The Art and Science of Ultrawideband Antennas (Artech House Antennas and Electromagnetics Analysis Library)

This comprehensive treatment of ultrawideband (UWB) antennas and time-domain microwave engineering serves as an invaluable practical reference for anyone involved in antenna and RF design work. This authoritative volume enables readers to select the proper UWB antennas for their applications, design and analyze UWB antennas, and integrate these antennas in an RF system. By applying time-domain thinking to problems of practical interest, the reader will not only learn how to build and analyze antennas, but also understand them at the most fundamental level. This second edition is updated and expanded throughout, providing readers with a history of antennas, numerous new problem sets and worked examples, along with new information on plotting time-domain field lines, time-domain reflectometry, matching techniques, and more. This book also addresses system issues like spectral control and antenna efficiency. Machine generated contents note: 1.1.Antennas and Elephants 1.2.Three Centuries of UWB Antennas 1.3.What Is an Antenna? 1.3.1.Antennas as Transducers 1.3.2.Antennas as Transformers 1.3.3.Antennas as Radiators 1.3.4.Antennas as Energy Converters 1.4.UWB Antennas 1.4.1.A Taxonomy of UWB Antennas 1.4.2.UWB Device and Systems Considerations 1.5.Conclusion Endnotes 2.1.Nineteenth-Century UWB Antennas 2.1.1.Heinrich Hertz 2.1.2.Narrowband in Conception, UWB in Practice 2.1.3.Jagadis Chandra Bose 2.1.4.Oliver Lodge 2.1.5.Guglielmo Marconi 2.2.Twentieth-Century UWB Antennas 2.2.1.Rediscovery of the Biconical Antenna 2.2.2.Bulbous UWB Elements 2.2.3.Rediscovery of the Horn Antenna 2.2.4.Toward More Manufacturable Designs 2.2.5.Frequency-Independent Antennas 2.2.6.Origins of Ultrawideband Radio Technology 2.3.Twenty-First-Century UWB Antennas 2.3.1.Planar Monopole Antennas 2.3.2.Planar Dipole Antennas 2.3.3.Magnetic Antennas 2.3.4.Frequency-Notched UWB Antennas 2.3.5.Other Recent Advances 2.3.6.Progress in UWB Commercialization 2.4.UWB Antennas: What's Ahead? 2.5.Conclusions Problems Endnotes 3.1.Bandwidth 3.1.1.Calculating Bandwidth 3.1.2.Determining Antenna Bandwidth 3.1.3.Radiated Bandwidth 3.2.Dispersion 3.2.1.Example of a Dispersive Antenna 3.2.2.Example of a Nondispersive Antenna 3.2.3.Angular Dependence of Dispersion 3.3.Where Energy Goes 3.3.1.Antenna Pattern 3.3.2.Antenna Directivity, Gain, and Bandwidth 3.4.Pattern, Gain, and UWB Antennas 3.4.1.Reciprocity and UWB Antennas 3.4.2.Constant Gain Antennas 3.4.3.Constant Aperture Antennas 3.4.4.Other UWB Antennas 3.4.5.Gain and Aperture 3.5.Polarization 3.6.Antenna Matching 3.7.Antennas as Transducers Problems Endnotes 4.1.Introduction to Antenna Impedance 4.1.1.UWB Versus Narrowband Antenna Impedance 4.1.2.Controlling Antenna Impedance 4.2.Transmission Lines 4.2.1.Early Developments 4.2.2.Twin-Lead Transmission Line 4.2.3.Coaxial Transmission Line 4.2.4.Parallel Plane Transmission Line 4.2.5.Microstrip Line 4.3.Transition from Feed Line to Free Space 4.3.1.Twin-Lead Transition 4.3.2.Coaxial Transitions 4.3.3.Planar Transmission Line Transitions 4.4.Impedance Transformation and Matching 4.4.1.The Terminated, Lossless Line 4.4.2.Time-Domain Reflectometry 4.4.3.Harmonic Signals 4.4.4.The Smith Chart and Matching Networks 4.4.5.Broadband Matching 4.5.Coupling Balanced and Unbalanced Lines 4.5.1.Chokes 4.5.2.Balun Transformers 4.5.3.Compatibility 4.6.Antennas as Transformers Problems Endnotes 5.1.Time Domain and Frequency Domain 5.1.1.Impulses and Sine Waves 5.1.2.Basic Principles of the Frequency and Time Domain 5.1.3.Time-Domain Signals 5.1.4.Time Domain Versus Frequency Domain 5.2.Maxwell's Equations 5.2.1.Generalized Coordinates and Retardation 5.2.2.Electromagnetic Waves 5.2.3.Jefimenko Form of the Biot-Savart and Coulomb Laws 5.2.4.Right-Hand Rule for Radiation 5.2.5.Time-Domain Representation of Plane Waves 5.3.Linear Antennas 5.3.1.Linear Antenna Behavior 5.3.2.Examples 5.3.3.Summary 5.4.Dipole Fields 5.4.1.Electric Dipole Fields 5.4.2.Magnetic Dipole Fields 5.4.3.Harmonic Dipole Fields 5.4.4.Exponentially Decaying Dipole Fields 5.5.Basic Antenna Physics 5.5.1.Antenna Differentiation 5.5.2.The Radiation Field Approximation 5.5.3.Radiation of a DC Signal? 5.5.4.Field Lines 5.6.Antennas as Radiators Problems Endnotes 6.1.Motivation 6.1.1.Models and Reality 6.1.2.Is Radiation "Kinky"? 6.1.3.The Maxwellian Perspective 6.2.Localization and Flow of Electromagnetic Energy 6.2.1.Localizing Electromagnetic Energy 6.2.2.The Flow of Electromagnetic Energy 6.2.3.Puzzles and Paradoxes of Electromagnetic Energy Flow 6.2.4.Electromagnetic Velocity 6.2.5.Causal Surfaces 6.3.Electromagnetic Energy in Simple Problems 6.3.1.Energy in Superposition 6.3.2.Energy in Standing Waves 6.4.Dipole Field Energy 6.4.1.Exponentially Decaying Dipoles 6.4.2.Damped Harmonic Dipoles 6.4.3.Harmonic Dipoles 6.4.4.Time-Domain Excitations 6.5.Optimal Element Design 6.5.1.Fatter Is Better 6.5.2.Optimal Dipole Shape 6.5.3.Optimal Loop Shape 6.6.Fundamental Limits on Antenna Size 6.6.1.The Chu-Harrington Limit 6.6.2.The McLean Derivation of Small Antenna Q 6.6.3.Is There a Q in UWB? 6.6.4.Q-Based Antenna Limits in UWB Practice 6.6.5.Energy-Flow-Based Limits to Antenna Performance 6.7.Antennas as Energy Converters Problems Endnotes 7.1.Frequency-Independent Antennas 7.1.1.Basic Principles of Frequency-Independent Antennas 7.1.2.Spiral Antennas 7.1.3.Log-Periodic Antennas 7.1.4.Fractal and Bent Wire Antennas 7.2.Small-Element Electric Antennas 7.2.1.Conical Antennas 7.2.2.Planar Conical Antennas 7.2.3.Bulbous Antennas 7.2.4.Planar Bulbous Antennas 7.2.5.Other Planar Monopole UWB Antennas 7.2.6.Physical Behavior of Planar UWB Antennas 7.2.7.General Principles of Small-Element Design 7.2.8.Summary of Small-Element Electric Antennas 7.3.Small-Element Magnetic Antennas 7.3.1.Complementarity 7.3.2.UWB Slot Antennas 7.3.3.Large Current Radiator Antennas 7.3.4.Monoloop Antennas 7.3.5.Loop Antennas 7.3.6.Summary of Small-Element Magnetic Antennas 7.4.Electrically Small Antennas 7.4.1.Antenna Scaling 7.4.2.Dielectric Loading 7.4.3.Conducting Enclosure Antennas 7.4.4.Electric-Magnetic Antenna 7.4.5.Summary of Electrically-Small antennas 7.5.Directional Electrically Small Antennas 7.5.1.The Beverage Loop 7.5.2.Ewes, Flags, and K9AYs 7.5.3.Multipole Synthesis 7.5.4.Performance of Multipole Designs 7.5.5.Experimental Results 7.6.Horn Antennas 7.6.1.Conical Plate Horn Antenna 7.6.2.Termination of Horn Antennas 7.6.3.Planar Horn Antennas 7.6.4.Other Horn Antennas 7.6.5.Summary of Horn Antennas 7.7.Reflector Antennas 7.7.1.Planar Reflector 7.7.2.Corner Reflectors 7.7.3.Parabolic Cylinder Reflectors 7.7.4.Impulse Radiating Antennas 7.7.5.Summary of Reflector Antennas 7.8.Summary Problems Endnotes 8.1.Antenna Spectral Control 8.1.1.Antenna Scaling 8.1.2.Antenna Filtering 8.1.3.Antennas and Spectral Control 8.2.Antenna Efficiency 8.2.1.Efficiency Theory 8.2.2.Efficiency Measurement 8.3.Antenna Directivity 8.3.1.Omni Versus Directional 8.3.2.Amplitude Comparison Direction Finding 8.3.3.Small-Aperture UWB Direction Finding 8.3.4.Applications 8.3.5.Conclusion 8.4.UWB Antennas in Systems 8.5.Summary and Conclusions Problems Endnotes.