Continuous transverse stub element devices and methods of making same

• US 5,266,961 A
• Filed: 08/29/1991
• Issued: 11/30/1993
• Est. Priority Date: 08/29/1991
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Milroy, William W.
• Primary Examiner(s): Bovernick, Rodney B.
• Assistant Examiner(s): Wise, Robert E.
• Application Number:
  US07/751,282
• Time in Patent Office: 824 Days
• Field of Search: 343/772, 343/767, 343/770, 343/785, 343/786, 343/771, 333/237, 333/239, 333/248
• US Class Current: 343/772
• 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 13/28 comprising elements constituting electric discontinuities and spaced in direction of wave propagation, e.g. dielectric elements or conductive elements forming artificial dielectric

Abstract

A dielectric material is formed into a structure having two parallel broad surfaces with one or more raised integral portions extending transversely across at least one of the broad surfaces. The exterior is uniformly conductively coated resulting in a parallel plate waveguide having a continuous transverse stub element disposed adjacent one plate thereof. Purely reactive elements are formed by leaving the conductive coating on the terminus of the stub element, or by narrowing the terminus of the stub element. Radiating elements are formed when stub elements of moderate height are opened to free space. Radiating, coupling and/or reactive continuous transverse stub elements may be combined in a common parallel plate structure in order to form a variety of microwave, millimeter wave and quasi-optical components including integrated filters, couplers and antenna arrays. Fabrication of the dielectrically-loaded continuous transverse stub element can be efficiently accomplished by machining, extruding or molding the dielectric structure, followed by uniform conductive plating in order to form the parallel plate transmission line. In the case of antenna applications, machining or grinding is performed on the stub terminus to expose the dielectric material at the end of the stub element.

Claims

1. Antenna means comprising:

a dielectric element comprising a first portion and a second portion that extends generally transverse to the first portion that forms a transverse stub that protrudes from a first surface of the first portion;

a first conductive element disposed coextensive with the dielectric element along a second surface of the first portion; and

a second conductive element disposed along the first surface of the dielectric element and disposed along transversely extending edgewalls formed by the second portion of the dielectric element.

2. The antenna means of claim 1 wherein the second conductive element extends across an end of the dielectric element, thus enclosing it to form an shorted waveguide.

3. The antenna means of claim 1 wherein the second portion of the dielectric element extends substantially along the length of the dielectric element.

4. The antenna means of claim 1 wherein the length and width of the second portion are substantially the same, thus forming a coupler.

5. The antenna means of claim 1 wherein the dielectric element further comprises:

a third portion having a length, width, and cross section that are substantially the same as the first portion that is coupled to the end of the second portion, and wherein the second conductive coating extends along a first surface of the third portion that is proximal to the first portion; and

a third conductive element disposed along a second surface of the third portion of the dielectric element that is distal from the first conductive predetermined element, thus forming a coupler.

6. The antenna means of claim 1 wherein the dielectric element comprises air and which further comprises a slow wave structure disposed along an inner surface of the first conductive coating adjacent the second portion of the transverse stub.

7. The antenna means of claim 1 wherein the dielectric element comprises a plurality of dielectric layers having different dielectric coefficients.

8. The antenna means of claim 1 wherein the dielectric element comprises a fourth portion disposed on the same side of the first portion as the second portion that extends generally transverse to the first portion and that is oriented orthogonal to the second portion, which fourth portion forms a second transverse stub that is orthogonally oriented with respect to the transverse stub.

9. The antenna means of claim 8 which further comprises a plurality of line sources individually coupled to selected adjacent edges of the dielectric element.

10. The antenna means of claim 1 which further comprises first and second terminating surfaces disposed along opposite lateral edges of the first and second portions of the dielectric member, thus forming a finite width stub element.

11. The antenna means of claim 10 wherein the first and second terminating surfaces comprise conductive surfaces.

12. The antenna means of claim 10 wherein the first and second terminating surfaces comprise nonconductive surfaces.

13. The antenna means of claim 10 wherein the first and second terminating surfaces comprise absorptive surfaces.

14. The antenna means of claim 1 wherein the second portion of the dielectric element has a tapered cross section.

15. The antenna means of claim 1 wherein the second portion of the dielectric element has a stepped configuration.

16. The antenna means of claim 15 wherein the first portion of the dielectric element has a stepped configuration.

17. The antenna means of claim 1 wherein the first portion of the dielectric element has a stepped configuration.

18. The antenna means of claim 1 wherein the second portion of the dielectric element has a circular shape forming a circular transverse stub.

19. The antenna means of claim 1 wherein the dielectric element comprises a plurality of second portions that protrude transversely from the first surface of the first portion and that are separated from each other by a predetermined distance.

20. The antenna means of claim 19 wherein each of the respective transverse stubs have distinct widths that become progressively smaller relative to their positions across the antenna means.

21. The antenna means of claim 19 which further comprises a conductive element disposed between adjacent transverse stubs, which form a plurality of transverse cavities.

22. The antenna means of claim 19 wherein the dielectric element further comprises an additional plurality of transversely extending portions disposed between adjacent ones of the plurality of second portions that are individually rotated with respect to the second portions.

23. The antenna means of claim 19 wherein the dielectric element has a contoured cross section adapted to conform to a predetermined nonplanar shape, and wherein the plurality of second portions individually extend along a plurality of radial lines determined by the shape of the contour.

24. The antenna means of claim 19 wherein each of the plurality of second portions has substantially the same height.

25. The antenna means of claim 19 wherein selected ones of the plurality of second portions have different heights relative to the remainder of the second portions.

26. The antenna means of claim 19 wherein the dielectric element has a semicircular shape.

27. An antenna array comprising:

a planar sheet of dielectric material having two generally parallel broad surfaces separated by a predetermined distance and having a plurality of elongated, raised, relatively thin, rectangular dielectric members formed along a broad surface of the sheet of dielectric material that extend across one dimension of the broad surface and that extend away from the broad surface, and wherein the plurality of thin rectangular dielectric members are spaced apart from each other by a predetermined distance; and

a conductive material disposed on the broad surfaces of the sheet of dielectric material and on transversely extending edgewalls formed by the plurality of thin rectangular dielectric members so as to define a parallel plate waveguide having a plurality of continuous transverse stubs disposed on one plate thereof, and wherein distal ends of the plurality of thin rectangular dielectric members are free of the conductive material so as to define a plurality of radiating elements, and wherein an edge of the sheet of dielectric material is free of conductive coating so as to define a feed for the antenna array.

28. The antenna array of claim 27 wherein each of the respective dielectric members have distinct widths that become progressively smaller relative to their position in the antenna array.

29. The antenna array of claim 27 wherein the conductive material is disposed over the distal ends of the thin rectangular dielectric members to define a short circuited radiating elements, the apparatus thus comprising a short circuit stub antenna array.

30. The antenna array of claim 27 further comprising:

a second planar rectangular sheet of dielectric material having two generally parallel broad surfaces separated by a predetermined distance and wherein one of the surfaces is integrally connected to the plurality of elongated, raised, relatively thin, rectangular dielectric members; and

wherein the conductive material is disposed on the other of the surfaces of the second sheets of dielectric material to define a pair of parallel plate waveguides having a plurality of continuous transverse coupling stubs coupled therebetween.

31. A method of making a continuous transverse stub antenna element which comprises the following steps:

processing a sheet of dielectric material to form an integral dielectric member having two generally parallel broad surfaces and at least one elongated raised relatively thin rectangular dielectric portion extending transversely across one of the broad surfaces;

metalizing the exterior surfaces of the dielectric member to define a parallel plate waveguide having at least one continuous transverse stub disposed on one plate thereof; and

removing plating from predetermined surfaces of the exterior of the parallel plate waveguide to permit coupling of energy into and out of the antenna element.

32. The method of making a continuous transverse stub antenna element of claim 31 wherein the step of processing a sheet of dielectric material comprises the step of:

machining a sheet of dielectric material to form a dielectric member having two generally parallel broad surfaces and at least one elongated raised relatively thin rectangular dielectric portion extending transversely across one of the broad surfaces.

33. The method of making a continuous transverse stub antenna element of claim 31 wherein the step of processing a sheet of dielectric material comprises the step of:

extruding a sheet of dielectric material in the form of a dielectric member having two generally parallel broad surfaces and at least one elongated raised relatively thin rectangular dielectric portion extending transversely across one of the broad surfaces.

34. The method of making a continuous transverse stub element of claim 31 wherein the step of processing a sheet of dielectric material comprises the step of:

molding a sheet of dielectric material to form a dielectric member having two generally parallel broad surfaces and at least one elongated raised relatively thin rectangular dielectric portion extending transversely across one of the broad surfaces.