Arrangement relating to antennas and a method of manufacturing the same

• US 6,529,174 B2
• Filed: 12/21/2000
• Issued: 03/04/2003
• Est. Priority Date: 12/21/1999
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Hemmendorff, Erik, Byström, Daniel, Stjernman, Anders
• Primary Examiner(s): PHAN, THO GIA
• Application Number:
  US09/741,013
• Publication Number:
  US 20010028328A1
• Time in Patent Office: 803 Days
• Field of Search: H01/Q 1.502, 343/700.MS, 343/753, 343/754, 343/755, 343/756, 343/779, 343/781.P, 343/778, 343/795, 343/909
• US Class Current: 343/909
• CPC Class Codes: H01Q 15/0013 said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
• CPC Class Codes: H01Q 19/10 using reflecting surfaces
• CPC Class Codes: H01Q 21/06 Arrays of individually energised antenna units similarly polarised and spaced apart
• CPC Class Codes: H01Q 3/46 Active lenses or reflecting arrays

Abstract

The present invention refers to an arrangement in an antenna, the arrangement comprising: an electrically thin microwave phasing structure including a support member, a reflective arrangement for reflecting microwaves within a frequency operating band and supported by said supporting member, and a phasing arrangement of electromagnetically-loading structures, said electromagnetically-loading structures being interspaced from each other and disposed at a distance from said reflective arrangement by a support matrix to provide said emulation of said desired reflective surface of selected geometry. The electromagnetically-loading structures are arranged on at least two substrate layers in at least two planes.

Claims

1. A microwave phasing structure for electromagnetically emulating a desired reflective surface of selected geometry in order to achieve phase-coherency of an incident electromagnetic wave at a focal point, comprising:

a multi-layer support member;

a reflective member supported by said support member, configured to reflect microwaves within a predetermined operating frequency band; and

a phasing arrangement of electromagnetically-loading structures that are interspaced from each other and disposed at a distance from said reflective member by the support member so as to provide the emulation of the desired reflective surface of selected geometry, wherein each electromagnetically-loading structure comprises a plurality of elements, each of said elements being arranged in different planes, arranged on different layers of the multilayer support member and insulated one from the others by said support member.

2. The microwave phasing structure of claim 1, wherein the electromagnetically-loading structures are dipoles.

3. The microwave phasing structure of claim 2, wherein at least one element of each dipole is arranged on one side of each layer of said support member in parallel with at least one element of all other dipoles.

4. The microwave phasing structure of claim 2, wherein pairs of the dipoles are arranged in a substantially cross-shaped configuration each having a first element on one plane insulated from a substantially orthogonally second element arranged on a different plane.

5. The microwave phasing structure of claim 2, wherein the dipoles have different sizes.

6. The microwave phasing structure of claim 2, wherein the dipoles have different shapes.

7. The microwave phasing structure of claim 2, further comprising a feeder having a phase center, wherein a length of each dipole is a function of a distance from the phase center of the feeder to a point on a plane that is perpendicular to the incident electromagnetic wave.

8. The microwave phasing structure of claim 7, wherein each dipole is further configured to emulate an area of the desired reflective surface of selected geometry by providing a phase shift of the incident electromagnetic wave, the required phase shift being calculated according to:

phase shift=phase dipole+phase adjust

wherein plane phase=phase length+phase shift, and

wherein plane phase is the phase at the perpendicular plane.

9. The microwave phasing structure of claim 8, wherein the phase adjust is determined so that a minimized number of dipole phase shifts are included in a phase gap.

10. The microwave phasing structure of claim 7, wherein said microwave phasing structure is a component of a center-fed antenna with a tilted main lobe and wherein the phase length is calculated according to:

$\mathrm{Phaselength}=(\sqrt{z^2+x^2+y^2)}·<br><br>\frac{2<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\pi <br><br>}}{\mathrm{\lambda <br><br>}}$

where x, y and z are coordinates in a Cartesian coordinate system with the origin in the phase center of the feeder and λ

is the wavelength of the radiated electromagnetic wave.

11. The microwave phasing structure of claim 7, wherein said microwave phasing structure is a component of an offset-fed broad side antenna and wherein the phase length is calculated according to:

$\mathrm{Phaselength}=\left(\sqrt{z^2+x^2+y^2)}+x·<br><br>\sin <br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\phi <br><br>}\right)·<br><br>\frac{2<br><br>\mathrm{\pi <br><br>}}{\mathrm{\lambda <br><br>}}$

where φ

is the angle at which the main lobe is tilted.

12. The microwave phasing structure of claim 7, wherein said microwave phasing structure is a component in an arrangement selected from a group including of a Point-to-Point antenna and a Point-to-Multipoint antenna and wherein the phase length is calculated according to:

$\mathrm{Phaselength}=\left(\sqrt{\left(z^2+{\left(x-x_{\mathrm{offset}}\right)}^2+{\left(y-y_{\mathrm{offset}}\right)}^2\right)}+x·<br><br>\sin <br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\phi <br><br>}}^{\mathrm{\prime <br><br>}}\right)·<br><br>\frac{2<br><br>\mathrm{\pi <br><br>}}{\mathrm{\lambda <br><br>}}$

wherein ${\mathrm{\theta <br><br>}}^{\mathrm{\prime <br><br>}}=a<br><br>\text{\hspace{1em}<br><br>}<br><br>\cos <br><br>\text{\hspace{1em}<br><br>}<br><br>\left(\frac{z·<br><br>\cos <br><br>\text{\hspace{1em}<br><br>}<br><br>\left(\mathrm{\alpha <br><br>}\right)-y·<br><br>\sin <br><br>\left(\mathrm{\alpha <br><br>}\right)}{r}\right)$${\mathrm{\phi <br><br>}}^{\mathrm{\prime <br><br>}}=a<br><br>\text{\hspace{1em}<br><br>}<br><br>\tan <br><br>\text{\hspace{1em}<br><br>}<br><br>\left(\frac{z·<br><br>\cos <br><br>\text{\hspace{1em}<br><br>}<br><br>\left(\mathrm{\alpha <br><br>}\right)+y·<br><br>\sin <br><br>\text{\hspace{1em}<br><br>}<br><br>\left(\mathrm{\alpha <br><br>}\right)}{r}\right).$

13. The microwave phasing structure of claim 1, wherein pairs of elements of the electromagnetically-loading structures are arranged in a substantially cross-shaped configuration each having a first element on one plane insulated from a substantially orthogonally directed second element arranged on a different plane.

14. The microwave phasing structure of claim 13, wherein the first elements of the electromagnetically-loading structures are arranged in parallel with respect to one another and at an angle with respect to the sides of the reflective member.

15. The microwave phasing structure of claim 1, wherein the electromagnetically-loading structures have different sizes.

16. The microwave phasing structure of claim 1, wherein the electromagnetically-loading structures have different shapes.

17. The microwave phasing structure of claim 1, wherein said microwave phasing structure is a component of a center-fed broad side antenna.

18. The microwave phasing structure of claim 1, wherein said microwave phasing structure is a component of a center-fed antenna with a tilted main lobe.

19. The microwave phasing structure of claim 1, wherein said microwave phasing structure is a component of an offset-fed broad side antenna.

20. The microwave phasing structure of claim 1, wherein said microwave phasing structure is a component in an arrangement selected from a group including a Point-to-Point antenna and a Point-to-Multipoint antenna.

21. An antenna comprising an electromagnetic feeding arrangement and a reflector arrangement, said reflector arrangement comprising:

a microwave phasing structure supported by a multilayer support member;

a reflective member for reflecting microwaves within a frequency operating band; and

a phasing arrangement of electromagnetically-loading structures that are interspaced from each other and disposed at a distance from said reflective arrangement by the support member and configured to provide emulation of a desired reflective surface of selected geometry and wherein each electromagnetically-loading structure comprises a plurality of elements, each of said elements being arranged in different planes, arranged on different layers of the support member and insulated one from the others by said support member.

22. The antenna of claim 21, wherein the electromagnetic feeding arrangement comprises at least one feeder for each plane.

23. The antenna of claim 21, further comprising an additional reflective member facing said reflector arrangement.

24. The antenna of claim 23, wherein said reflective member is arranged to reflect vertically or horizontally polarized electromagnetic waves and said additional reflective member is arranged to rotate and transform the reflected waves to horizontal or vertical polarization.

25. A microwave phasing structure for electromagnetically emulating a desired reflective surface of selected geometry in order to achieve phase-coherency of an incident electromagnetic wave at a focal point, comprising:

a phasing arrangement including a plurality of electromagnetically-loading structures, each of said electromagnetically-loading structures comprising a pair of elements, each of said elements being spaced apart in different planes, arranged on different layers and insulated one from the other.

26. The microwave phasing structure of claim 25, wherein said elements of each of said pair of elements are cross-oriented and short-free with respect to one another.

27. A method of producing a microwave phasing structure for electromagnetically emulating a desired reflective surface of selected geometry in order to achieve phase-coherency of an incident electromagnetic wave at a focal point that includes a phasing arrangement of a plurality of electromagnetically-loading structures, each of said electromagnetically-loading structures comprising a pair of elements, each of said elements being spaced apart in different planes and insulated one from the other, comprising:

arranging the electromagnetically-loading structures on different layers;

determining characteristics of an antenna employing a reflector;

calculating a distance between a feeder and each electromagnetically-loading structure with respect to the characteristics of the antenna;

calculating a phase shift required to be provided by each electromagnetically-loading structure; and

using said calculated phase shift for calculating the length of the each electromagnetically-loading structure.

28. The method of claim 27, wherein determining characteristics of the antenna employing the reflector further comprises determining antenna size, antenna type, operating frequency band, feeder type, and feeder size.

29. The method of claim 27, wherein calculating the phase shift required to be provided by each electromagnetically-loading structure further comprises analyzing the phasing arrangement comprising a microstrip dipole surrounded by an infinite number of identical dipoles.

30. The method of claim 27, wherein calculating the phase shift required to be provided by each electromagnetically-loading structure further comprises analyzing the phasing arrangement comprising dual layer dichroic structures, which consist of two parallel metallic screens separated by at least one dielectric layer.

31. The method of claim 27, wherein calculating the phase shift required to be provided by each electromagnetically-loading structure further comprises analyzing the phasing arrangement comprising a single grating surrounded by a number of dielectric layers that are electrically proximate to the grating.