Antenna array apparatus with conformal mounting structure

• US 6,407,711 B1
• Filed: 04/24/2001
• Issued: 06/18/2002
• Est. Priority Date: 04/24/2001
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Composite Concepts Company (Northrop Grumman Corporation), Scientific & Efficient Technologies, Ltd.
• Inventors: Zimmer, William, Sinclair, Rodney, Bonebright, Mark, McNaul, Bill, Rerecich, Tony, Weatherington, Jon Duff, Wittmond, John
• Primary Examiner(s): Ho, Tan
• Application Number:
  US09/841,829
• Time in Patent Office: 420 Days
• Field of Search: 343/705, 343/708, 343/700.MS, 343/853, 343/878, 343/906, 343/872
• US Class Current: 343/705
• CPC Class Codes: H01Q 1/286 substantially flush mounted with the skin of the craft
• CPC Class Codes: H01Q 21/205 providing an omnidirectional coverage turnstile aerials H01Q21/26

Abstract

A carrier structure apparatus for mounting conformal antenna elements to a non-planar mounting surface as part of an antenna array of an airborne vehicle or ground-based system also comprising a seeker section, fairing and guidance processing system. The carrier structure is a rigid and conductive apparatus that is made to conform to the geometric configuration of both the antenna element as well as the mounting surface. The conformal antenna is rigidly mounted to the carrier structure, which is in turn removably affixed to the non-planar mounting surface. With the carrier structure, each antenna element of the array may be individually tested and replaced prior to and after installation in array.

Claims

1. An antenna apparatus having a signal distribution network, the apparatus comprising:

a. a mounting structure having an exterior skin and a recessed channel;

b. a plurality of conformal antenna units detachably affixed to the mounting structure at the recessed channel;

each conformal antenna unit comprising;

(1) an antenna element having a top surface and an opposing base;

(2) an antenna electrical connecting means in electrical communication with the antenna element;

the antenna electrical connecting means being removably attachable with the signal distribution network;

(3) a carrier structure, of minimal thickness, comprising an upper surface and lower surface;

the upper surface of the carrier structure being permanently affixed to the base of the antenna element, and the lower surface being detachably affixed to the recessed channel of the mounting structure;

c. a fairing for enclosing the recessed channel;

the fairing being substantially flush with the exterior skin of the mounting structure; and

d. dielectric potting of low loss tangent for encapsulating the conformal antenna units within the fairing;

whereby the top surface of each antenna element substantially conforms to the exterior skin of the mounting structure.

2. The antenna apparatus of claim 1, wherein the upper surface of the carrier structure has a matching section that is of substantially uniform curvature and continuous between the base of the antenna element and the exterior skin of the mounting structure.

3. The antenna apparatus of claim 2, wherein the antenna element is a broadband, directional antenna characterizable by a main beam and a bandwidth.

4. The antenna apparatus of claim 3, wherein the signal distribution network is further connected to a multi-channel receiver system.

5. The antenna apparatus of claim 4, wherein the mounting structure is substantially conical and characterized by a principal axis;

the recessed channel circumscribing the conical mounting structure in a plane transverse to the principal axis of the mounting structure;

the recessed channel having a depth minimally sufficient to accommodate the conformal antenna unit.

6. The antenna apparatus of claim 5, wherein the conformal antenna units are mounted around the circumference of the recessed channel of the mounting structure with substantially uniform unit-to-unit separation.

7. The antenna apparatus of claim 6, wherein the plurality of carrier structures are brought into substantial conformity with the recessed channel of the mounting structure in the direction of the main beam of the antenna elements such that a gap between the carrier structures and the mounting structure is less than two mils.

8. The antenna apparatus of claim 7, wherein the dielectric potting is a syntactic material.

9. The antenna apparatus of claim 8, wherein the antenna apparatus further comprises a plurality of calibration units, each calibration unit being removably affixed to two adjacent carrier structures such that the calibration unit is symmetrically disposed between two adjacent antenna elements.

10. A conformal antenna apparatus having a signal distribution network, the antenna apparatus comprising:

a. a mounting structure having a substantially non-planar surface;

b. a plurality of conformal antenna elements, each antenna element having a top surface and a bottom surface;

the antenna element having a characteristic main beam;

c. a plurality of carrier structures of a conductive material;

each carrier structure having an upper surface and a lower surface, the upper surface of the carrier structure having a forward portion and a rear portion;

the lower surface of each carrier structure being substantially conformal to the mounting structure;

d. bonding means for permanently affixing the bottom surface of the antenna elements to the rear portion of the carrier structures;

e. fastening means for detachably anchoring the carrier structures to the mounting structure;

f. electrical connecting means for bringing the antenna elements in detachable electrical communication with the signal distribution network;

g. a fairing structure attached to the mounting structure for enclosing the antenna elements; and

h. a dielectric potting for encapsulating the antenna elements within the fairing structure after being affixed to the mounting structure.

11. The antenna apparatus of claim 10, wherein the signal distribution network is further connected to a multi-channel receiver system characterized by a bandwidth.

12. The antenna apparatus of claim 11, wherein the antenna elements are uniformly mounted in one or more ring-like configurations in conformity with the mounting structure.

13. The antenna apparatus of claim 12, wherein the rear portion of the carrier structure is substantially planar at the junction where the antenna element is permanently affixed to the carrier structure.

14. The antenna apparatus of claim 13, wherein the forward portion of the carrier structure has a substantially uniform radius, in a coronal plane of an airborne vehicle, between the mounting structure and the bottom surface of the antenna element when detachably anchored to the carrier structure;

the uniform radius being substantially equal to or greater than a quarter wavelength of a frequency of the bandwidth associated with the receiver system that is lowest.

15. The antenna apparatus of claim 14, wherein the upper surface of the carrier structure in the direction of the main beam is in substantial conformity with the mounting structure, thereby maintaining continuous and uniform electrical contact between the carrier structure and the mounting structure.

16. The antenna apparatus of claim 15, wherein the fastening means is comprised of a plurality of threaded bolts seated in a first set of holes in the carrier structure, the bolts engaging a second set of holes in the mounting structure;

the second set of holes being threaded and axially biased with respect to the corresponding first set of holes toward the direction of the main beam of the antenna element;

whereby the carrier structure is made to apply pressure to the mounting structure in a direction transverse to the threaded bolts.

17. The antenna apparatus of claim 12, wherein the apparatus further includes a plurality of calibration elements;

each calibration element being affixed equidistantly between two adjacent antenna elements.

18. The antenna apparatus of claim 17, wherein each calibration element is removably mounted directly to two adjacent carrier structures.

19. The antenna apparatus of claim 10, wherein the dielectric potting is a syntactic material.

20. A carrier structure for affixing an antenna element to a non-planar mounting structure;

the carrier structure being substantially thin, rigid and electrically conductive;

the carrier structure comprising;

a. a leading edge substantially flush with the mounting structure at the conjunction of the carrier structure and mounting structure;

b. an upper surface comprising;

(1) a rear portion for directly and inseparably affixing an antenna element;

the rear portion of the upper surface substantially conformal to the antenna element;

(2) a forward portion having a substantially smooth surface between the leading edge of the carrier structure and the antenna element;

c. a lower surface substantially conformal to the non-planar mounting structure; and

d. mounting means for removably attaching the carrier structure to the mounting structure.

21. The carrier structure of claim 20, wherein the forward portion is a surface of curvature having a substantially uniform radius between the antenna element and the leading edge of the carrier structure;

the uniform radius being substantially equal to a quarter of a wavelength of a lowest frequency of interest associated with a bandwidth of interest.

22. The carrier structure of claim 21, wherein the lower surface subtends an angular subsection of a substantially conical surface conformal to the mounting structure.

23. The carrier structure of claim 22, wherein the rear portion is substantially planar;

the carrier structure being directly and inseparably affixed to the antenna element.

24. The carrier structure of claim 23, wherein the upper surface further includes one or more planar facets such that each facet, together with a planar facet of an adjacent carrier structure, forms a continuous planar surface for mounting a calibration unit.