Analysis of Crossed Dipole in Circular Cavity

The results of a crossed-dipole mounted in a cup Modern Antenna Design, 2ed, Wiley/IEEE Press, p. 246-247 have been extended over a range of dimensions. These designs are suitable as feeds for a reflector or useful in themselves. A full report showing their patterns and frequency responses is available as a download: cup_dipoles.

Summary of Results

Aperture
(λ)

Base
(λ)

Depth
(λ)

Gain
dB

Beam-
Width

Opt.
f/D

Illum.
Losses

Phase
Ctr. (λ)

Band-
Width

10 dB
Beam

0.6

0.6

0.3

6.4

85.6

0.32

1.70

0.332

22%

182.5

0.6

0.6

0.5

7.2

82.1

0.36

1.94

0.503

15.%

171.3

0.7

0.7

0.3

7.4

79.0

0.36

1.66

0.334

28%

162

0.7

0.7

0.5

8.0

73.4

0.40

1.73

0.486

20%

147.3

0.8

0.8

0.5

8.7

68.6

0.44

1.57

0.478

37%

133

0.88

0.57

0.44

9.1

65.2

0.48

1.48

0.415

21%

123.3

0.9

0.9

0.3

9.0

65.6

0.44

1.44

0.303

27%

128.4

0.9

0.9

0.4

9.2

63.9

0.44

1.49

0.393

28%

123.6

0.9

0.9

0.5

9.3

63.5

0.48

1.48

0.474

32%

121.6

0.9

0.9

0.6

9.3

64.7

0.48

1.47

0.566

44%

120.6

1.0

1.0

0.3

9.7

61.1

0.48

1.43

0.291

23%

118.0

1.0

1.0

0.3

9.6

61.5

0.48

1.44

0.287

27%

119.0

1.0

1.0

0.4

9.8

59.9

0.52

1.51

0.393

26%

115.1

1.0

1.0

0.5

10.0

58.7

0.48

1.44

0.480

29%

111.3

1.0

1.0

0.6

10.0

59.2

0.56

1.59

0.580

28%

111.0

1.0

0.65

0.5

9.8

61.1

0.48

1.43

0.455

25%

114.8

1.1

1.1

0.4

10.5

55.4

0.56

1.94

0.289

20%

105.5

1.1

1.1

0.5

10.7

54.1

0.56

1.47

0.491

20%

101.9

1.1

1.1

0.6

10.8

54.1

0.60

1.76

0.583

28%

100.8

1.2

0.65

0.5

10.7

54.2

0.52

1.36

0.395

33%

102.9

1.3

0.65

0.5

11.2

51.0

0.56

1.37

0.364

28.5%

97.3

1.4

0.65

0.5

11.5

49.1

0.60

1.58

0.249

29%

95.4

1.5

0.65

0.5

11.7

47.7

0.56

1.60

0.208

24%

94.3

1.6

0.65

0.44

11.3

47.9

0.56

1.52

0.132

23%

96.4

1.7

0.65

0.44

11.1

47.3

0.52

1.54

0.102

26.5%

96.9

1.7

0.80

0.44

11.6

45.2

0.60

1.61

0.050

26%

90.7

1.7

0.90

0.44

12.1

43.3

0.68

1.65

0.037

24.5%

85.7

1.7

1.0

0.44

12.5

41.4

0.68

1.79

-0.035

22.5%

81.8

1.7

1.1

0.44

12.6

39.4

0.64

2.10

-0.164

21%

83.6

1.8

1.0

0.44

12.6

39.7

0.56

2.02

-0.160

23%

84.8



Aperture
(λ)

Base
(λ)

Depth
(λ)

Dipole
Length

Dipole
Height

F/B
Center

F/B
Avg.

0.6

0.6

0.3

0.400

0.22

9.7

10.2

0.6

0.6

0.5

0.377

0.27

13.3

12.9

0.7

0.7

0.3

0.410

0.20

12.5

12.8

0.7

0.7

0.5

0.410

0.21

19.5

16.7

0.8

0.8

0.5

0.430

0.20

26.7

21.0

0.88

0.57

0.44

0.458

0.25

19.9

19.0

0.9

0.9

0.3

0.440

0.25

17.2

16.1

0.9

0.9

0.4

0.440

0.20

24.1

23.0

0.9

0.9

0.5

0.440

0.20

27.4

23.7

0.9

0.9

0.6

0.440

0.20

16.6

17.4

1.0

1.0

0.3

0.440

0.20

17.7

16.4

1.0

1.0

0.3

0.440

0.23

17.8

16.8

1.0

1.0

0.4

0.440

0.23

23.9

21.7

1.0

1.0

0.5

0.440

0.23

30.4

28.7

1.0

1.0

0.6

0.458

0.21

17.6

18.9

1.0

0.65

0.5

0.458

0.25

22.8

20.8

1.1

1.1

0.4

0.458

0.24

21.6

19.3

1.1

1.1

0.5

0.440

0.25

33.6

27.8

1.1

1.1

0.6

0.458

0.25

17.2

16.1

1.2

0.65

0.5

0.458

0.25

27.3

23.3

1.3

0.65

0.5

0.458

0.23

25.3

22.4

1.4

0.65

0.5

0.432

0.23

22.4

21.4

1.5

0.65

0.5

0.440

0.22

19.4

20.4

1.6

0.65

0.44

0.440

0.22

21.4

23.1

1.7

0.65

0.44

0.440

0.25

21.1

23.5

1.7

0.80

0.44

0.440

0.25

21.8

25.8

1.7

0.90

0.44

0.449

0.26

24.9

28.1

1.7

1.0

0.44

0.454

0.28

29.8

28.7

1.7

1.1

0.44

0.454

0.30

31.2

26.4

1.8

1.0

0.44

0.454

0.30

29.8

28.6