1 / 75

Intensive Course on Electromagnetics Wave Propagation

Join this two-week course to learn wave propagation in material media, conductors, dielectrics, and magnetic materials. Explore charge densities, fields, and magnetization. Enhance your knowledge in fundamental electromagnetics concepts.

dickersonj
Download Presentation

Intensive Course on Electromagnetics Wave Propagation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Fundamentals of Electromagnetics:A Two-Week, 8-Day, Intensive Course for Training Faculty in Electrical-, Electronics-, Communication-, and Computer- Related Engineering Departments by Nannapaneni Narayana Rao Edward C. Jordan Professor Emeritus of Electrical and Computer Engineering University of Illinois at Urbana-Champaign, USA Distinguished Amrita Professor of Engineering Amrita Vishwa Vidyapeetham, India Amrita Viswa Vidya Peetham, Coimbatore August 11, 12, 13, 14, 18, 19, 20, and 21, 2008

  2. Module 5 • Wave Propagation in Material Media • Conductors and dielectrics • Magnetic materials • Wave equation and solution • Uniform waves in dielectrics and conductors • Boundary conditions

  3. Instructional Objectives • 17.Find the charge densities on the surfaces of infinite plane conducting slabs (with zero or nonzero net surface charge densities) placed parallel to infinite plane sheets of charge • 18. Find the displacement flux density, electric field intensity, and the polarization vector in a dielectric material in the presence of a specified charge distribution, for simple cases involving symmetry • 19. Find the magnetic field intensity, magnetic flux density, and the magnetization vector in a magnetic material in the presence of a specified current distribution, for simple cases involving symmetry

  4. Instructional Objectives (Continued) • Determine if the polarization of a specified electric/magnetic field in an anisotropic dielectric/magnetic material of permittivity/permeability matrix represents a characteristic polarization corresponding to the material • 21. Write expressions for the electric and magnetic fields of a uniform plane wave propagating away from an infinite plane sheet of a specified sinusoidal current density, in a material medium • 22. Find the material parameters from the propagation parameters of a sinusoidal uniform plane wave in a material medium • 23. Find the charge and current densities on a perfect conductor surface by applying the boundary conditions for the electric and magnetic fields on the surface • 24. Find the electric and magnetic fields at points on one side of a dielectric-dielectric interface, given the electric and magnetic fields at points on the other side of the interface

  5. Conductors • and Dielectrics • (FEME, Secs. 5.1; EEE6E, Secs. 4.1, 4.2)

  6. Materials Materials contain charged particles that under the application of external fields respond giving rise to three basic phenomena known as conduction, polarization, and magnetization. While these phenomena occur on the atomic or “microscopic”scale, it is sufficient for our purpose to characterize the material based on “macroscopic” scale observations, that is, observations averaged over volumes large compared with atomic dimensions. 8

  7. Material Media can be classified as • (1) Conductors • and Semiconductors • (2) Dielectrics • (3) Magnetic materials – magnetic property • Conductors and Semiconductors • Conductors are based upon the property of conduction, the phenomenon of drift of free electrons in the material with an average drift velocity proportional to the applied electric field. electric property

  8. In semiconductors, conduction occurs not only by electrons but also by holes – vacancies created by detachment of electrons due to breaking of covalent bonds with other atoms. The conduction current density is given by Ohm’s Law at a point

  9. conductors semiconductors

  10. s Ohm’s Law Ohm’s Law

  11. D4.1 • (a) For cu, • (b)

  12. (c) From

  13. Conductor in a static electric field

  14. rS0 E = – az –rS0 rS0 e0 rS= –e0E0 rS = e0E0 rS = –e0E0 rS = e0E0 rS = –e0E0 rS = e0E0

  15. rS1 rS2 • P4.3 • (a)

  16. rS11 rS12 rS21 rS22 • (b) Write two more equations and solve for the four unknowns.

  17. Dielectrics are based upon the property of polarization, which is the phenomenon of the creation of electric dipoles within the material. Electronic polarization: (bound electrons are displaced to form a dipole) Dipole moment p = Qd

  18. Orientational polarization: (Already existing dipoles are acted upon by a torque) Direction into the paper. Ionic polarization: (separation of positive and negative ions in molecules)

  19. The Permittivity Concept 11

  20. The phenomenon of polarization results in a polarization charge in the material which produces a secondary E.

  21. Polarization Current

  22. To take into account the effect of polarization, we define the displacement flux density vector, D, as vary with the material, implicitly taking into account the effect of polarization.

  23. As an example, consider Then, inside the material,

  24. D4.3 For 0 < z < d, (a)

  25. (b) (c)

  26. Isotropic Dielectrics: D is parallel to E for all E. Anisotropic Dielectrics: D is not parallel to E in general. Only for certain directions (or polarizations) of E is D parallel to E. These are known as characteristic polarizations.

  27. D4.4 (a)

  28. (b)

  29. (c)

  30. Magnetic Materials(FEME, Sec. 5.2; EEE6E, Sec. 4.3)

  31. Magnetic Materials are based upon the property of magnetization, which is the phenomenon of creation of magnetic dipoles within the material. Diamagnetism: A net dipole moment is induced by changing the angular velocities of the electronic orbits. Dipole moment m = IAan

  32. Paramagnetism Already existing dipoles are acted upon by a torque.

  33. The Permeability Concept , Magnetic Field Intensity 

  34. The phenomenon of magnetization results in a magnetization current in the material which produces a secondary B.

  35. Magnetization Current

  36. To take into account the effect of magnetization, we define the magnetic field intensity vector, H, as mr and m vary with the material, implicitly taking into account the effect of magnetization.

  37. As an example, consider Then inside the material,

  38. D4.6 For 0 < z < d, (a)

  39. (b) (c)

  40. Materials and Constitutive Relations Summarizing, Conductors Dielectrics Magnetic materials E and B are the fundamental field vectors. D and H are mixed vectors taking into account the dielectric and magnetic properties of the material implicity throughandm, respectively. 

  41. Wave Equation and Solution(FEME, Sec. 5.3; EEE6E, Sec. 4.4)

  42. Waves in Material Media

  43. Combining, we get Define Then Wave equation

  44. Solution:

  45. attenuation attenuation a = attenuation constant, Np/m b = phase constant, rad/m

  46. Summarizing, conversely,

More Related