HIGH PERFORMANCE LOW PROFILE ANTENNAS

• US 20120274528A1
• Filed: 02/13/2012
• Published: 11/01/2012
• Est. Priority Date: 02/11/2011
• Status: Active Grant

• Current Assignee: Antenum, Inc.
• Original Assignee: Ami Research & Development, LLC
• Inventors: Apostolos, John T., Feng, Judy, Mouyos, William, McMahon, Benjamin
• Granted Patent: US 9,806,425 B2
• Time in Patent Office: Days
• US Class Current: 343/785
• CPC Class Codes: H01Q 13/20 Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave
• CPC Class Codes: H01Q 13/22 Longitudinal slot in boundary wall of waveguide or transmission line H01Q13/203 takes precedence
• CPC Class Codes: H01Q 13/24 constituted by a dielectric or ferromagnetic rod or pipe H01Q13/28 takes precedence
• CPC Class Codes: H01Q 13/28 comprising elements constituting electric discontinuities and spaced in direction of wave propagation, e.g. dielectric elements or conductive elements forming artificial dielectric
• CPC Class Codes: H01Q 21/0068 Dielectric waveguide fed arrays
• CPC Class Codes: H01Q 21/068 using parallel coplanar travelling wave or leaky wave aerial units H01Q21/065 takes precedence

Abstract

A leaky travelling wave array of elements provide a broadband radio frequency antenna.

Claims

1. An antenna comprising:

a waveguide having a top surface, a bottom surface, a load end, and an excitation end; and

a continuous tapered wedge element disposed on the waveguide to cause the waveguide to operate in a leaky mode.

2. The apparatus of claim 1 wherein a coupling layer is disposed between the waveguide and the wedge element to provide coupling between the waveguide and the wedge element that varies as a function of a distance along a main axis of the waveguide.

3. The apparatus of claim 2 wherein the coupling layer decreases in thickness with distance from the excitation end.

4. The apparatus of claim 1 wherein the coupling layer further reduces dispersion for radiation incident upon the wedge element.

5. The apparatus of claim 1 wherein the wedge element loosely couples to waves propagating within the waveguide, casing the waveguide to leak power along a portion of its length.

6. The apparatus of claim 1 wherein the waveguide is a two dimensional slab and the scattering wedge is disposed over the top surface of the slab.

7. The antenna of claim 1 further comprising a wavelength correction element that provides linear delay to incident energy received by the waveguide.

8. The apparatus of claim 7 wherein the correction element is a set of discrete features embedded in the waveguide and having a periodically modulated spacing.

9. The apparatus of claim 7 wherein the correction element is a material layer that tapers from a thin section to a thick section.

10. The apparatus of claim 9 wherein the thick section is located near the excitation end.

11. The apparatus of claim 1 wherein the waveguide further comprises multiple waveguide layers of at least two different dielectric constants (ε

_r).

12. The apparatus of claim 11 wherein the multiple waveguide layers provide frequency selective surfaces (FSS) to maintain receiving beam shape and direction constant with frequency.

13. The apparatus of claim 12 wherein the FSS have chirped spacing.

14. The apparatus of claim 11 wherein gaps are disposed between the waveguide layers.

15. The apparatus of claim 14 additionally comprising a control element for controlling a spacing of the gaps between layers.

16. The apparatus of claim 15 wherein the control element is a piezoelectric or electroactive control.

17. The apparatus of claim 15 wherein the gap size is controlled to electrically scan a beam pattern of the antenna.

18. The apparatus of claim 1 further comprising a quadratic phase weight disposed adjacent the waveguide.

19. The apparatus of claim 18 wherein the quadratic phase weight is provided by a material layer having a thickness tapering from the detection end to the collection end.

20. The apparatus of claim 18 wherein the quadratic phase weight comprises sub-surface elements within the waveguide.

21. The apparatus of claim 20 wherein the sub surface elements are varied in length, spacing, and/or depth within the waveguide.

22. The apparatus of claim 20 wherein the sub surface elements are located deep enough within the waveguide so as to not radiate outside the waveguide.