Plane Wave – Normal Incidence Plane Wave – Normal Incidence Introduction
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Ec6503 - Transmission Lines and Waveguides Transmission Lines and Waveguides Unit I - Transmission Line Theory 1
EC6503 - TRANSMISSION LINES AND WAVEGUIDES TRANSMISSION LINES AND WAVEGUIDES UNIT I - TRANSMISSION LINE THEORY 1. Define – Characteristic Impedance [M/J–2006, N/D–2006] Characteristic impedance is defined as the impedance of a transmission line measured at the sending end. It is given by 푍 푍0 = √ ⁄푌 where Z = R + jωL is the series impedance Y = G + jωC is the shunt admittance 2. State the line parameters of a transmission line. The line parameters of a transmission line are resistance, inductance, capacitance and conductance. Resistance (R) is defined as the loop resistance per unit length of the transmission line. Its unit is ohms/km. Inductance (L) is defined as the loop inductance per unit length of the transmission line. Its unit is Henries/km. Capacitance (C) is defined as the shunt capacitance per unit length between the two transmission lines. Its unit is Farad/km. Conductance (G) is defined as the shunt conductance per unit length between the two transmission lines. Its unit is mhos/km. 3. What are the secondary constants of a line? The secondary constants of a line are 푍 i. Characteristic impedance, 푍0 = √ ⁄푌 ii. Propagation constant, γ = α + jβ 4. Why the line parameters are called distributed elements? The line parameters R, L, C and G are distributed over the entire length of the transmission line. Hence they are called distributed parameters. They are also called primary constants. The infinite line, wavelength, velocity, propagation & Distortion line, the telephone cable 5. What is an infinite line? [M/J–2012, A/M–2004] An infinite line is a line where length is infinite. -
Physics-272 Lecture 21
Physics-272Physics-272 Lecture Lecture 21 21 Description of Wave Motion Electromagnetic Waves Maxwell’s Equations Again ! Maxwell’s Equations James Clerk Maxwell (1831-1879) • Generalized Ampere’s Law • And made equations symmetric: – a changing magnetic field produces an electric field – a changing electric field produces a magnetic field • Showed that Maxwell’s equations predicted electromagnetic waves and c =1/ √ε0µ0 • Unified electricity and magnetism and light . Maxwell’s Equations (integral form) Name Equation Description Gauss’ Law for r r Q Charge and electric Electricity ∫ E ⋅ dA = fields ε0 Gauss’ Law for r r Magnetic fields Magnetism ∫ B ⋅ dA = 0 r r Electrical effects dΦB from changing B Faraday’s Law ∫ E ⋅ ld = − dt field Ampere’s Law r Magnetic effects dΦE from current and (modified by ∫ B ⋅ dl = µ0ic + ε0 Maxwell) dt Changing E field All of electricity and magnetism is summarized by Maxwell’s Equations. On to Waves!! • Note the symmetry now of Maxwell’s Equations in free space, meaning when no charges or currents are present r r r r ∫ E ⋅ dA = 0 ∫ B ⋅ dA = 0 r r dΦ r dΦ ∫ E ⋅ ld = − B B ⋅ dl = µ ε E dt ∫ 0 0 dt • Combining these equations leads to wave equations for E and B, e.g., ∂2E ∂ 2 E x= µ ε x ∂z20 0 ∂ t 2 • Do you remember the wave equation??? 2 2 ∂h1 ∂ h h is the variable that is changing 2= 2 2 in space (x) and time ( t). v is the ∂x v ∂ t velocity of the wave. Review of Waves from Physics 170 2 2 • The one-dimensional wave equation: ∂h1 ∂ h 2= 2 2 has a general solution of the form: ∂x v ∂ t h(x,t) = h1(x − vt ) + h2 (x + vt ) where h1 represents a wave traveling in the +x direction and h2 represents a wave traveling in the -x direction. -
EE1.El3 (EEE1023): Electronics III Acoustics Lecture 12 Principles Of
EE1.el3 (EEE1023): Electronics III Acoustics lecture 12 Principles of sound Dr Philip Jackson www.ee.surrey.ac.uk/Teaching/Courses/ee1.el3 Overview for this semester 1. Introduction to sound 2. Human sound perception 3. Noise measurement 4. Sound wave behaviour 5. Reflections and standing waves 6. Room acoustics 7. Resonators and waveguides 8. Musical acoustics 9. Sound localisation L.1 Introduction to sound • Definition of sound • Vibration of matter { transverse waves { longitudinal waves • Sound wave propagation { plane waves { pure tones { speed of sound L.2 Preparation for Acoustics • What is a sound wave? { look up a definition of sound and its properties • Example of a device for manipulating sound { write down or draw your example { explain how it modifies the sound L.3 Definitions of sound \Sensation caused in the ear by the vibration of the surrounding air or other medium", Oxford En- glish Dictionary \Disturbances in the air caused by vibrations, in- formation on which is transmitted to the brain by the sense of hearing", Chambers Pocket Dictionary \Sound is vibration transmitted through a solid, liquid, or gas; particularly, sound means those vi- brations composed of frequencies capable of being detected by ears", Wikipedia L.4 Vibration of a string Let us consider forces on an element of the vibrating string with tension T and ρL mass per unit length, to derive its equation of motion T y + dy dx dx y ds θ dy x y dx T x x + dx Net vertical force from tension between points x and x + dx: dFY = (T sin θ)x+dx − (T sin θ)x (1) Taylor -
Waveguides Waveguides, Like Transmission Lines, Are Structures Used to Guide Electromagnetic Waves from Point to Point. However
Waveguides Waveguides, like transmission lines, are structures used to guide electromagnetic waves from point to point. However, the fundamental characteristics of waveguide and transmission line waves (modes) are quite different. The differences in these modes result from the basic differences in geometry for a transmission line and a waveguide. Waveguides can be generally classified as either metal waveguides or dielectric waveguides. Metal waveguides normally take the form of an enclosed conducting metal pipe. The waves propagating inside the metal waveguide may be characterized by reflections from the conducting walls. The dielectric waveguide consists of dielectrics only and employs reflections from dielectric interfaces to propagate the electromagnetic wave along the waveguide. Metal Waveguides Dielectric Waveguides Comparison of Waveguide and Transmission Line Characteristics Transmission line Waveguide • Two or more conductors CMetal waveguides are typically separated by some insulating one enclosed conductor filled medium (two-wire, coaxial, with an insulating medium microstrip, etc.). (rectangular, circular) while a dielectric waveguide consists of multiple dielectrics. • Normal operating mode is the COperating modes are TE or TM TEM or quasi-TEM mode (can modes (cannot support a TEM support TE and TM modes but mode). these modes are typically undesirable). • No cutoff frequency for the TEM CMust operate the waveguide at a mode. Transmission lines can frequency above the respective transmit signals from DC up to TE or TM mode cutoff frequency high frequency. for that mode to propagate. • Significant signal attenuation at CLower signal attenuation at high high frequencies due to frequencies than transmission conductor and dielectric losses. lines. • Small cross-section transmission CMetal waveguides can transmit lines (like coaxial cables) can high power levels. -
Music 170 Assignment 7 1. a Sinusoidal Plane Wave at 20 Hz
Music 170 assignment 7 1. A sinusoidal plane wave at 20 Hz. has an SPL of 80 decibels. What is the RMS displacement (in millimeters.) of air (in other words, how far does the air move)? 2. A rectangular vibrating surface one foot long is vibrating at 2000 Hz. Assuming the speed of sound is 1000 feet per second, at what angle off axis should the beam's amplitude drop to zero? 3. How many dB less does a cardioid microphone pick up from an incoming sound 90 degrees (π=2 radians) off-axis, compared to a signal coming in frontally (at the angle of highest gain)? 4. Suppose a sound's SPL is 0 dB (i.e., it's about the threshold of hearing at 1 kHz.) What is the total power that you ear receives? (Assume, a bit generously, that the opening is 1 square centimeter). 5. If light moves at 3 · 108 meters per second, and if a certain color has a wavelength of 500 nanometers (billionths of a meter - it would look green to human eyes), what is the frequency? Would it be audible if it were a sound? [NOTE: I gave the speed of light incorrectly (mixed up the units, ouch!) - we'll accept answers based on either the right speed or the wrong one I first gave.] 6. A speaker one meter from you is paying a tone at 440 Hz. If you move to a position 2 meters away (and then stop moving), at what pitch to you now hear the tone? (Hint: don't think too hard about this one). -
Wave Guides Summary and Problems
ECE 144 Electromagnetic Fields and Waves Bob York General Waveguide Theory Basic Equations (ωt γz) Consider wave propagation along the z-axis, with fields varying in time and distance according to e − . The propagation constant γ gives us much information about the character of the waves. We will assume that the fields propagating in a waveguide along the z-axis have no other variation with z,thatis,the transverse fields do not change shape (other than in magnitude and phase) as the wave propagates. Maxwell’s curl equations in a source-free region (ρ =0andJ = 0) can be combined to give the wave equations, or in terms of phasors, the Helmholtz equations: 2E + k2E =0 2H + k2H =0 ∇ ∇ where k = ω√µ. In rectangular or cylindrical coordinates, the vector Laplacian can be broken into two parts ∂2E 2E = 2E + ∇ ∇t ∂z2 γz so that with the assumed e− dependence we get the wave equations 2E +(γ2 + k2)E =0 2H +(γ2 + k2)H =0 ∇t ∇t (ωt γz) Substituting the e − into Maxwell’s curl equations separately gives (for rectangular coordinates) E = ωµH H = ωE ∇ × − ∇ × ∂Ez ∂Hz + γEy = ωµHx + γHy = ωEx ∂y − ∂y ∂Ez ∂Hz γEx = ωµHy γHx = ωEy − − ∂x − − − ∂x ∂Ey ∂Ex ∂Hy ∂Hx = ωµHz = ωEz ∂x − ∂y − ∂x − ∂y These can be rearranged to express all of the transverse fieldcomponentsintermsofEz and Hz,giving 1 ∂Ez ∂Hz 1 ∂Ez ∂Hz Ex = γ + ωµ Hx = ω γ −γ2 + k2 ∂x ∂y γ2 + k2 ∂y − ∂x w W w W 1 ∂Ez ∂Hz 1 ∂Ez ∂Hz Ey = γ + ωµ Hy = ω + γ γ2 + k2 − ∂y ∂x −γ2 + k2 ∂x ∂y w W w W For propagating waves, γ = β,whereβ is a real number provided there is no loss. -
Uniform Plane Waves
38 2. Uniform Plane Waves Because also ∂zEz = 0, it follows that Ez must be a constant, independent of z, t. Excluding static solutions, we may take this constant to be zero. Similarly, we have 2 = Hz 0. Thus, the fields have components only along the x, y directions: E(z, t) = xˆ Ex(z, t)+yˆ Ey(z, t) Uniform Plane Waves (transverse fields) (2.1.2) H(z, t) = xˆ Hx(z, t)+yˆ Hy(z, t) These fields must satisfy Faraday’s and Amp`ere’s laws in Eqs. (2.1.1). We rewrite these equations in a more convenient form by replacing and μ by: 1 η 1 μ = ,μ= , where c = √ ,η= (2.1.3) ηc c μ Thus, c, η are the speed of light and characteristic impedance of the propagation medium. Then, the first two of Eqs. (2.1.1) may be written in the equivalent forms: ∂E 1 ∂H ˆz × =− η 2.1 Uniform Plane Waves in Lossless Media ∂z c ∂t (2.1.4) ∂H 1 ∂E The simplest electromagnetic waves are uniform plane waves propagating along some η ˆz × = ∂z c ∂t fixed direction, say the z-direction, in a lossless medium {, μ}. The assumption of uniformity means that the fields have no dependence on the The first may be solved for ∂zE by crossing it with ˆz. Using the BAC-CAB rule, and transverse coordinates x, y and are functions only of z, t. Thus, we look for solutions noting that E has no z-component, we have: of Maxwell’s equations of the form: E(x, y, z, t)= E(z, t) and H(x, y, z, t)= H(z, t). -
Anharmonic Waves in Quantum Electrodynamics
Anharmonic Waves in Field Theory F. J. Himpsel Physics Department, University of Wisconsin Madison, Madison WI 53706, USA Abstract This work starts from the premise that sinusoidal plane waves cease to be solutions of field theories when turning on an interaction. A nonlinear interaction term generates harmonics analogous to those observed in nonlinear optical media. This calls for a generalization to anharmonic waves in both classical and quantum field theory. Three simple requirements make anharmonic waves compatible with relativistic field theory and quantum physics. Some non-essential concepts have to be abandoned, such as orthogonality, the superposition principle, and the existence of single-particle energy eigenstates. The most general class of anharmonic waves allows for a zero frequency term in the Fourier series, which corresponds to a quantum field with a non-zero vacuum expectation value. Anharmonic quantum fields are defined by generalizing the expansion of a field operator into creation and annihilation operators. This method provides a framework for handling exact quantum fields, which define exact single particle states. ____________________________________ Electronic address: [email protected] 1 Contents 1. General Concept 3 2. Criteria for Anharmonic Waves 5 3. Fourier Series of Anharmonic Waves 6 4. Symmetry Classes 8 5. Energy and Momentum 10 6. Orthonormality and Completeness 12 7. Anharmonic Quantum Fields 13 8. Conclusions and Outlook 16 Appendix A: Fourier Coefficients and Anharmonicity Parameter 17 Appendix B: Expansion of Sinusoidal Waves into Anharmonic Waves 19 Appendix C: Simple Anharmonic Waves 20 Appendix D: Anharmonic Waves from Elliptic Functions 22 Appendix E: Anharmonic Waves from Differential Equations and Lagrangians 25 References 28 2 1. -
Wave Equation
UNIVERSITY OF OSLO INF5410 Array signal processing. Chapter 2.1-2.2: Wave equation Sverre Holm DEPARTMENT OF INFORMATICS UNIVERSITY OF OSLO Chapters in Johnson & Dungeon • Ch. 1: Introduction . • Ch. 2: Signals in Space and Time. – Physics: Waves and wave equation. »c, λ, f, ω, k vector,... » Ideal and ”real'' conditions • Ch. 3: Apertures and Arrays. • Ch4BCh. 4: Beam form ing. – Classical, time and frequency domain algorithms. • Ch. 7: Adaptive Array Processing. DEPARTMENT OF INFORMATICS 2 1 UNIVERSITY OF OSLO Norsk terminologi • Bølgeligningen • Planbølger, sfæriske bølger • Propagerende bølger, bølgetall • Sinking/sakking: • Dispersjon • Attenuasjon eller demping • Refraksjon • Ikke-linearitet • Diffraksjon; nærfelt, fjernfelt • Gruppeantenne ( = array) Kilde: Bl.a. J. M. Hovem: ``Marin akustikk'', NTNU, 1999 DEPARTMENT OF INFORMATICS 3 UNIVERSITY OF OSLO Wave equation • This is the equation in array signal processing. • Lossless wave equation • Δ=∇2 is the Laplacian operator (del=nabla squared) • s = s(x,y,z,t) is a general scalar field (electromagnetics: electric or magnetic field, acoustics: sound pressure ...) • c is the speed of propagation DEPARTMENT OF INFORMATICS 4 2 UNIVERSITY OF OSLO Three simple principles behind the acoustic wave equation dz 1. Equation of continuity: ∂(ρu& x ) ρu& x + dx conservation of mass ∂x ρu& x 2. Newton’s 2. law: F = m a 3. State equation: relationship between change in pressure and z dy volume (in one dimension this y dx is Hooke’s law: F = k x – spring) x Figure: J Hovem, TTT4175 Marin akustikk, -
DESIGN of DIFFRACTIVE OPTICAL ELEMENTS: OPTIMALITY, SCALE and NEAR-FIELD DIFFRACTION CONSIDERATIONS Parker Kuhl
Purdue University Purdue e-Pubs ECE Technical Reports Electrical and Computer Engineering 1-1-2003 DESIGN OF DIFFRACTIVE OPTICAL ELEMENTS: OPTIMALITY, SCALE AND NEAR-FIELD DIFFRACTION CONSIDERATIONS Parker Kuhl Okan K. Ersoy Follow this and additional works at: http://docs.lib.purdue.edu/ecetr Kuhl, Parker and Ersoy, Okan K. , "DESIGN OF DIFFRACTIVE OPTICAL ELEMENTS: OPTIMALITY, SCALE AND NEAR- FIELD DIFFRACTION CONSIDERATIONS" (2003). ECE Technical Reports. Paper 151. http://docs.lib.purdue.edu/ecetr/151 This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for additional information. DESIGN OF DIFFRACTIVE OPTICAL ELEMENTS: OPTIMALITY, SCALE AND NEAR-FIELD DIFFRACTION CONSIDERATIONS Parker Kuhl Okan K. Ersoy TR-ECE 03-09 School of Electrical and Computer Engineering 465 Northwestern Avenue Purdue University West Lafayette, IN 47907-2035 ii iii TABLE OF CONTENTS LIST OF TABLES .............................................................................................................v LIST OF FIGURES ........................................................................................................ vii ABSTRACT.......................................................................................................................ix 1 INTRODUCTION......................................................................................................... 1 2. DIFFRACTION .......................................................................................................... -
Microstrip Solutions for Innovative Microwave Feed Systems
Examensarbete LiTH-ITN-ED-EX--2001/05--SE Microstrip Solutions for Innovative Microwave Feed Systems Magnus Petersson 2001-10-24 Department of Science and Technology Institutionen för teknik och naturvetenskap Linköping University Linköpings Universitet SE-601 74 Norrköping, Sweden 601 74 Norrköping LiTH-ITN-ED-EX--2001/05--SE Microstrip Solutions for Innovative Microwave Feed Systems Examensarbete utfört i Mikrovågsteknik / RF-elektronik vid Tekniska Högskolan i Linköping, Campus Norrköping Magnus Petersson Handledare: Ulf Nordh Per Törngren Examinator: Håkan Träff Norrköping den 24 oktober, 2001 'DWXP $YGHOQLQJ,QVWLWXWLRQ Date Division, Department Institutionen för teknik och naturvetenskap 2001-10-24 Ã Department of Science and Technology 6SUnN 5DSSRUWW\S ,6%1 Language Report category BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB Svenska/Swedish Licentiatavhandling X Engelska/English X Examensarbete ISRN LiTH-ITN-ED-EX--2001/05--SE C-uppsats 6HULHWLWHOÃRFKÃVHULHQXPPHUÃÃÃÃÃÃÃÃÃÃÃÃ,661 D-uppsats Title of series, numbering ___________________________________ _ ________________ Övrig rapport _ ________________ 85/I|UHOHNWURQLVNYHUVLRQ www.ep.liu.se/exjobb/itn/2001/ed/005/ 7LWHO Microstrip Solutions for Innovative Microwave Feed Systems Title )|UIDWWDUH Magnus Petersson Author 6DPPDQIDWWQLQJ Abstract This report is introduced with a presentation of fundamental electromagnetic theories, which have helped a lot in the achievement of methods for calculation and design of microstrip transmission lines and circulators. The used software for the work is also based on these theories. General considerations when designing microstrip solutions, such as different types of transmission lines and circulators, are then presented. Especially the design steps for microstrip lines, which have been used in this project, are described. Discontinuities, like bends of microstrip lines, are treated and simulated. -
EMC Fundamentals
ITU Training on Conformance and Interoperability for ARB Region CERT, 2-6 April 2013, EMC fundamentals Presented by: Karim Loukil & Kaïs Siala [email protected] [email protected] 1 Basics of electromagnetics 2 Electromagnetic waves A wave is a moving vibration λ Antenna V λ (m) = c(m/s) / F(Hz) 3 Definitions • The wavelength is the distance traveled by a wave in an oscillation cycle • Frequency is measured by the number of cycles per second and the unit is Hz . One cycle per second is one Hertz. 4 Electromagnetic waves (2) • An electromagnetic wave consists of: an electric field E (produced by the force of electric charges) a magnetic field H (produced by the movement of electric charges) • The fields E and H are orthogonal and are m oving at the speed of light 8 c = 3. 10 m/s 5 Electromagnetic waves (3) 6 E and H fields Electric field The field amplitude is l expressed in (V/m). E(V/m) Magnetic field The field amplitude is expressed in (A/m). d H(A /m) Power density Radiated power is perpendicular to a surface, divided by the area of the surface. The power density is expressed as S (W / m²), or (mW /cm ²) , or (µW / cm ²). 7 E and H fields • Near a whip, the dominant field is the E field. The impedance in this area is Zc > 377 ohms. • Near a loop, the dominant field is the H field. The impedance in this area is Z c <377 ohms. 8 Plane wave 9 The EMC way of thinking Electrical domain Electromagnetic domain Voltage V (Volt) Electric Field E (V/m) Current I (Amp) Magnetic field H (A/m) Impedance Z (Ohm) Characteristic