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Transcript of 1 Antennas. Copyright © 2007 Oxford University Press Elements of Electromagnetics Fourth Edition...
1
Antennas
Elements of Electromagnetics Fourth Edition Sadiku 2Copyright © 2007 Oxford University Press
Source: Adapted with permission from M. Chryssomallis, “Smart Antennas,” IEEE Antennas and Propagation Magazine, vol. 42,no. 3, June 2000, pp. 129–136.
Elements of Electromagnetics Fourth Edition Sadiku 3Copyright © 2007 Oxford University Press
Figure 13.1 An antenna as a matching device between the guiding structure and the surrounding medium.
Elements of Electromagnetics Fourth Edition Sadiku 4Copyright © 2007 Oxford University Press
Figure 13.2 Typical antennas.
Elements of Electromagnetics Fourth Edition Sadiku 5Copyright © 2007 Oxford University Press
Figure 13.3 A Hertzian dipole carrying current I Io cos t.
Elements of Electromagnetics Fourth Edition Sadiku 6Copyright © 2007 Oxford University Press
Figure 13.4 (a) A half-wave dipole. (b) Geometry for calculating the fields.
Elements of Electromagnetics Fourth Edition Sadiku 7Copyright © 2007 Oxford University Press
Figure 13.5 The monopole antenna.
Elements of Electromagnetics Fourth Edition Sadiku 8Copyright © 2007 Oxford University Press
Figure 13.6 The small loop antenna.
Elements of Electromagnetics Fourth Edition Sadiku 9Copyright © 2007 Oxford University Press
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.
Elements of Electromagnetics Fourth Edition Sadiku 10Copyright © 2007 Oxford University Press
Figure 13.8 Power patterns of the Hertzian dipole: (a) constant 0, (b) constant /2.
Elements of Electromagnetics Fourth Edition Sadiku 11Copyright © 2007 Oxford University Press
Figure 13.9 Relating Pin, Pℓ, and Prad.
Elements of Electromagnetics Fourth Edition Sadiku 12Copyright © 2007 Oxford University Press
Figure 13.10 A two-element array.
Elements of Electromagnetics Fourth Edition Sadiku 13Copyright © 2007 Oxford University Press
Figure 13.11 An N-element uniform linear array.
Elements of Electromagnetics Fourth Edition Sadiku 14Copyright © 2007 Oxford University Press
Figure 13.12 Array factors for uniform linear arrays.
Elements of Electromagnetics Fourth Edition Sadiku 15Copyright © 2007 Oxford University Press
Figure 13.13 For part (a) of Example 13.6: field patterns in the plane containing the axes of the elements.
Elements of Electromagnetics Fourth Edition Sadiku 16Copyright © 2007 Oxford University Press
Figure 13.14 For part (b) of Example 13.6; field patterns in the plane containing the axes of the elements.
Elements of Electromagnetics Fourth Edition Sadiku 17Copyright © 2007 Oxford University Press
Figure 13.15 For Practice Exercise 13.6.
Elements of Electromagnetics Fourth Edition Sadiku 18Copyright © 2007 Oxford University Press
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.
Elements of Electromagnetics Fourth Edition Sadiku 19Copyright © 2007 Oxford University Press
Figure 13.17 For Example 13.7; obtaining the resultant group pattern of the three-element array of Figure 13.16(a).
Elements of Electromagnetics Fourth Edition Sadiku 20Copyright © 2007 Oxford University Press
Figure 13.18 For Example 13.7 and Practice Exercise 13.7: four-element array with current ratios 1: 3 : 3: 1.
Elements of Electromagnetics Fourth Edition Sadiku 21Copyright © 2007 Oxford University Press
Figure 13.19 For part (a) of Practice Exercise 13.7.
Elements of Electromagnetics Fourth Edition Sadiku 22Copyright © 2007 Oxford University Press
Figure 13.20 Thévenin equivalent of a receiving antenna.
Elements of Electromagnetics Fourth Edition Sadiku 23Copyright © 2007 Oxford University Press
Figure 13.21 Transmitting and receiving antennas in free space.
Elements of Electromagnetics Fourth Edition Sadiku 24Copyright © 2007 Oxford University Press
Figure 13.22 (a) Typical radar system. (b) Simplification of the system in (a) for calculating the target cross section.
Elements of Electromagnetics Fourth Edition Sadiku 25Copyright © 2007 Oxford University Press
Figure 13.23 Typical examples of intersystem EMI problems. Source: J. I. N. Violette et al., ElectromagneticCompatibility Handbook. New York: Van Nostrand Reinhold, 1987, p. 4.
Elements of Electromagnetics Fourth Edition Sadiku 26Copyright © 2007 Oxford University Press
Figure 13.24 Differences between conducted and radiated emissions.
Elements of Electromagnetics Fourth Edition Sadiku 27Copyright © 2007 Oxford University Press
Figure 13.25 Short dipole antenna with triangular current distribution; for Problem 13.5.
Elements of Electromagnetics Fourth Edition Sadiku 28Copyright © 2007 Oxford University Press
Figure 13.26 Two-element array of Problem 13.28.
Elements of Electromagnetics Fourth Edition Sadiku 29Copyright © 2007 Oxford University Press
Figure 13.27 For Problem 13.34.
Elements of Electromagnetics Fourth Edition Sadiku 30Copyright © 2007 Oxford University Press
Figure 13.28 For Problem 13.46.
Elements of Electromagnetics Fourth Edition Sadiku 31Copyright © 2007 Oxford University Press
Figure 13.29 For Problem 13.48.
