Lecture: 1 Introduction to Electromagnetics Engineering Dr. Yogesh Kumar Choukiker School of Electronics Science Engineering Department of Communication Engineering Microwave and Antenna Division VIT University, Vellore, India 1 COURSE OBJECTIVE To look into the origins of Electromagnetic Field Theory (EMFT) and major developments over the years To identify major technology areas and applications where knowledge of EMFT plays a vital role To prepare the mathematical foundations such as vector calculus and operators To study the laws governing static electric and magnetic fields To study the Maxwell’s equations and Time-varying nature of electric and magnetic fields On successful completion of the course, the student is expected to be in a position to study advanced courses such as ‘Antennas & Wave Propagation’ , ‘Microwave Theory & Techniques’ & ‘Communication Engineering’ etc OUR PLAN We have effectively 45 x 50 min. = 37.5 hours of theory lecture time to complete this course And 3 x 50 min. = 2.5 hours per week We have 14 lecture classes before CAT – I and 14 lecture classes thereafter till CAT - II and the remainder 17 lecture classes upto Term End Examination (TTE) In between CAT – I, CAT – II and TTE, we will have 3 Quizz papers and Assignments We will follow ‘Elements of Electromagnetics’ by Matthew N. O. Sadiku, 4/e. Any additional reference will be specified during classes What is Electromagnetism ?? The fundamental forces of nature that connect Matter and Energy can be defined by the interactions of elementary particles. Matter (Quarks, Leptons), Force Carriers (Gluons, W&Z Bosons, Photons, Gravitrons) Standard Model Of Physics Gravitational Electromagnetic Strong Nuclear Weak Nuclear Electromagnetics is the study of forces between elementary charged particles and their manifestation (fields, energy) Fundamental Fource PARTICLE /QUANTUM Strong nuclear gluon Electromagnetic photon W+,W- & Z Weak nuclear bosons gravitron Gravitation (tentative) FORCE 4 RELATIVE STRENGTH 1 7 X 10-3 MASS (GeV) 0.14 (?) none RANGE (meters) 10-15 infinite 10-5 80-90 10-17 6 X 10-39 none infinite The nucleus of an atom is bound by ‘Strong Nuclear’ force, which binds protons and neutrons together. Here the electromagnetic repulsion of ‘like-charged’ protons is smaller compared to ‘Strong Nuclear’ force. The ‘Weak Nuclear’ force results in transformation of protons to neutrons and vice versa, radioactive decay etc Gravitational force binds the galaxies, star systems etc Identification of Forces Hydro-electric power ? Gravitational Force Friction between objects ? Electromagnetic Force Nuclear Fusion/Fission ? Strong Nuclear Force Chemical Explosion ? Electromagnetic Force Solar Energy ? Strong Nuclear Force Pressure & Strain ? Electromagnetic Force -ray decay ? Weak Nuclear Force Tidal Energy ? Gravitational Force If you are curious to know more about the nature of forces refer to ‘Fundamental Forces of Nature : The Story of Gauge Fields’ by Kerson Huang Where Else Can I Find Electromagnetism ? Mobile Phones and many consumer electronic gadgets. Almost any device you plug into electrical mains works on electromagnetic principles Other Application Areas Plane wave hitting a ship. We study plane wave propagation in this course. This forms basis for studying Radar, Antennas etc Field Distribution Field Distribution Field Distribution Field Distribution Plane wave hitting various objects. We study plane wave propagation in this course. This forms basis for studying Radar, Antennas etc 5 Field Distribution Field Distribution Biological effects of Mobile Phones analysed using a Human Model. Field Distribution Field Distribution At system level, Electromagnetic Interference (EMI) among highly dense electronic packages is a very crucial problem Electromagnetic Compatibility (EMC) forms a major area of interest in Chip Industry, Power Transmission, Wireless Networks etc. Biological Effect of EM Radiation Biological effects of Mobile Phones analysed using a Human Model. EMI and EMC At system level, Electromagnetic Interference (EMI) among highly dense electronic packages is a very crucial problem Electromagnetic Compatibility (EMC) forms a major area of interest in Chip Industry, Power Transmission, Wireless Networks etc. Electrical Discharge Studying lightning strike and its effects on electrical systems and navigational aids carried on an aircraft Antenna & Radiation of EM Waves Radiation from a dielectric lens antenna for industrial radar Waveguides EM wave propagation through waveguide bends Electromagnetic Spectrum Some Fundamentals Force is an external stimulus on an object, that brings about motion of a body in rest or vice versa, change direction of motion or cause physical contraction or expansion. Force is measured in Newtons 1 N = 1 Kg m/s2 (remember Newton’s Laws of Motion ?) Energy is the capacity of a physical system or phenomena to carry out work. It can be in any form, electrical, mechanical, thermal, chemical, nuclear, light, acoustic etc Energy is measured in Joules 1 J = 1 N-m Power is rate of doing work or energy consumed per unit amount of time. Power is measured in Watts 1 W = 1 J/s Work is energy expended by a force to displace an object by unit distance. Work has same units as energy How can we relate them ?? Work is force applied on an object to displace it by a distance. Work = Force x Distance Work is also change of energy from one form into another Work = Energy By which we can say that Energy = Force x Distance Power is rate of doing work or rate at which energy is absorbed or expended. Power = Energy / time Similarly can you relate terms such as Momentum, Angular Momentum, Torque etc ? We will study the electrical equivalents of the mechanical concepts later Timeline and Pioneers 6th Century BC Thales of Miletus Rubbing fur on amber would cause an attraction between the two, Origin of static electricity 1st Century BC of some stones Shephard MagnesMagnetic properties 1600 AD William Gilbert bodies and earth as a big magnet Magnetic 1663 AD Otto von Guericke electrostatic generating machine First 1745 AD Pieter van Musschenbroek & Ewald Georg von Kleist First Capacitor Timeline and Pioneers 1752 AD Benjamin Franklin between lightning and electricity Establishes 1767 AD Joseph Priestley electrical inverse-square law Proposes link 1785 AD Charles-Augustine de Coulomb Inverse-square law of electrostatics 1791 AD Luigi Galvani Galvanic Battery Timeline and Pioneers 1799 AD Battery) Alessandro Volta Voltaic Cell (chemical 1820 AD Hans Christian Oersted Compass needle deflects when a battery nearby is switched on and off 1820 AD Andre Marie Ampere Coil of carrying current behaves like magnet (Solenoid) 1826 AD Georg Simon Ohm electrical resistance wire Ohm’s Law of Timeline and Pioneers 1831 AD Carl Friedrich Gauss Law of Flux densities Gauss’s Law or 1831 AD Telegraphy Magnetism Wilhelm Eduard Weber 1831 AD Michael Faraday electromagnetic induction Law and of 1833 AD Heinrich Friedrich Emil Lenz Increase or decrease of magnetic flux induces electromotive force Timeline and Pioneers 1835 AD Joseph Henry Electric relay Self 1837 AD Telegraphy, Morse Code Samuel Morse inductance, 1840 AD James Prescott Joule Joule’s Law, amount of heat produced in a circuit proportional to product of time, resitance and square of current 1854 AD Gustav Robert Kirchoff Conservation of electric charge and energy (Kirchoff’s Voltage, Current Laws) Timeline and Pioneers 1865 AD James Clerk Maxwell Maxwell’s equations linking electricity and magnetism, Father of electromagnetic theory 1878 AD light bulb Thomas Alva Edison Incandescent 1888 AD Heinrich Rudolf Hertz Radio wave propagation in free space and various media, experimental verification of Maxwell’s equations Timeline and Pioneers 1897 AD electron Joseph John Thomson 1905 AD Albert Einstein & Special Theory of Relativity Discovery of Speed of Light 1911 AD Heike Kammerlingh Onnes Superconductivity