Electromagnetics

1. Electromagnetics

2. Logistics • Instructor:안병철 교수(bician@cbu.ac.kr) E10동611호(043-261-3194) • Graders:연걸, 장경월 (E10동519호, 043-261-3194) • Text: Fundamentals of Applied Electromagnetics – F. T. Ulaby (6th Edition) • Class: W10-11:50 am, F11-11:50am (E8-7동426호) • Self-study sessions: Friday class hour • HWs due: Beginning of class

3. Grading Info (Dates tentative)

4. Syllabus

5. Text/References교재: 전자기학, 7판, 김강욱, 김남, ...(Ulaby원저)

6. Caltech Physics Applets (http://hyperphysics.phy-astr.gsu.edu) On the Web Hyperphysics at Georgia Tech (http://hyperphysics.phy-astr.gsu.edu) Physics 2000 (UC Boulder) http://www.colorado.edu/physics/2000/index.pl http://www.falstad.com/mathphysics.html http://www.magnet.fsu.edu/education/tutorials/webresources.html

7. Do not forget Caltech Physics Applets (http://hyperphysics.phy-astr.gsu.edu) Hyperphysics at Georgia Tech (http://hyperphysics.phy-astr.gsu.edu) Wikipedia (http://www.wikipedia.org) How Stuff Works (http://www.howstuffworks.com)

8. Honor Policy Classroom Etiquette … as far as possible … Jeff Buchino http://www.cartoonclipart.com http://cartoonworks.gospelcom.net/clipart.html

9. Ch1-Overview

10. Maths Calculus Integration by change of variables Derivatives, Chain Rule Simple PDEs Trig sin2q, sin(A+B), cosA + cosB, sin2q + cos2q Geometry Area? Volume? Area? Perimeter? Area? Volume?

11. Six things to do before exams • Read day-to-day summaries for qualitative overview 2. Listen to lecture slide recordings 3. List important equations to remember 4. List important math formulae (calculus, trig) 5. Go over Mock Exam and solutions 6. Go over HWs and solutions Make sure you can do these (& similar!) problems ON YOUR OWN !! DO NOT LEAVE FOR THE LAST MOMENT!!

12. formula (포'뮬러) formulas, formulae (포'뮬리) stimulus stimuli (스티'뮬라이)

13. Six keys to success • Be regular 2. Try to understand, not memorize 3. Challenge yourself with the concepts 4. Brush up on maths (this is often the killer!) 5. Avoid careless mistakes at exam (CHECK!) 6. Revise

14. Why Electromagnetism? Rainbows Polaroids Lightning Northern Lights Telescope Laser Optics

15. Why Electromagnetism? Electronic Gadgets

16. Ion Channels Why Electromagnetism? Chemical Reactions Neural Impulses Biological Processes Chemistry and Biology

17. History of Electromagnetics Overview of the class New trends Topics to Discuss

18. Transmission Line LOAD How do EM Fields Propagate? • Transmission line equations • Characteristic impedance of a line • How much is reflected at a load? • How would one eliminate this reflection? • What about transient pulses?

19. + + + + + + + + + How do static charges interact? (Electrostatics) F2 F1 r Coulomb’s Law Force  q1q2/r2 q2 q1 Gauss’s Law Flux  q1 + q2 + .. Interaction in materials (Polarization)

20. E = lim F/q q  0 Vector Fields(A “disturbance in the force”) q

21. Non-negligible q Vector Fields(A disturbance in the force)

22. I1 i21 I dl2 i12 R I2 dl1 r H How do magnetic fields interact?(Magnetostatics) Biot-Savart’s Law Current  magnetic field H ~ I/r Another current senses it Force ~ i2 x H

23. I r H Time variation couples E and H Ampere’s Law Varying E produces H Faraday’s Law Varying H produces E

24. E E E E H H H Varying E produces H produces E produces H .. Faraday’s Law Ampere’s Law Coulomb/Gauss’ Law Gauss’ law for magnets Electrodynamics Maxwell’s Eqns.

25. Faraday’s Law Ampere’s Law Coulomb/Gauss’ Law Gauss’ law for magnets Electrodynamics Don’t worry about memorizing these yet – We will come back to these later. But meanwhile, let’s try to understand them qualitatively....

26. I r H Deciphering Maxwell’s equations Q Magnetic fields curl but don’t diverge Electric fields diverge but don’t curl

27. I r H Deciphering Maxwell’s equations Q Magnetic fields curl but don’t diverge (they loop on themselves since there are no magnetic poles) Electric fields diverge but don’t curl (they start and end on charges or ‘poles’)

28. I r H We thus have Maxwell’s equations in theirsimplest form (for static sources, in vacuum) Q Curl(H)  I Div(H) = 0 Div(E)  Q Curl(E) = 0 We will define Div and Curl precisely later on. For now, think of them as the number of diverging and curling lines respectively

29. E • E • E • E • H • H • H Note how E and H equations are independent of each other !! This is true for static sources For dynamic sources (time-dependent currents), you also get dH/dt terms for the E equations and dE/dt terms for the H equations, which couple them. • Varying E produces H produces E produces H .. We thus have Maxwell’s equations in theirsimplest form (for static sources, in vacuum) Curl(H)  I Div(H) = 0 Div(E)  Q Curl(E) = 0

30. Consequences of Maxwell’s equations Waves Radiation

31. Diffraction Polarization Interference Wave optics l > d

32. Lenses Mirrors Geometrical Optics l << d

33. What lies beyond Maxwell (1873)? For the aspiring scientists/engineers Will this be in your exams? NO

34. Nanoparticle opticsVisible light = 380-620nm

35. “Anomalous Optics”Negative refraction Laws are reversed ! Applications: Reverse Doppler, perfect lens

36. Quantum optics: Photonic Bandgap Materialsperiodic structure (period = half wavelength): total reflection at resonance, total transmission off ressonance

37. Cellphone interactions with head

38. Coherent optics – Laserscoherence = same frequency, constant phase difference; produces stationary interference Atomic Laser

39. Maxwell’s equations hold for all systems, from large objects to nanoscale… Solar Discharge (~1.4 x 109 m dia) Molecular fields (~10-8 m dia)

40. …. From ultrafast to ultraslow Optical Molasses/Condensates Slow light down from 1.02 billion km/hr to 1.6 km/hr !! (Lene Hau, Harvard physicist) Cerenkov Radiation (when a particle outruns its field) Optical equivalent of a sonic boom

41. Even in Sci-Fi !