1. 1 Antennas

2. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku2 Source: Adapted with permission from M. Chryssomallis, “Smart Antennas,” IEEE Antennas and Propagation Magazine, vol. 42, no. 3, June 2000, pp. 129–136.

3. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku3 Figure 13.1 An antenna as a matching device between the guiding structure and the surrounding medium.

4. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku4 Figure 13.2 Typical antennas.

5. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku5 Figure 13.3 A Hertzian dipole carrying current I  I o cos  t.

6. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku6 Figure 13.4 (a) A half-wave dipole. (b) Geometry for calculating the fields.

7. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku7 Figure 13.5 The monopole antenna.

8. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku8 Figure 13.6 The small loop antenna.

9. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku9 Figure 13.7 Field patterns of the Hertzian dipole: (a) normalized E-plane or vertical pattern (   constant  0), (b) normalized H-plane or horizontal pattern (    /2), (c) three-dimensional pattern.

10. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku10 Figure 13.8 Power patterns of the Hertzian dipole: (a)   constant  0, (b)   constant   /2.

11. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku11 Figure 13.9 Relating P in, P ℓ, and P rad.

12. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku12 Figure 13.10 A two-element array.

13. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku13 Figure 13.11 An N-element uniform linear array.

14. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku14 Figure 13.12 Array factors for uniform linear arrays.

15. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku15 Figure 13.13 For part (a) of Example 13.6: field patterns in the plane containing the axes of the elements.

16. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku16 Figure 13.14 For part (b) of Example 13.6; field patterns in the plane containing the axes of the elements.

17. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku17 Figure 13.15 For Practice Exercise 13.6.

18. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku18 Figure 13.16 For Example 13.7: (a) a three-element array with current ratios 1: 2 : 1; (b) and (c) equivalent two-element arrays.

19. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku19 Figure 13.17 For Example 13.7; obtaining the resultant group pattern of the three-element array of Figure 13.16(a).

20. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku20 Figure 13.18 For Example 13.7 and Practice Exercise 13.7: four-element array with current ratios 1: 3 : 3: 1.

21. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku21 Figure 13.19 For part (a) of Practice Exercise 13.7.

22. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku22 Figure 13.20 Thévenin equivalent of a receiving antenna.

23. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku23 Figure 13.21 Transmitting and receiving antennas in free space.

24. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku24 Figure 13.22 (a) Typical radar system. (b) Simplification of the system in (a) for calculating the target cross section .

25. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku25 Figure 13.23 Typical examples of intersystem EMI problems. Source: J. I. N. Violette et al., Electromagnetic Compatibility Handbook. New York: Van Nostrand Reinhold, 1987, p. 4.

26. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku26 Figure 13.24 Differences between conducted and radiated emissions.

27. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku27 Figure 13.25 Short dipole antenna with triangular current distribution; for Problem 13.5.

28. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku28 Figure 13.26 Two-element array of Problem 13.28.

29. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku29 Figure 13.27 For Problem 13.34.

30. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku30 Figure 13.28 For Problem 13.46.

31. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition Sadiku31 Figure 13.29 For Problem 13.48.