavelength about ten times or greater than a longest dimension of the electrically short, navigational beacon; and

an antenna tuning unit electrically connected between the electrically short, navigational beacon antenna and the radio transmitter, the antenna tuning unit comprising;

an impedance matching L-network being independent of capacitive circuit components, comprising;

a first end configured to be in electrical communication with the radio transmitter;

a second end configured to be in electrical communication with the electrically short, navigational beacon antenna;

a variable air inductor electrically connected between the first end and the second end; and

a variable air inductor electrically connected between the first end and the electrical ground.

39. The system of claim 38, further comprising:

a sensor configured to estimate radio signal strength; and

a microcontroller configured to receive the estimated radio signal strength from the sensor and to transmit the estimated radio signal strength to the radio transmitter.

40. The system of claim 39, further comprising:

a target radio signal strength; and

a closed loop controller configured transmit a power adjustment signal to the radio transmitter based on the estimated radio signal strength received from the microcontroller and the target radio signal strength.

41. The system of claim 39, wherein the sensor is a near-field signal strength detector.

42. The system of claim 38, wherein the antenna tuning unit further comprises:

a signal generator configured to transmit a generated signal to the first end.

43. The system of claim 42, wherein the signal generator is configured to limit the generated signal to a power level below a threshold that is harmful to humans.

44. The system of claim 38, wherein the radio transmitter is configured to operate in a frequency band of about 190 kilohertz to about 535 kilohertz.

45. A method for tuning an electrically short, navigational beacon antenna adapted for use with an electrical ground and using an impedance matching L-network electrically connected between the electrically short, navigational beacon antenna and a radio transmitter, comprising the steps of:

providing the impedance matching L-network independent of capacitive circuit components comprising;

a first end configured to receive a signal from the radio transmitter, the radio transmitter generating a medium or high power signal between 190 kHz and 1800 kHz with a wavelength about ten times or greater than a longest dimension of the electrically short, navigational beacon antenna;

a second end electrically connected to the electrically short, navigational beacon antenna;

at least one variable air inductor electrically disposed between the first end and the second end; and

at least one variable air inductor electrically disposed between the first end and the electrical ground; and

varying a value of at least one of the inductors to reduce signal reflection in the signal transmitted from the radio transmitter to the electrically short, navigational beacon antenna.

46. The method of claim 45, further comprising the step of:

operating the impedance matching network between 190 kilohertz and 535 kilohertz.

47. A method for tuning an electrically short, navigational beacon antenna adapted for use with an electrical ground and using an impedance matching network electrically connected between the electrically short, navigational beacon antenna and a radio transmitter, comprising the steps of:

providing the impedance matching network comprising;

a first end configured to receive a signal from the radio transmitter the radio transmitter generating a medium or high power signal between 190 kHz and 1800 kHz with a wavelength about ten times or greater than a longest dimension of the electrically short, navigational beacon antenna;

a second end electrically connected to the electrically short, navigational beacon antenna;

a first impedance element electrically disposed between the first end and the second end; and

a second impedance element electrically disposed between the first end and the electrical ground;

wherein each of the impedance elements being independent of capacitive circuit components and including at least one air core variable inductor; and

varying a value of at least one of the impedance elements to reduce signal reflection in the signal transmitted from the radio transmitter to the electrically short, navigational beacon antenna.

48. The method of claim 47, further comprising the step of:

operating the impedance matching network between 190 kilohertz and 535 kilohertz.

49. The method of claim 47, further comprising the steps of:

sensing an estimated radio signal strength; and

transmitting the estimated radio strength to the radio transmitter.

50. The method of claim 49, wherein the sensor is a near-field signal strength detector.

51. The method of claim 49, further comprising the steps of:

generating a signal;

transmitting the generated signal through the impedance matching network; and

separating the generated signal from the radio transmitter.

52. The method of claim 49, further comprising the steps of:

determining a target radio signal strength; and

transmitting a power adjustment signal to the radio transmitter based on the estimated radio signal strength and the target radio signal strength.