Antenna system with parasitic element and associated method

• US 20060227062A1
• Filed: 04/06/2005
• Published: 10/12/2006
• Est. Priority Date: 04/06/2005
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Lindsey, Phillip A., Francque, Craig
• Granted Patent: US 7,382,330 B2
• Time in Patent Office: Days
• US Class Current: 343/893
• CPC Class Codes: H01Q 1/523 between antennas of an array
• CPC Class Codes: H01Q 19/32 the primary active element being end-fed and elongated

Abstract

An antenna system comprises a parasitic element, which is an electrically tuned structural element, installed between antennas to reduce or eliminate antenna-to-antenna coupled electromagnetic interference by emitting destructive interference in the direction from one antenna to another antenna. The antenna system comprises a first antenna operating at a first wavelength, a second antenna operating at a second wavelength, and a parasitic element located between the first antenna and the second antenna for reducing the amplitude of signals from the first antenna that would otherwise create electromagnetic interference in a receiver connected to the second antenna. The parasitic element is typically spaced from the first antenna by a distance substantially equal to one quarter of the first wavelength. The parasitic element generally has a height that is greater than the height of the first antenna.

Claims

1. An antenna system comprising:

a first antenna operating at a first wavelength;

a second antenna operating at a second wavelength; and

a parasitic element located between the first antenna and the second antenna for reducing the amplitude of signals from the first antenna that would otherwise create electromagnetic interference in a receiver connected to the second antenna.

2. The antenna system of claim 1, wherein the parasitic element has a height that is greater than a height of the first antenna.

3. The antenna system of claim 2, wherein the parasitic element is spaced from the first antenna by a distance substantially equal to one quarter of the first wavelength.

4. The antenna system of claim 1, wherein the parasitic element has a height that is greater than a height of the second antenna.

5. The antenna system of claim 4, wherein the parasitic element is spaced from the second antenna by a distance substantially equal to one quarter of the second wavelength.

6. The antenna system of claim 1, wherein the parasitic element is a first parasitic element, wherein the antenna system further comprises a second parasitic element, wherein the first parasitic element has a height that is greater than a height of the first antenna, and wherein the second parasitic element has a height that is greater than a height of the second antenna.

7. The antenna system of claim 6, wherein the first parasitic element is spaced from the first antenna by a distance substantially equal to one quarter of the first wavelength and wherein the second parasitic element is spaced from the second antenna by a distance substantially equal to one quarter of the second wavelength.

8. The antenna system of claim 1, wherein the first wavelength is the same as the second wavelength.

9. The antenna system of claim 1, wherein the first wavelength is different than the second wavelength.

10. The antenna system of claim 1, wherein the first antenna is operating at a plurality of wavelengths.

11. The antenna system of claim 1, wherein the parasitic element comprises a cylinder.

12. The antenna system of claim 1, wherein the parasitic element has a planar shape selected from the group comprising rectangular and trapezoidal.

13. The antenna system of claim 12, wherein the parasitic element is photo-etched on a dielectric substrate.

14. The antenna system of claim 1, further comprising a plurality of antennas operating at a plurality of respective wavelengths and a plurality of parasitic elements located between at least two of the plurality of antennas and the second antenna.

15. A vehicle system comprising:

a vehicle body;

a first antenna mounted on the vehicle body operating at a first wavelength;

a second antenna mounted on the vehicle body operating at a second wavelength; and

a parasitic element mounted on the vehicle body located between the first antenna and the second antenna for reducing the amplitude of signals from the first antenna that would otherwise create electromagnetic interference in a receiver connected to the second antenna.

16. The vehicle system of claim 15, wherein the vehicle body is an aircraft.

17. The vehicle system of claim 15, wherein the parasitic element has a height that is greater than a height of the first antenna;

and wherein the parasitic element is spaced from the first antenna by a distance substantially equal to one quarter of the first wavelength.

18. The vehicle system of claim 15, wherein the parasitic element parasitic element has a height that is greater than a height of the second antenna;

and wherein the parasitic element is spaced from the second antenna by a distance substantially equal to one quarter of the second wavelength.

19. A method of reducing the amplitude of signals from a first antenna that would otherwise create electromagnetic interference in a receiver connected to a second antenna, the method comprising:

positioning a parasitic element between the first antenna and the second antenna, wherein the parasitic element is responsive to the signals from the first antenna to emit destructive interference in the direction of the second antenna.

20. The method of claim 19, wherein the parasitic element has a height that is greater than a height of the first antenna, and wherein the parasitic element is positioned a distance from the first antenna substantially equal to one quarter of a wavelength at which the first antenna is operating.

21. The antenna system of claim 19, wherein the parasitic element has a height that is greater than a height of the second antenna, and wherein the parasitic element is positioned a distance from the second antenna substantially equal to one quarter of a wavelength at which the second antenna is operating.

22. The method of claim 20, wherein the parasitic element is a first parasitic element, wherein the method further comprises positioning a second parasitic element between the first antenna and the second antenna, wherein the second parasitic element is responsive to the signals from the first antenna to emit destructive interference in the direction of the second antenna, wherein the second parasitic element has a height that is greater than a height of the second antenna, and wherein the second parasitic element is spaced from the second antenna by a distance substantially equal to one quarter of a wavelength at which the second antenna is operating.