by Nannapaneni Narayana Rao Edward C. Jordan Professor Emeritus of Electrical and Computer Engineering University of Ill

1. Fundamentals of Electromagneticsfor Teaching and Learning:A Two-Week Intensive Course for Faculty inElectrical-, Electronics-, Communication-, and Computer- Related Engineering Departments in Engineering Colleges in India 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

2. Program for Hyderabad Area and Andhra Pradesh FacultySponsored by IEEE Hyderabad Section, IETE Hyderabad Center, and Vasavi College of EngineeringIETE Conference Hall, Osmania University CampusHyderabad, Andhra PradeshJune 3 – June 11, 2009Workshop for Master Trainer Faculty Sponsored byIUCEE (Indo-US Coalition for Engineering Education)Infosys Campus, Mysore, KarnatakaJune 22 – July 3, 2009

3. Introductory PresentationPart 2

4. Terminology Because I will be using the term “electrical and computer engineering” it is of interest to elaborate upon this terminology. In engineering departments in the United States educational institutions, electrical and computer engineering is generally one academic department, although not in all institutions. The name, ECEDHA, Electrical and Computer Engineering Department Heads Association, reflects this situation. In the College of Engineering at the University of Illinois at Urbana-Champaign (UIUC), the Department of Electrical and Computer Engineering (ECE) offers two undergraduate programs leading to the Bachelor of Science degrees: Electrical Engineering and Computer Engineering.

5. The Scope of Electrical Engineering “A list of the twenty greatest engineering achievements of the twentieth century compiled by the National Academy of Engineering includes ten achievements primarily related to the field of electrical engineering: electrification, electronics, radio and television, computers, telephone, internet, imaging, household appliances, health technologies, and laser and fiber optics. The remaining achievements in the list - automobile, airplane, water supply and distribution, agricultural mechanization, air conditioning and refrigeration, highways, spacecraft, petroleum/petrochemical technologies, nuclear technologies, and high-performance materials - also require knowledge of electrical engineering to differing degrees. In the twenty-first century the discipline of electrical engineering continues to be one of the primary drivers of change and progress in technology and standards of living around the globe.”

6. Electrification Automobile Airplane Water Supply & Distribution Electronics Radio & Television Agricultural Mechanization Computers Telephone Air Conditioning & Refrigeration Highways Spacecraft Internet Imaging Household Appliances Health Technologies Petroleum/Petrochemical Technologies Laser & Fiber Optics Nuclear Technologies High-Performance Materials NAE’s List of Greatest Engineering Achievements of the 20th Century Red indicates areas where ECE at UIUC has had influence.

7. The Scope of Computer Engineering “Computer engineering is a discipline that applies principles of physics and mathematics to the design, implementation, and analysis of computer and communication systems. The discipline is broad, spanning topics as diverse as radio communications, coding and encryption, computer architecture, testing and analysis of computer and communication systems, vision, and robotics. A defining characteristic of the discipline is its grounding in physical aspects of computer and communication systems. Computer engineering concerns itself with development of devices that exploit physical phenomena to store and process information, with the design of hardware that incorporates such devices, and with software that takes advantage of this hardware's characteristics. It addresses problems in design, testing, and evaluation of system properties, such as reliability, and security. It is an exciting area to work in, one that has immediate impact on the technology that shapes society today.”

8. The Illinois Curriculum in Electrical Engineering For the electrical engineering program at Illinois, the core curriculum focuses on fundamental electrical engineering knowledge: circuits, systems, electromagnetics, solid state electronics, computer engineering, and design. A rich set of elective courses permits students to select from collections of courses in seven areas of electrical and computer engineering: bioengineering, acoustics, and magnetic resonance engineering; circuits and signal processing; communication and control; computer engineering; electromagnetics, optics, and remote sensing; microelectronics and quantum electronics; power and energy systems.

9. The Illinois Curriculum in Computer Engineering For the computer engineering program, the core curriculum focuses on fundamental computer engineering knowledge: circuits, systems, electromagnetics, computer engineering, solid state electronics, and computer science. A rich set of elective courses permits students to concentrate in any sub-discipline of computer engineering including: computer systems; electronic circuits; networks; engineering applications; software, languages, and theory; and algorithms and mathematical tools.

10. Electromagnetics is all around us! In simple terms, every time we turn a switch on for electrical power or for an electronic equipment, every time we press a key on our computer key board or on our cell phone, or every time we perform a similar action involving an everyday electrical device, electromagnetics comes into play.

11. Physics Based Signal Processing & Imaging Biomedical Engineering & BioTech Computer Chip Design & Circuits Lasers & Optoelectronics Wireless Comm. & Propagation MEMS & Microwave Engineering ELECTROMAGNETICS RCS Analysis, Design, ATR & Stealth Technology Remote Sensing & Subsurface Sensing & NDE Antenna Analysis & Design EMC/EMI Analysis Some modern applications of EM (Courtesy of Weng C. Chew)

12. Fundamental to the Study of ECE It is the foundation for the technologies of electrical and computer engineering, spanning the entire electromagnetic spectrum, from dc to light. As such, in the context of engineering education, it is fundamental to the study of electrical and computer engineering.

13. Foundation for the technologies of electrical and computer engineering

14. Fundamental to the Study of ECE In 1963, the American Institute of Electrical Engineers (AIEE) and the Institute of Radio Engineers (IRE) were merged into the Institute of Electrical and Electronics Engineers (IEEE), a global nonprofit organization with over 375,000 members, and “the world's leading professional association for the advancement of technology.” The IEEE logo or badge is a merger of the badges of the two parent organizations. It contains a vertical arrow surrounded by a circular arrow, within a kite-shaped border. No letters clutter the badge because a badge without letters can be read in any language. The AIEE badge had the kite shape which was meant to symbolize the kite from Benjamin Franklin’s famous kite experiment to study electricity. The IRE badge had the two arrows that symbolize the right hand rule of electromagnetism.

15. Fundamental to the Study of ECE Alternatively, the vertical arrow can be thought of as representing one of the two fields, electric or magnetic, and the circular arrow surrounding it representing the second field, produced by it, so that together they represent an electromagnetic field.

16. Fundamental to the Study of ECE Whether this logo of IEEE was intended to be a recognition of the fact that electromagnetics is fundamental to all of electrical and computer engineering, it is a fact that all electrical phenomena are governed by the laws of electromagnetics, and hence, the study of electromagnetics is essential to all branches of electrical and computer engineering, and indirectly impacts many other branches.

17. EM is so fundamental that even Mac “Circuits” Van Valkenburg was caught having fun “communicating” the RH Rule to Robert “Communications” Lucky! Wonderful picture!

18. An amusing incident One of the earliest postwar programs to be established at UIUC was a program in radio direction finding (RDF). It was intended as a basic research program, sponsored by the Office of Naval Research. When the sponsor was asked by the research supervisor, Edward Jordan, what facets of the field might be of particular interest, the answer received was: “Look, you know Maxwell’s equations, the Russians know Maxwell’s equations; you take it from there.” Jordan was amused that it would be difficult to get more basic than that.

19. Wullenweber Array at Bondville Road Field Station of the RDF Laboratory • Used in Radio Direction Finding Laboratory • In operation 1955-1980 • Used 120 antennas and was 1000 ft in diameter • Operated in frequency range of 4-16 MHz

20. Wullenweber array of the RDF Laboratory (1955 – 1980)

21. Discovering Wullenweber while riding the Pineapple Express at the Dole Plantation on the island of Oahu, Hawaii, with family on June 4, 2005, as a reminder

22. Wullenweber and Bananas (My favorite slide)

23. So, what is Electromagnetics? By the very nature of the word, electromagnetics implies having to do with a phenomenon involving both electric and magnetic fields and furthermore coupled. This is indeed the case when the situation is dynamic, that is, time-varying, because time-varying electric and magnetic fields are interdependent, with one field producing the other.

24. What is Electromagnetics? In other words, a time-varying electric field or a time-varying magnetic field cannot exist alone; the two fields coexist in time and space, with the space-variation of one field governed by the time-variation of the second field. This is the essence of Faraday’s law and Ampere’s circuital law, the first two of the four Maxwell’s equations resulting in wave propagation.

25. About Electromagnetics (Continued) Only when the fields are not changing with time, that is, for the static case, they are independent; a static electric field or a static magnetic field can exist alone, with the exception of one case in which there is a one-way coupling, electric field resulting in magnetic field, but not the other way.

26. About Electromagnetics (Continued) Thus, in the entire frequency spectrum, except for dc, all electrical phenomena are, in the strictest sense, governed by interdependent electric and magnetic fields, or electromagnetic fields.

27. Quasistatic Approximation However, at low frequencies, an approximation, known as the “quasistatic approximation,” can be made in which the time-varying fields in a physical structure are approximated to have the same spatial variations as the static fields in the structure obtained by setting the source frequency equal to zero.

28. Quasistatic Approximation (Continued) Thus, although the actual situation in the structure is one of electromagnetic wave nature, it is approximated by a dynamic but not wavelike nature. As the frequency becomes higher and higher, this approximation violates the actual situation more and more, and it becomes increasingly necessary to consider the wave solution.

29. Statics: f = 0;;dc Dynamics: No restriction; complete Maxwell’s equations; Electromagnetic waves Quasistatics: Low-frequency extension of statics, or low-frequency approximation of dynamics;

30. Maxwell’s Equations are elegant and beautiful. As profound as they are, they are actually quite simple to explain and understand.

31. × ò ò D d S = r dv S V Maxwell’s Equations d × × ò E d l = – ò B d S dt C S Charge density Magnetic flux density Electric field intensity d × × × × ò B d S = 0 ò ò ò H d l = J d S + D d S dt S C S S Current density Magnetic field intensity Displacement flux density

32. Faraday’s Law, the first EMantra Electromotive Force (emf) or voltage around C = Negative of the time rate of increase of the magnetic flux crossing S bounded by C.

33. Voltage around C, also known as electromotive force (emf) around C (but not really a force), = Magnetic flux crossing S, = Time rate of decrease of magnetic flux crossing S,

34. Ampere’s Circuital Law, the second EMantra Magnetomotive force (mmf) around C = Current due to flow of charges crossing S bounded by C + Time rate of increase of electric (or displacement) flux crossing S

35. = Magnetomotive force (only by analogy with electromotive force), = Current due to flow of charges crossing S, = Displacement flux, or electric flux, crossing S,

36. = Time rate of increase of displacement flux crossing S, or, displacement current crossing S,

37. Gauss’ Law for the Electric Field, the third EMantra Displacement flux emanating from a closed surface S = charge contained in the volume V bounded by S = charge enclosed by S r

38. Gauss’ Law for the Magnetic Field, the fourth EMantra Magnetic flux emanating from a closed surface S = 0.

39. Out of the four EMantras, only the first two, Faraday’s and Ampere’s circuital laws are independent. The fourth Mantra, Gauss’ law for the magnetic field, follows from Faraday’s law, and the third Mantra, Gauss’ law for the electric field, follows from Ampere’s circuital law, with the aid of an auxiliary equation, the law of conservation of charge.

40. Law of Conservation of Charge, an auxiliary EMantra r(t) Current due to flow of charges emanating from a closed surface S = Time rate of decrease of charge enclosed by S.

41. ¶ B Ñ x E = – ¶ t ¶ D Ñ x H = J + ¶ t Maxwell’s Equations in Differential Form and the Continuity Equation Faraday’s Law Ampere’s Circuital Law Gauss’ Law for the Electric Field Gauss’ Law for the Magnetic Field Continuity Equation

42. Time derivatives of the components of B Lateral space derivatives of the components of E Charge density

43. The “Mahatmyam (Greatness)” of Maxwell’s Equations

44. The “Mahatmyam (Greatness)” of Maxwell’s Equations Ampere’s Circuital Law Law of Conservation of Charge Faraday’s Law  Gauss’ Law for E

45. The “Mahatmyam (Greatness)” of Maxwell’s Equations Thus, Faraday's law says that a time-varying magnetic field gives rise to an electric field, the space-variation of which is related to the time-variation of the magnetic field.  Ampere's circuital law tells us that a time-varying electric field produces a magnetic field, the space variation of which is related to the time-variation of the electric field.  Thus, if one time-varying field is generated, it produces the second one, which in turn gives rise to the first one, and so on, which is the phenomenon of electromagnetic wave propagation, characterized by time delay of propagation of signals. In addition, Ampere’s circuital law tells us that an electric current produces a magnetic field, so that a time-varying current source results in a time-varying magnetic field, beginning the process of one field generating the second.

46. Hertzian Dipole

47. Radiation from Hertzian Dipole

48. Hertzian dipole and radiation pattern on the covers of the U.S. and Indian Editions of “Fundamentals of Electromagnetics”

49. The Contribution of Maxwell You will have noted that none of the four equations are named after Maxwell. So, the question arises as to why they are known as Maxwell’s equations. It is because of a purely mathematical contribution of Maxwell. This mathematical contribution is the second term on the right side of Ampere’s circuital law. Prior to that, Ampere’s circuital law consisted of only the first term on the right side.

50. The Contribution of Maxwell Without the second term on the right side of Ampere’s circuital law, the loop is not complete and hence there is no interdependence of time-varying electric and magnetic fields and no EM waves!