Wireless signal distribution in a building HVAC system

• US 5,977,851 A
• Filed: 11/13/1997
• Issued: 11/02/1999
• Est. Priority Date: 11/13/1997
• Status: Expired due to Term

• Current Assignee: Carnegie Mellon University
• Original Assignee: Carnegie Mellon University
• Inventors: Diehl, Christopher P., Stancil, Daniel D.
• Primary Examiner(s): GENSLER, PAUL L
• Application Number:
  US08/969,399
• Time in Patent Office: 719 Days
• Field of Search: 333/239, 333/248, 333/249, 455/3.1, 455/6.3
• US Class Current: 333/248
• CPC Class Codes: H01P 3/12 Hollow waveguides H01P3/20 takes precedence

Abstract

The present invention is directed to a system for using the ductwork of a building for transmitting electromagnetic radiation. The system includes a device for introducing electromagnetic radiation into the ductwork such that the ductwork acts as a waveguide for the electromagnetic radiation. The system also includes a device for enabling the electromagnetic radiation to propagate beyond the ductwork. The present invention is also directed to a method for transmitting electromagnetic radiation using the ductwork of a building and a method for designing a system for transmitting electromagnetic radiation in the ductwork of a building.

Claims

1. A system for using the ductwork of a building for transmitting electromagnetic radiation, comprising:

a device for introducing electromagnetic radiation into the ductwork such that the ductwork acts as a waveguide for the electromagnetic radiation;

a device for enabling the electromagnetic radiation to propagate beyond the ductwork; and

a passive re-radiator positioned to re-radiate electromagnetic radiation around an obstacle.

2. The system of claim 1 wherein said device for introducing includes a coaxial to waveguide probe.

3. The system of claim 1 wherein said device for introducing includes an antenna.

4. The system of claim 1 wherein said device for enabling includes a coupler probe.

5. The system of claim 1 wherein said device for enabling includes an electrically transparent louver.

6. The system of claim 1 further comprising an electrically opaque reflector located at a point in the ductwork where the ductwork changes direction, said reflector for reflecting the electromagnetic radiation in a direction following the direction of the ductwork.

7. The system of claim 6 wherein said reflector is a metal sheet.

8. The system of claim 6 wherein said reflector is a wire grid.

9. The system of claim 1 further comprising a wire screen ground plane located in the ductwork adjacent to said device for introducing.

10. The system of claim 1 further comprising an electrically translucent damper located in the ductwork, said damper for deflecting air flow in the ductwork.

11. The system of claim 1 further comprising an absorber located in the ductwork, said absorber for minimizing multiple reflections of said electromagnetic radiation.

12. The system of claim 1 wherein said device for enabling includes a louver having at least one re-radiating structure.

13. The system of claim 1 further comprising an amplifier positioned to re-radiate the electromagnetic radiation.

14. The system of claim 13 wherein said amplifier includes a booster amplifier.

15. The system of claim 13 wherein said amplifier includes a directional receiving coupler, a directional transmitting coupler, and an electrically opaque screen interposed between said couplers.

16. A system for using the ductwork of a building for transmitting electromagnetic radiation, comprising:

a device for introducing electromagnetic radiation into the ductwork such that the ductwork acts as a waveguide for the electromagnetic radiation;

a device for enabling the electromagnetic radiation to propagate beyond the ductwork; and

an active re-radiator positioned to re-radiate electromagnetic radiation around an obstacle.

17. The system of claim 16 wherein said device for introducing includes a coaxial to waveguide probe.

18. The system of claim 16 wherein said device for introducing includes an antenna.

19. The system of claim 16 wherein said device for enabling includes a coupler probe.

20. The system of claim 16 wherein said device for enabling includes an electrically transparent louver.

21. The system of claim 16 further comprising an electrically opaque reflector located at a point in the ductwork where the ductwork changes direction, said reflector for reflecting the electromagnetic radiation in a direction following the direction of the ductwork.

22. The system of claim 21 wherein said reflector is a metal sheet.

23. The system of claim 21 wherein said reflector is a wire grid.

24. The system of claim 16 further comprising a wire screen ground plane located in the ductwork adjacent to said device for introducing.

25. The system of claim 16 further comprising an electrically translucent damper located in the ductwork, said damper for deflecting air flow in the ductwork.

26. The system of claim 16 further comprising an absorber located in the ductwork, said absorber for minimizing multiple reflections of said electromagnetic radiation.

27. The system of claim 16 wherein said device for enabling includes a louver having at least one re-radiating structure.

28. The system of claim 16 further comprising an amplifier positioned to re-radiate the electromagnetic radiation.

29. The system of claim 28 wherein said amplifier includes a booster amplifier.

30. The system of claim 29 wherein said amplifier includes a directional receiving coupler, a directional transmitting coupler, and an electrically opaque screen interposed between said couplers.

31. A system for using the ductwork of a building for transmitting electromagnetic radiation, comprising:

a device for introducing electromagnetic radiation into the ductwork such that the ductwork acts as a waveguide for the electromagnetic radiation;

a device for enabling the electromagnetic radiation to propagate beyond the ductwork; and

a wire screen ground plane located in the ductwork adjacent to said device for introducing.

32. The system of claim 31 wherein said device for introducing includes a coaxial to waveguide probe.

33. The system of claim 31 wherein said device for introducing includes an antenna.

34. The system of claim 31 wherein said device for enabling includes a coupler probe.

35. The system of claim 31 wherein said device for enabling includes an electrically transparent louver.

36. The system of claim 31 further comprising an electrically opaque reflector located at a point in the ductwork where the ductwork changes direction, said reflector for reflecting the electromagnetic radiation in a direction following the direction of the ductwork.

37. The system of claim 31 further comprising an electrically translucent damper located in the ductwork, said damper for deflecting air flow in the ductwork.

38. The system of claim 31 further comprising an absorber located in the ductwork, said absorber for minimizing multiple reflections of said electromagnetic radiation.

39. The system of claim 31 wherein said device for enabling includes a louver having at least one re-radiating structure.

40. The system of claim 31 further comprising an amplifier positioned to re-radiate the electromagnetic radiation.

41. A system for using the ductwork of a building for transmitting electromagnetic radiation, comprising:

a device for introducing electromagnetic radiation into the ductwork such that the ductwork acts as a waveguide for the electromagnetic radiation;

a device for enabling the electromagnetic radiation to propagate beyond the ductwork; and

an absorber located in the ductwork, said absorber for minimizing multiple reflections of the electromagnetic radiation.

42. The system of claim 41 further comprising an electrically opaque reflector located at a point in the ductwork where the ductwork changes direction, said reflector for reflecting the electromagnetic radiation in a direction following the direction of the ductwork.

43. The system of claim 41 further comprising an electrically translucent damper located in the ductwork, said damper for deflecting air flow in the ductwork.

44. The system of claim 41 wherein said device for enabling includes a louver having at least one re-radiating structure.

45. The system of claim 41 further comprising an amplifier positioned to re-radiate the electromagnetic radiation.

46. A system for using the ductwork of a building for transmitting electromagnetic radiation, comprising:

a device for introducing electromagnetic radiation into the ductwork such that the ductwork acts as a waveguide for the electromagnetic radiation;

a device for enabling the electromagnetic radiation to propagate beyond the ductwork; and

an amplifier positioned to re-radiate the electromagnetic radiation.

47. The system of claim 46 wherein said amplifier includes a booster amplifier.

48. The system of claim 46 wherein said amplifier includes a directional receiving coupler, a directional transmitting coupler, and an electrically opaque screen interposed between said couplers.

49. The system of claim 46 further comprising an electrically opaque reflector located at a point in the ductwork where the ductwork changes direction, said reflector for reflecting the electromagnetic radiation in a direction following the direction of the ductwork.

50. The system of claim 46 wherein said device for enabling includes a louver having at least one re-radiating structure.

51. A method for transmitting electromagnetic radiation using the ductwork of a building, comprising the steps of:

introducing the electromagnetic radiation into the ductwork such that the ductwork acts as a waveguide for the electromagnetic radiation;

enabling the electromagnetic radiation to exit the ductwork; and

passively re-radiating the electromagnetic radiation around an obstacle.

52. The method of claim 51 further comprising the step of reflecting the electromagnetic radiation in a direction following a change in direction of the ductwork.

53. The method of claim 51 further comprising the step of grounding portions of the ductwork to impede the transmission of the electromagnetic radiation.

54. The method of claim 51 further comprising the step of matching the impedance of the ductwork to the impedance of an electromagnetic radiation transmitter used for said introducing step.

55. The method of claim 51 further comprising the steps of:

receiving the electromagnetic radiation in the ductwork;

amplifying said received electromagnetic radiation; and

re-transmitting said amplified electromagnetic radiation.

56. A method for transmitting electromagnetic radiation using the ductwork of a building, comprising:

introducing the electromagnetic radiation into the ductwork such that the ductwork acts as a waveguide for the electromagnetic radiation;

enabling the electromagnetic radiation to exit the ductwork; and

actively re-radiating the electromagnetic radiation around an obstacle.

57. The method of claim 56 further comprising reflecting the electromagnetic radiation in a direction following a change in direction of the ductwork.

58. The method of claim 56, further comprising grounding portions of the ductwork to impede the transmission of the electromagnetic radiation.

59. The method of claim 56, further comprising matching the impedance of the ductwork to the impedance of an electromagnetic radiation transmitter used for said introducing.

60. The method of claim 56, further comprising:

receiving the electromagnetic radiation in the ductwork;

amplifying said received electromagnetic radiation; and

re-transmitting said amplified electromagnetic radiation.

61. A method for transmitting electromagnetic radiation using the ductwork of a building, comprising:

introducing the electromagnetic radiation into the ductwork such that the ductwork acts as a waveguide for the electromagnetic radiation;

enabling the electromagnetic radiation to exit the ductwork; and

grounding portions of the ductwork to impede the transmission of the electromagnetic radiation.

62. A method for transmitting electromagnetic radiation using the ductwork of a building, comprising:

introducing the electromagnetic radiation into the ductwork such that the ductwork acts as a waveguide for the electromagnetic radiation;

enabling the electromagnetic radiation to exit the ductwork;

receiving the electromagnetic radiation in the ductwork;

amplifying said received electromagnetic radiation; and

re-transmitting said amplified electromagnetic radiation.