Waves, either electromagnetic (EM) or acoustic (AC) interact with objects and scatter. The addition of incident and scattered fields form the total fields. Scattered fields include (but not limited with) reflections, refractions, and diffractions. The Handbook of Next Generation Emergency Services by is about diffraction modeling and simulation.
Scattering has gained much attention because of the increase of wireless communication in our environment. For example, recent iPhone devices deliver Gigabit-class long-term evolution for superfast download speeds. The next 5G wireless network technologies have served more devices and the number of antennas has increased to satisfy the connections therefore the behavior of electromagnetic propagation has to be considered in our life. Apart from that, the Internet of Things (IoT) has gained great significance in our daily life, and 23 billion IoT devices are expected to be used in the world by 2023. The sensors that operate with low power and need to send their data in limited time make up a vast majority among them and the success of transmission become crucial to ensure reliable operation. Hence, a proper understanding of electromagnetic propagation is required to set up indoor and outdoor low power wireless networks.
Scattering problems are complex therefore modeling and simulation have played a significant role to design new products before production. The solution strategies should be grouped as measurements, analytical modeling, and numerical simulations. Measurement is not easy to make in electromagnetics, in most cases, it is also time-consuming and expensive. On the other hand, there is a limited number of analytical solutions for highly idealized engineering problems therefore numerical simulations are mostly preferred for many real-life engineering electromagnetic problems.
The first chapter introduces some fundamental concepts of electromagnetic problems, identities, and definitions for diffraction modeling. Basic coordinate systems, Maxwell equations, boundary conditions, wave equation, Green’s function problem are given. The scattered fields, diffracted fields, and fringe fields, radar cross section for diffraction modeling are presented. The second chapter presents the behavior of electromagnetic waves around the two-dimensional canonical wedge. Chapter 3 presents the behavior of electromagnetic waves around the two-dimensional canonical strip. The behavior of electromagnetic waves around the two-dimensional canonical triangular cylinder is presented in Chapter 5. The diffraction of trilateral cylinders and wedges with rounded edges is investigated in Chapter 6. In Chapter 7, the double tip diffraction using Finite Difference Time Domain and Method of Moments is discussed. Chapter 8 presents a MatLab based virtual tool of diffraction from a perfectly reflecting wedge and Chapter 9 presents a MatLab based virtual tool, developed in Matlab with graphical user interface (GUI), for the visualization of both fringe currents and fringe waves. The last chapter presents a MatLab-based electromagnetic wedge diffraction virtual tool. The virtual tool uses numerical FDTD and MoM algorithm and High-Frequency Asymptotics approach.
This book is a continuation of the book “Fundamentals of the Physical Theory of Diffraction” written by Pyotr Ya Ufimtsev in 2014 and presents the application of diffraction with canonical structures using analytical and numerical methods. The powerful numerical methods are given with several scenarios.
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