Aperture-fed, stacked-patch antenna assembly
Directive gain antenna elements implemented with an aperture-fed patch array antenna assembly are described. A feed network for the aperture-fed patch array may include offset apertures and may also include meandering feed lines. Scalable aperture shapes and orientations that can be used with antennas operating at any frequency and with dual orthogonal polarizations are also disclosed. Directive gain antenna elements implemented with arrays of orthogonal reflected dipoles are also described with optimal feed networks and parasitic elements to achieve desired directive gain characteristics. Such arrayed dipole antennas feature dual orthogonal polarizations with assembly tabs that lower cost and improve reliability. Backhaul radios that incorporate said antennas are also disclosed.
1. An antenna assembly comprising: a first substrate comprising: a plurality of first substrate conductive patch elements; a second substrate comprising: a first layer with at least a conductive ground plane and a plurality of pairs of apertures, wherein a number of the plurality of pairs of apertures is equal to a number of the plurality of first substrate conductive patch elements; and a second layer with at least a first transmission line feed network coupled to a first feed point and a second transmission line feed network coupled to a second feed point; a third substrate comprising: a plurality of third substrate conductive patch elements, wherein a number of the plurality of third substrate conductive patch elements is equal to the number of the plurality of first substrate conductive patch elements; a first spacer interposed between the third substrate and the second substrate, the first spacer comprising a dielectric material and at least one first spacer opening in the dielectric material, wherein the dielectric material is absent within the at least one first spacer opening; and a second spacer interposed between the first substrate and the third substrate, the second spacer comprising a dielectric material and at least one second spacer opening in the dielectric material, wherein the dielectric material is absent within the at least one second spacer opening; wherein a first feedline portion of the first transmission line feed network crosses over a rectangular aperture body of the first aperture of each pair of the plurality of pairs of apertures in a first direction for each first aperture that excites each respective stacked resonant radiating antenna element formed amongst each respective one of the plurality of first substrate conductive patch elements, each respective one of the plurality of third substrate conductive patch elements and the conductive ground plane for said stacked resonant radiating antenna elements arranged in a first column of said stacked resonant radiating antenna elements and a second feedline portion of the first transmission line feed network crosses over a rectangular aperture body of the first aperture of each pair of the plurality of pairs of apertures in a second direction for each first aperture that excites each respective stacked resonant radiating antenna element formed amongst each respective one of the plurality of first substrate conductive patch elements, each respective one of the plurality of third substrate conductive patch elements and the conductive ground plane for said stacked resonant radiating antenna elements arranged in a second column of said stacked resonant radiating antenna elements, and wherein the second direction is opposite to the first direction; wherein a third feedline portion of the second transmission line feed network crosses over a rectangular aperture body of the second aperture of each pair of the plurality of pairs of apertures in a third direction for each second aperture that excites each respective stacked resonant radiating antenna element formed amongst each respective one of the plurality of first substrate conductive patch elements, each respective one of the plurality of third substrate conductive patch elements and the conductive ground plane for said stacked resonant radiating antenna elements arranged in the first column of said stacked resonant radiating antenna elements and a fourth feedline portion of the second transmission line feed network crosses over a rectangular aperture body of the second aperture of each pair of the plurality of pairs of apertures in a fourth direction for each second aperture that excites each respective stacked resonant radiating antenna element formed amongst each respective one of the plurality of first substrate conductive patch elements, each respective one of the plurality of third substrate conductive patch elements and the conductive ground plane for said stacked resonant radiating antenna elements arranged in the second column of said stacked resonant radiating antenna elements, and wherein the third direction is the same as the fourth direction.
2. The antenna assembly of claim 1 , wherein the first substrate is formed from a printed circuit board.
3. The antenna assembly of claim 1 , wherein the second substrate is formed from a printed circuit board.
4. The antenna assembly of claim 3 , wherein the second substrate is formed from a printed circuit board comprising more than two layers.
5. The antenna assembly of claim 4 , wherein the first transmission line feed network and the second transmission line feed network each comprise striplines.
6. The antenna assembly of claim 1 , wherein the first transmission line feed network and the second transmission line feed network each comprise microstrip lines.
7. The antenna assembly of claim 1 , wherein the first feed point and the second feed point are each coupled to respective components on an outside layer of the second substrate.
8. The antenna assembly of claim 7 , wherein the respective components are at least one of an RF bandpass filter or a low noise amplifier within a receiver.
9. The antenna assembly of claim 1 , further comprising a plurality of fasteners to hold the first substrate, the second substrate, the third substrate, the first spacer and the second spacer together.
10. The antenna assembly of claim 1 , wherein the first aperture of each respective pair of the plurality of pairs of apertures is oriented relative to the second aperture of each respective pair of the plurality of pairs of apertures in a T-shape.
11. The antenna assembly of claim 1 , wherein the plurality of first substrate conductive patch elements is arranged in a first array with a plurality of first substrate rows wherein each first substrate row comprises at least one first substrate conductive patch element, and wherein the plurality of third substrate conductive patch elements is arranged in a third array with a plurality of third substrate rows wherein each third substrate row comprises at least one third substrate conductive patch element.
12. The antenna assembly of claim 1 , wherein the plurality of first substrate conductive patch elements is arranged in a first array with a plurality of first substrate rows and one or more first substrate columns wherein each first substrate row comprises a number of first substrate conductive patch elements equal to the number of first substrate columns, and wherein the plurality of third substrate conductive patch elements is arranged in a third array with a plurality of third substrate rows and one or more third substrate columns wherein each third substrate row comprises a number of third substrate conductive patch elements equal to the number of third substrate columns.
13. The antenna assembly of claim 12 , wherein the number of first substrate columns is equal to two, and wherein the number of third substrate columns is equal to two.
14. The antenna assembly of claim 13 , wherein the second feedline portion is electrically longer than the first feedline portion by a distance equivalent to 180 degrees in phase at a target operating frequency for the antenna assembly.
15. The antenna assembly of claim 11 , wherein each of the first transmission line feed network and the second transmission line feed network comprises at least one meandering line portion.
16. The antenna assembly of claim 15 , wherein each meandering line portion comprises one or more bends, and wherein an electrical length of each meandering line portion matches a group delay from the respective first or second feed point to at least one of the respective first or second apertures with that of another group delay from the respective first or second feed point to at least one other of the respective first or second apertures.
17. The antenna assembly of claim 11 , wherein each of the first transmission line feed network and the second transmission line feed network comprises at least one tunable element.
18. The antenna assembly of claim 17 , wherein an input signal applied to at least one tunable element adjusts at least one characteristic of the antenna assembly, said characteristic being at least one selected from the group consisting of a far-field radiation pattern, a coupling between the first feed point and the second feed point, and a coupling to one or more nearby antennas.
19. The antenna assembly of claim 1 , wherein the second layer of the second substrate contains two feed points and two transmission line feed networks.
20. The antenna assembly of claim 1 , wherein at least one of the plurality of third substrate conductive patch elements is located on a surface of the third substrate facing the at least one first spacer opening.
21. The antenna assembly of claim 1 , wherein at least one of the plurality of third substrate conductive patch elements is located on a surface of the third substrate facing the at least one second spacer opening.
22. The antenna assembly of claim 1 , wherein at least one of the plurality of third substrate conductive patch elements is located on both surfaces of the third substrate.
23. The antenna assembly of claim 1 , wherein the number of the plurality of first substrate conductive patch elements located on the first substrate equals a number of all conductive patch elements located on the first substrate.
24. The antenna assembly of claim 1 , wherein the number of the plurality of pairs of apertures located on the first layer of the second substrate equals a number of all pairs of apertures located on the first layer of the second substrate.
25. The antenna assembly of claim 1 , wherein the number of the plurality of third substrate conductive patch elements located on the third substrate equals a number of all conductive patch elements located on the third substrate.
26. The antenna assembly of claim 1 , wherein each one of the plurality of third substrate conductive patch elements located on the third substrate is concentric with a respective one of the plurality of first substrate conductive patch elements located on the first substrate.
27. The antenna assembly of claim 1 , wherein each one of the plurality of third substrate conductive patch elements located on the third substrate is coincident with a projection of a respective one of the plurality of first substrate conductive patch elements located on the first substrate.
28. The antenna assembly of claim 1 , wherein each one of the plurality of first substrate conductive patch elements located on the first substrate is larger in projected area than a respective one of the plurality of third substrate conductive patch elements located on the third substrate.
29. The antenna assembly of claim 1 , wherein each one of the plurality of first substrate conductive patch elements located on the first substrate and each one of the plurality of third substrate conductive patch elements located on the third substrate is circular.
30. The antenna assembly of claim 1 , wherein the third substrate is formed from a dielectric film material.
31. The antenna assembly of claim 1 , wherein the first substrate is formed from a dielectric film material.
32. The antenna assembly of claim 1 , wherein the third substrate is formed from a dielectric film material and the first substrate is formed from a dielectric film material.
33. The antenna assembly of claim 1 , wherein the third substrate is formed from a dielectric film material and the first substrate is formed from a printed circuit board.
34. The antenna assembly of claim 1 , wherein the first aperture of each pair of the plurality of pairs of apertures excites a respective stacked resonant radiating antenna element formed amongst each respective one of the plurality of first substrate conductive patch elements, each respective one of the plurality of third substrate conductive patch elements and the conductive ground plane in an electromagnetic mode corresponding to a first 45-degree far-field pattern, and wherein the second aperture of each pair of the plurality of pairs of apertures excites said respective stacked resonant radiating antenna element in an electromagnetic mode corresponding to a second 45-degree far-field pattern that is orthogonal to the first 45-degree far-field pattern.
35. The antenna assembly of claim 1 , wherein the first spacer has a number of first spacer openings equal to one quarter or one half of the number of the plurality of third substrate conductive patch elements.
36. The antenna assembly of claim 29 , wherein each one of the first spacer openings is circular and the first spacer has a number of first spacer openings equal to the number of the plurality of third substrate conductive patch elements.
37. The antenna assembly of claim 1 , wherein the first spacer is identical to the second spacer.
38. The antenna assembly of claim 1 , wherein a plurality of respective stacked resonant radiating antenna elements formed amongst each respective one of the plurality of first substrate conductive patch elements, each respective one of the plurality of third substrate conductive patch elements and the conductive ground plane, a plurality of respective first apertures from each respective pair of the plurality of pairs of apertures and the first transmission line feed network form a first phased array antenna.
39. The antenna assembly of claim 38 , wherein the plurality of respective stacked resonant radiating antenna elements, a plurality of respective second apertures from each respective pair of the plurality of pairs of apertures and the second transmission line feed network form a second phased array antenna.
40. The antenna assembly of claim 1 , wherein each of the first aperture and the second aperture of each respective pair of the plurality of pairs of apertures comprises an aperture body.