Continuous transverse stub element devices for flat plate antenna arrays

• US 5,483,248 A
• Filed: 08/10/1993
• Issued: 01/09/1996
• Est. Priority Date: 08/10/1993
• 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): Hajec, Donald T.
• Assistant Examiner(s): Ho, Tan
• Application Number:
  US08/104,466
• Time in Patent Office: 882 Days
• Field of Search: 343/767, 343/772, 343/785, 343/786, 333/237, 333/238, 333/248
• 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 13/28 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. An antenna array employing continuous transverse stubs as radiating elements, said antenna array comprising:

a planar rectangular sheet of dielectric material having two parallel broad surfaces separated by a predetermined distance;

a plurality of elongated raised relatively thin rectangular dielectric members integral with said sheet of dielectric material and extending transversely across one of the broad surfaces of said sheet of dielectric material, said plurality of thin rectangular dielectric members being evenly spaced from each other and regularly disposed along said sheet of dielectric material;

a thin conducting layer disposed on the exterior of said sheet of dielectric material and on the exterior of said plurality of thin rectangular dielectric members to define a parallel plate waveguide having a plurality of continuous transverse stubs disposed on one plate thereof, the surfaces of said plurality of thin rectangular dielectric members distal from said sheet of dielectric material being free from said conductive coating so as to define a plurality of radiating elements, one narrow side of said sheet of dielectric material being free from said conductive coating so as to define a feed for the antenna array; and

a plurality of non-radiating matching elements disposed between the continuous transverse stubs, wherein the non-radiating matching elements comprise depressions in the parallel-plate waveguide.

2. The antenna array of claim 1 wherein each of said transverse stubs is a longitudinal incidence stub element.

3. The antenna array of claim 1 with a parameter variation of said transverse stubs in a transverse direction.

4. The antenna array of claim 1 wherein each of said transverse stubs is a multi-stage stub element.

5. The antenna array of claim 1 wherein the transverse elements are paired elements to comprise a matched couplet.

6. The antenna array of claim 1 wherein radiating and non-radiating transverse stubs are pairs comprising a matched couplet.

7. The antenna array of claim 1 wherein said array provides circular polarization.

8. The antenna array of claim 1 wherein the array is a dual polarization antenna array.

9. The antenna array of claim 1 wherein the array is a squint-beam antenna array.

10. The antenna array of claim 1 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thin conducting sheet.

11. The antenna array of claim 1 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thick conducting plate having a thickness value substantially the same as height of the stubs.

12. The antenna array of claim 1 wherein the conductive coating comprises a solid homogeneous conductor.

13. The antenna array of claim 1 wherein the conductive coating comprises a hollow or inhomogeneously-filled cavity surrounded by a thin conducting layers.

14. The antenna array of claim 1 wherein the conductive coating is formed in the shape of relatively long strips.

15. The antenna array of claim 1 wherein the conductive coating is formed in the shape of squares.

16. The antenna array of claim 1 wherein the non-radiating matching elements comprise extensions in the parallel-plate waveguide.

17. The antenna array of claim 1 which further comprises a superstrate disposed above the plurality of continuous transverse stubs.

18. The antenna array of claim 17 wherein the superstrate is comprised of at least one dielectric layer covering the antenna array.

19. The antenna array of claim 17 wherein the dielectric layer is formed from the group of dielectric materials including rexolite, polyethylene, stycast, lexan, air, and low-density foam.

20. An antenna array employing continuous transverse stubs as radiating elements, said antenna array comprising:

a planar rectangular sheet of dielectric material having two parallel broad surfaces separated by a predetermined distance;

a plurality of elongated raised relatively thin rectangular dielectric members integral with said sheet of dielectric material and extending transversely across one of the broad surfaces of said sheet of dielectric material, said plurality of thin rectangular dielectric members being evenly spaced from each other and regularly disposed along said sheet of dielectric material;

a thick conducting layer disposed on the exterior of said sheet of dielectric material and on the exterior of said plurality of thin rectangular dielectric members to define a parallel plate waveguide having a plurality of continuous transverse stubs disposed on one plate thereof, the surfaces of said plurality of thin rectangular dielectric members distal from said sheet of dielectric material being free from said conductive coating so as to define a plurality of radiating elements, one narrow side of said sheet of dielectric material being free from said conductive coating so as to define a feed for the antenna array; and

a plurality of non-radiating matching elements disposed between the continuous transverse stubs, wherein the non-radiating matching elements comprise complementary depressions in an upper conductor-region.

21. The antenna array of claim 20 wherein each of said transverse stubs is a longitudinal incidence stub element.

22. The antenna array of claim 20 with a parameter variation of said transverse stubs in a transverse direction.

23. The antenna array of claim 20 wherein each of said transverse stubs is a multi-stage element.

24. The antenna array of claim 20 wherein said transverse elements are paired elements to comprise a matched couplet.

25. The antenna array of claim 20 wherein radiating and non-radiating transverse stubs are pairs comprising a matched couplet.

26. The antenna array of claim 20 wherein said array provides circular polarization.

27. The antenna array of claim 20 wherein the array is a dual polarization antenna array.

28. The antenna array of claim 20 wherein the array is a squint-beam antenna array.

29. The antenna array of claim 20 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprising a thin conductive sheet.

30. The antenna array of claim 20 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thick conducting plate having a thickness value substantially the same as height of the stubs.

31. The antenna array of claim 20 wherein the conductive coating comprises a solid homogeneous conductor.

32. The antenna array of claim 20 wherein the conductive coating comprises a hollow or inhomogeneously-filled cavity surrounded by thin conducting layers.

33. The antenna array of claim 20 wherein the conductive coating is formed in the shape of relatively long strips.

34. The antenna array of claim 20 wherein the conductive coating is formed in the shape of squares.

35. The antenna array of claim 20 wherein the non-radiating matching elements comprise extensions in the parallel-plate waveguide.

36. The antenna array of claim 20 which further comprises a superstrate disposed above the plurality of continuous transverse stubs.

37. The antenna array of claim 36 wherein the superstrate is comprised of at least one dielectric layer covering the antenna array.

38. The antenna array of claim 37 wherein the dielectric layer is formed from the group of dielectric materials including rexolite, polyethylene, stycast, lexan, air, arid low-density foam.

39. An antenna array employing continuous transverse stubs as radiating elements, said antenna array comprising:

a planar rectangular sheet of dielectric material having two parallel broad surfaces separated by a predetermined distance;

a plurality of elongated raised relatively thin rectangular dielectric members integral with said sheet of dielectric material and extending transversely across one of the broad surfaces of said sheet of dielectric material, said plurality of thin rectangular dielectric members being evenly spaced from each other and regularly disposed along said sheet of dielectric material;

a thick conducting layer disposed on the exterior of said sheet of dielectric material and on the exterior of said plurality of thin rectangular dielectric members to define a parallel plate waveguide having a plurality of continuous transverse stubs disposed on one plate thereof, the surfaces of said plurality of thin rectangular dielectric members distal from said sheet of dielectric material being free from said conductive coating so as to define a plurality of radiating elements, one narrow side of said sheet of dielectric material being free from said conductive coating so as to define a feed for the antenna array; and

a plurality of non-radiating matching elements disposed between the continuous transverse stubs, wherein the non-radiating matching elements comprise complementary extensions in an upper conductor region.

40. The antenna array of claim 39 wherein each of said transverse stubs is a longitudinal incidence stub element.

41. The antenna array of claim 39 with a parameter variation of said transverse stubs in a transverse direction.

42. The antenna array of claim 39 wherein each of said transverse stubs is a multi-stage stub element.

43. The antenna array of claim 39 wherein said transverse elements are paired elements to comprise a matched couplet.

44. The antenna array of claim 39 wherein radiating and non-radiating transverse stubs are pairs comprising a matched couplet.

45. The antenna array of claim 39 wherein said array provides circular polarization.

46. The antenna array of claim 39 wherein the array is a dual polarization antenna array.

47. The antenna array of claim 39 wherein the array is a squint-beam antenna array.

48. The antenna array of claim 39 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thin conducting sheet.

49. The antenna array of claim 39 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thick conducting plate having a thickness value substantially the same as height of the stubs.

50. The antenna array of claim 39 wherein the conductive coating comprises a solid homogeneous conductor.

51. The antenna array of claim 39 wherein the conductive coating comprises a hollow or inhomogeneously-filled cavity surrounded by thin conducting layers.

52. The antenna array of claim 39 wherein the conductive coating is formed in the shape of relatively long strips.

53. The antenna array of claim 39 wherein the conductive coating is formed in the shape of squares.

54. The antenna array of claim 39 wherein the non-radiating matching elements comprise extensions in the parallel-plate waveguide.

55. The antenna array of claim 39 which further comprises a superstrate disposed above the plurality of continuous transverse stubs.

56. The antenna array of claim 55 wherein the superstrate is comprised of at least one dielectric layer covering the antenna array.

57. The antenna array of claim 56 wherein the dielectric layer is formed from the group of dielectric materials including rexolite, polyethylene, stycast, lexan, air, and low-density foam.

58. An antenna array employing continuous transverse stubs as radiating elements, said antenna array comprising:

a planar rectangular sheet of dielectric material having two parallel broad surfaces separated by a predetermined distance;

a plurality of elongated raised relatively thin rectangular dielectric members integral with said sheet of dielectric material and extending transversely across one of the broad surfaces of said sheet of dielectric material, said plurality of thin rectangular dielectric members being evenly spaced from said other and regularly disposed along said sheet of dielectric material;

a conductive coating disposed on he exterior of said sheet of dielectric material and on the exterior of said plurality of thin rectangular dielectric members to define a parallel plate waveguide having a plurality of continuous transverse stubs disposed on one plate thereof, the surfaces of said plurality of thin rectangular dielectric members distal from said sheet of dielectric material being free from said conductive coating so as to define a plurality of radiating elements, one narrow said of said sheet of dielectric material being free from said conductive coating so as to define a feed for the antenna array; and

a plurality of non-radiating matching elements disposed between the continuous transverse stubs, wherein the non-radiating matching elements comprise offset troughs that are continuous in the transverse dimension.

59. The antenna array of claim 58 wherein each of said transverse stubs is a longitudinal incidence stub element.

60. The antenna array of claim 58 with a parameter variation of said transverse stubs in a transverse direction.

61. The antenna array of claim 58 wherein each of said transverse stubs is a multi-stage stub element.

62. The antenna array of claim 58 wherein said transverse elements are paired to comprise a matched couplet.

63. The antenna array of claim 58 wherein radiating and non-radiating transverse stubs are pairs comprising a matched couplet.

64. The antenna array of claim 58 wherein said array provides circular polarization.

65. The antenna array of claim 58 wherein the array is a dual polarization antenna array.

66. The antenna array of claim 58 wherein the array is a squint-beam antenna array.

67. The antenna array of claim 58 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thin conducting sheet.

68. The antenna array of claim 58 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thick conducting late having a thickness value substantially the same as height of the stubs.

69. The antenna array of claim 58 wherein the conductive coating comprises a solid homogeneous conductor.

70. The antenna array of claim 58 wherein the conductive coating comprises a hollow or inhomogeneously-filled cavity surrounded by thin conducting layers.

71. The antenna array of claim 58 wherein the conductive coating is formed in the shape of relatively long strips.

72. The antenna array of claim 58 wherein the conductive coating is formed in he shape of squares.

73. The antenna array of claim 58 wherein the non-radiating matching elements comprise extensions in the parallel-plate waveguide.

74. The antenna array of claim 58 which further comprises a superstrate dispose above the plurality of continuous transverse stubs.

75. The antenna array of claim 74 wherein the superstrate is comprised of at least one dielectric layer covering the antenna array.

76. The antenna array of claim 75 wherein the dielectric layer is formed from the group of dielectric materials including rexolite, polyethylene, stycast, lexan, air, and low-density foam.

77. An antenna array employing continuous transverse stubs as radiating elements, said antenna array comprising:

a planar rectangular sheet of dielectric material having two parallel broad surfaces separated by a predetermined distance;

a plurality of elongated raised relatively thin rectangular dielectric members integral with said sheet of dielectric material and extending transversely across one of the broad surfaces of said sheet of dielectric material, said plurality of thin rectangular dielectric members being evenly spaced from each other and regularly disposed along said sheet of dielectric material;

a conductive coating disposed on the exterior of said sheet of dielectric material and on the exterior of said plurality of thin rectangular dielectric members to define a parallel plate waveguide having a plurality of continuous transverse stubs disposed on one plate thereof, the surfaces of said plurality of thin rectangular dielectric members distal from said sheet of dielectric material being free from said conductive coating so as to define a plurality of radiating elements, one narrow side of said sheet of dielectric material being free from said conductive coating so as to define a feed for the antenna array; and

a plurality of non-radiating matching element disposed between the continuous transverse stubs, wherein the non-radiating matching elements comprise offset ridges that are continuous in the transverse dimension.

78. The antenna array of claim 77 wherein each of said transverse stubs is a longitudinal incidence stub element.

79. The antenna array of claim 77 with a parameter variation of said transverse stubs in a transverse direction.

80. The antenna array of claim 77 wherein each of said transverse stubs is a multi-stage stub element.

81. The antenna array of claim 77 wherein said transverse elements are paired elements to comprise a matched couplet.

82. The antenna array of claim 77 wherein radiating and non-radiating transverse stubs are pairs comprising a matched couplet.

83. The antenna array of claim 77 wherein said array provides circular polarization.

84. The antenna array of claim 77 wherein the array is a dual polarization antenna array.

85. The antenna array of claim 77 wherein the array is a squint-beam antenna array.

86. The antenna array of claim 77 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thin conducting sheet.

87. The antenna array of claim 77 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thick conducting plate having a thickness value substantially the same as height of the stubs.

88. The antenna array of claim 77 wherein the conductive coating comprises a solid homogeneous conductor.

89. The antenna array of claim 77 wherein the conductive coating comprises a hollow or inhomogeneously-filled cavity surrounded by thin conducting layers.

90. The antenna array of claim 77 wherein the conductive coating is formed in the shape of relatively long strips.

91. The antenna array of claim 77 wherein the conductive coating is formed in the shape of squares.

92. The antenna array of claim 77 wherein the non-radiating matching elements comprise extensions in the parallel-plate waveguide.

93. The antenna array of claim 77 which further comprises a superstrate disposed above the plurality of continuous transverse stubs.

94. The antenna array of claim 93 wherein the superstrate is comprised of at least one dielectric layer covering the antenna array.

95. The antenna array of claim 94 wherein the dielectric layer is formed from the group of dielectric materials including rexolite, polyethylene, stycast, lexan, air, and low-density foam.

96. An antenna array employing continuous transverse stubs as radiating elements, said antenna array comprising:

a planar rectangular sheet of dielectric material having two parallel broad surfaces separated by a predetermined distance;

a plurality of elongated raised relatively thin rectangular dielectric members integral with said sheet of dielectric material and extending transversely across one of the broad surfaces of said sheet of dielectric material, said plurality of thin rectangular dielectric members being evenly spaced from each other and regularly disposed along said sheet of dielectric material;

a conductive coating disposed on the exterior of said sheet of dielectric material and on the exterior of said plurality of thin rectangular dielectric members to define a parallel plate waveguide having a plurality of continuous transverse stubs disposed on one plate thereof, the surfaces of said plurality of thin rectangular dielectric members distal from said sheet of dielectric material being free from said conductive coating so as to define a plurality of radiating elements, one narrow side of said sheet of dielectric material being free form said conductive coating so as to define a feed for the antenna array; and

a plurality of non-radiating matching element disposed between the continuous transverse stubs, wherein the non-radiating matching elements comprise troughs that form discrete offset crosses in an inter-stub region.

97. The antenna array of claim 96 wherein each of said transverse stubs is a longitudinal incidence stub element.

98. The antenna array of claim 96 with a parameter variation of said transverse stubs in a transverse direction.

99. The antenna array of claim 96 wherein each of said transverse stubs is a multi-stage stub element.

100. The antenna array of claim 96 wherein said transverse elements are paired elements to comprise a matched couplet.

101. The antenna array of claim 96 wherein radiating and non-radiating transverse stubs are pairs comprising a matched couplet.

102. The antenna array of claim 96 wherein said array provides circular polarization.

103. The antenna array of claim 96 wherein the array is a dual polarization antenna array.

104. The antenna array of claim 96 wherein the array is a squint-beam antenna array.

105. The antenna array of claim 96 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thin conducting sheet.

106. The antenna array of claim 96 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thick conducting plate having a thickness value substantially the same as height of the stubs.

107. The antenna array of claim 96 wherein the conductive coating comprises a solid homogeneous conductor.

108. The antenna array of claim 96 wherein the conductive coating comprises a hollow or inhomogeneously-filled cavity surrounded by thin conducting layers.

109. The antenna array of claim 96 wherein the conductive coating is formed in the shape of relatively long strips.

110. The antenna array of claim 96 wherein the conductive coating is formed in he shape of squares.

111. The antenna array of claim 96 wherein the non-radiating matching elements comprise extensions in the parallel-plate waveguide.

112. The antenna array of claim 96 which further comprises a superstrate disposed above the plurality of continuous transverse stubs.

113. The antenna array of claim 112 wherein the superstrate is comprised of at lest one dielectric layer covering he antenna array.

114. The antenna array of claim 113 wherein the dielectric layer is formed from the group of dielectric materials including rexolite, polyethylene, stycast, lexan, air, and low-density foam.

115. The antenna array employing continuous transverse stubs as radiating elements, said antenna array comprising:

a planar rectangular sheet of dielectric material having two parallel broad surfaces separated by a predetermined distance;

a plurality of elongated raised relatively thin rectangular dielectric members integral with said sheet of dielectric material and extending transversely across one of the broad surfaces of said sheet of dielectric material, said plurality of thin rectangular dielectric members being evenly spaced from each other and regularly disposed along said sheet of dielectric material;

a conductive coating disposed on the exterior of said sheet of dielectric material and on the exterior of said plurality of thin rectangular dielectric members to define a parallel plate waveguide having a plurality of continuous transverse stubs disposed on one plate thereof, the surfaces of said plurality of thin rectangular dielectric members distal from said sheet of dielectric material being free from said conductive coating so as to define a plurality of radiating elements, one narrow side of said sheet of dielectric material being free from said conductive coating so as to define a feed for the antenna array; and

a plurality of non-radiating matching elements disposed between the continuous transverse stubs, wherein the non-radiating matching elements comprise ridges that form discrete offset crosses in an inter-stub region.

116. The antenna array of claim 115 wherein each of said transverse stubs is a longitudinal incidence stub element.

117. The antenna array of claim 115 with a parameter variation of said transverse stubs in a transverse direction.

118. The antenna array of claim 115 wherein each of said transverse stubs is a multi-stage stub element.

119. The antenna array of claim 115 wherein said transverse elements are paired elements to comprise a matched couplet.

120. The antenna array of claim 115 wherein radiating and non-radiating transverse stubs are pairs comprising a matched couplet.

121. The antenna array of claim 115 wherein said array provides circular polarization.

122. The antenna array of claim 115 wherein the array is a dual polarization antenna array.

123. The antenna array of claim 115 wherein the array is a squint-beam antenna array.

124. The antenna array of claim 115 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thin conducting sheet.

125. The antenna array of claim 115 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thick conducting plate having a thickness value substantially the same as height of the stubs.

126. The antenna array of claim 115 wherein the conductive coating comprises a solid homogeneous conductor.

127. The antenna array of claim 115 wherein the conductive coating comprises a hollow or inhomogeneously-filled cavity surrounded by thin conducting layers.

128. The antenna array of claim 115 wherein the conductive coating is formed in the shape of relatively long strips.

129. The antenna array of claim 115 wherein the conductive coating is formed in the shape of squares.

130. The antenna array of claim 115 wherein the non-radiating matching elements comprise extensions in the parallel-plate waveguide.

131. The antenna array of claim 115 which further comprises a superstrate disposed above the plurality of continuous transverse stubs.

132. The antenna array of claim 131 wherein the superstrate is comprises of at least one dielectric layer covering the antenna array.

133. The antenna array of claim 132 wherein the dielectric layer is formed from the group of dielectric materials including rexolite, polyethylene, stycast, lexan, air, and low-density foam.

134. An antenna array employing continuous transverse stubs as radiating elements, said antenna array comprising:

a planar rectangular sheet of dielectric material having two parallel broad surfaces separated by a predetermined distance;

a plurality of elongated raised relatively thin rectangular dielectric members integral with said sheet of dielectric material and extending transversely across one of the broad surfaces of said sheet of dielectric material, said plurality of thin rectangular dielectric members being evenly spaced from each other and regularly disposed along said sheet of dielectric material;

a conductive coating disposed on he exterior of said sheet of dielectric material and on the exterior of said plurality of thin rectangular dielectric members to define a parallel plate waveguide having a plurality of continuous transverse stubs disposed on one plate thereof, the surfaces of said plurality of thin rectangular dielectric members distal from said sheet of dielectric material being free from said conductive coating so as to define a plurality of radiating elements, one narrow side of said sheet of dielectric material being free from said conductive coating so as to define a feed for the antenna array; and

a plurality of non-radiating matching elements disposed between the continuous transverse stubs, wherein the cross-sectional shapes and relative locations off the non-radiating matching elements is chose to introduce a reflection coefficient within the parallel-plate waveguide that is substantially identical in magnitude and 180 degrees out of phase relative to the reflection coefficient associated with an adjacent radiating stub element that results in a cancellation of undesired reflections.

135. The antenna array of claim 134 wherein each of said transverse stubs is a longitudinal incidence stub element.

136. The antenna array of claim 134 with a parameter variation of said transverse stubs in a transverse direction.

137. The antenna array of claim 134 wherein each of said transverse stubs is a multi-stage stub element.

138. The antenna array of claim 134 wherein said transverse elements are paired elements to comprise a matched couplet.

139. The antenna array of claim 134 wherein radiating and non-radiating transverse stubs are pairs comprising a matched couplet.

140. The antenna array of claim 134 wherein said array provides circular polarization.

141. The antenna array of claim 134 wherein the array is a dual polarization antenna array.

142. The antenna array of claim 134 wherein the array is a squint-beam array.

143. The antenna array of claim 134 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thin conducting sheet.

144. The antenna array of claim 134 wherein the thickness of the conductive coating covering the parallel-plate waveguide between adjacent radiating stubs comprises a thick conducting plate having a thickness value substantially the same as height of the stubs.

145. The antenna array of claim 134 wherein the conductive coating comprises a solid homogeneous conductor.

146. The antenna array of claim 134 wherein the conductive coating comprises a hollow or inhomogeneously-filled cavity surrounded by thin conducting layers.

147. The antenna array of claim 134 wherein the conductive coating is formed in the shape of relatively long strips.

148. The antenna array of claim 134 wherein the conductive coating is formed in the shape of squares.

149. The antenna array of claim 134 wherein the non-radiating matching elements comprise extensions in the parallel-plate waveguide.

150. The antenna array of claim 134 which further comprises a superstrate disposed above the plurality of continuous transverse stubs.

151. The antenna array of claim 150 wherein the superstrate is comprised of at least one dielectric layer covering the antenna array.

152. The antenna array of claim 151 wherein the dielectric layer is formed from the group of dielectric materials including rexolite, polyethylene, stycast, lexan, air, and low-density foam.