High gain antenna for microwave frequencies

• US 7,023,386 B2
• Filed: 03/15/2004
• Issued: 04/04/2006
• Est. Priority Date: 03/15/2004
• Status: Active Grant

• Current Assignee: ELTA Systems Limited (Government of Israel)
• Original Assignee: ELTA Systems Limited (Government of Israel)
• Inventors: Habib, Laurent, Samson, Claude
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US10/800,019
• Publication Number:
  US 20050200527A1
• Time in Patent Office: 750 Days
• Field of Search: 343/795, 343/793, 343/806, 343/803, 343/810, 343/700.MS, 343/850, 343/853
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 21/062 using dipole aerials; H01Q21/067, H01Q21/068 take precedence
• CPC Class Codes: H01Q 9/0428 radiating a circular polarised wave
• CPC Class Codes: H01Q 9/065 Microstrip dipole antennas patch antenna H01Q9/0407
• CPC Class Codes: H01Q 9/26 with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength resonant loop antennas H01Q7/00
• CPC Class Codes: H01Q 9/27 Spiral antennas

Abstract

A microwave antenna for transmitting and/or receiving electromagnetic waves of at least one predefined frequency and a predefined polarization, the antenna comprises a support with upper and lower faces; at least one pair of substantially identical upper and lower radiating elements disposed on said upper and lower faces; in each pair of said radiating element in the upper face and the corresponding radiating element in the lower face, the phase center of the lower radiating element substantially coincides with the phase center of the upper radiating element.

Claims

1. A microwave antenna for transmitting and/or receiving electromagnetic waves of at least one predefined frequency and a predefined polarization, the antenna comprising a support with upper and lower faces and at least one pair of substantially identical upper and lower radiating elements disposed on said upper and lower faces;

each radiating element is capable of transmitting and/or receiving electromagnetic waves of said predefined polarization with a phase center located at a predefined position;

in each pair, the phase center of the lower radiating element substantially coincides with the phase center of the upper radiating element.

2. An antenna according to claim 1 wherein said support is conformal.

3. An antenna according to claim 1 wherein said support is substantially planar.

4. An antenna according to claim 1 wherein said predefined polarization is a circular polarization, and wherein each of said radiating elements is capable of radiating electromagnetic waves of a circular polarization.

5. An antenna according to claim 4 wherein said radiating elements comprising bend-shaped elements.

6. An antenna according to claim 4 wherein said bend-shape is an L-shape.

7. An antenna according to claim 6 wherein said L-shape having first and second branches and a feed point located on said second branch such that the electric current generated in the second branch is phase delayed in 90°

with respect to the electric current generated in the first branch.

8. An antenna according to claim 7 wherein said L-shape having an X branch and an orthogonal Y branch, and wherein:

the length A of the X branch and the length B of the Y branch are substantially identical and depend on said predefined frequency according to the relation;

A, B=K₁ λ

₀, K₁ is in the range of 0.3 to 0.35;

the widths C of the X and Y branches depend on said predefined frequency according to the relation;

C=K₂ λ

₀, K₂ is in the range of 0.10 to 0.20;

the length D between the X branch of said upper radiating element and the X branch of said lower radiating element depend on said predefined frequency according to the relation;

D=K₃ λ

₀, K₃ is in the range of 0.3 to 0.6;

the length E between the Y branch of said upper radiating element and the Y branch of said lower radiating element depend on said predefined frequency according to the relation;

E=K₄ λ

₀, K₄ is in the range of 0.3 to 0.6;

wherein λ

₀ is the wavelength of said predefined frequency in air.

9. An antenna according to claim 1 wherein said pair of substantially identical upper and lower radiating elements disposed on said upper and lower faces yields gain increase in the range of 1 dB–

3 dB.

10. An antenna for transmitting and/or receiving electromagnetic waves of at least one predefined frequency and a predefined polarization, the antenna comprising a multi-layered substrate structure having a dielectric substrate with upper and lower faces;

at least one pair of substantially identical upper and lower radiating elements disposed on said upper and lower faces of the dielectric substrate;

each radiating element is capable of transmitting and/or receiving electromagnetic waves of said predefined polarization with a phase center located at a predefined position;

each radiating element comprising a radiating element and a transmission line, the geometrical dimensions of which depend on said predefined frequency;

in each pair;

the transmission lines of the upper and lower elements overlay each other;

the radiating elements of the upper and lower elements are located oppositely to each other with respect to a plane perpendicular to the plane of the dielectric substrate, such that the phase center of the lower radiating element substantially coincides with the phase center of the upper radiating element.

11. An antenna according to claim 10 wherein said multi-layered substrate structure is conformal.

12. An antenna according to claim 10 wherein said multi-layered substrate structure is substantially planar.

13. An antenna according to claim 10 wherein said predefined polarization is a circular polarization, and wherein each of said radiating elements is capable of radiating electromagnetic waves of a circular polarization.

14. An antenna according to claim 13 wherein said radiating elements comprising radiating elements having a substantial L-shape.

15. An antenna according to claim 13 wherein said radiating elements comprising radiating elements having an L-shape.

16. An antenna according to claim 15 wherein said L-shape having first and second branches and a feed point located on said second branch such that the electric current generated in the second branch is phase delayed at 90°

with respect to the electric current generated in the first branch.

17. An antenna according to claim 10 wherein said pair of substantially identical upper and lower radiating elements disposed on said upper and lower faces yields gain increase in the range of 1 dB–

3 dB.

18. A method for providing a planar antenna for transmitting and/or receiving electromagnetic waves of at least one predefined frequency and a predefined polarization, the antenna having a dielectric substrate with upper and lower faces;

at least one pair of substantially identical upper and lower radiating elements disposed on said upper and lower faces of the dielectric substrate;

each radiating element is capable of transmitting and/or receiving electromagnetic waves of said predefined polarization with a phase center located at a predefined position;

said radiating elements comprising first and second radiating element branches, the method comprising;

determining the planar arrangement and the geometrical dimensions of said first and second radiating element branches in accordance with said predefined polarization and said at least one predefined frequency;

associating each of the radiating elements in the upper face with a corresponding radiating element in the lower face, such that the phase center of the lower radiating element substantially coincides with the phase center of the upper radiating element.

19. A method according to claim 18 wherein said predefined polarization is a circular polarization and wherein each of said radiating elements is capable of radiating electromagnetic waves of a circular polarization.

20. A method according to claim 19 wherein said radiating elements comprise radiating elements having a bend-shape.

21. A method according to claim 20 wherein said bend-shape is an L-shape.

22. A method according to claim 21 wherein said L-shape having first and second branches and a feed point located on said second branch such that the electric current generated in the second branch is phase delayed at 90°

with respect to the electric current generated in the first branch.

23. A method according to claim 21 wherein said L-shape having an X branch and an orthogonal Y branch, and wherein:

the length A of the X branch and the length B of the Y branch are substantially identical and depend on said predefined frequency according to the relation;

A, B=K₁ λ

₀, K₁ is in the range of 0.3 to 0.35;

the widths C of the X and Y branches depend on said predefined frequency according to the relation;

C=K₂ λ

₀, K₂ is in the range of 0.10 to 0.20;

the length D between the X branch of said upper radiating element and the X branch of said lower radiating element depend on said predefined frequency according to the relation;

D=K₃ λ

₀, K₃ is in the range of 0.3 to 0.6;

the length E between the Y branch of said upper radiating element and the Y branch of said lower radiating element depend on said predefined frequency according to the relation;

E=K₄ λ

₀, K₄ is in the range of 0.3 to 0.6;

wherein λ

₀ is the wavelength of said predefined frequency in air.