[신간안내] Computational Electrodynamics (the finite difference time - domain method)

The main directions of studies of materials with negative index of refraction, also called left-handed or metamaterials, are reviewed. First, the physics of the phenomenon of negative refraction and the history of this scientific branch are outlined. Then recent results of studies of photonic crystals that exhibit negative refraction are discussed. In the third part numerical methods for the simulation of negative index material configurations and of metamaterials that exhibit negative index properties are presented. The advantages and the shortages of existing computer packages are analyzed. Finally, details of the fabrication of different kinds of metamaterials are given. This includes composite metamaterials, photonic crystals, and transmission line metamaterials for different wavelengths namely radio frequencies, microwaves, terahertz, infrared, and visible light. Furthermore, some examples of practical applications of metamaterials are presented.

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Negative Refractive Index Materials

A planar triangular monopole antenna (PTMA) is presented for high-frequency structure simulator ultra-wideband (UWB) communication. The high-frequency structure simulator three-dimensional electromagnetic solver is employed for design simulation. A printed PTMA has been realized by using the FR-4 printed circuit board substrate. The measured voltage standing wave ratio is less than 3 from 4 to 10 GHz. In the UWB communication frequency range, the measured phase distribution of the input impedance is quite linear and the H-plane patterns are almost omni-directional. The Kirchhoff's surface integral representation was adopted in the developed finite-difference time-domain code to compute the far field distributions from the near filed ones in time-domain. This is to investigate the radiated power density spectrum (PDS) shaping to comply with FCC emission limit mask. The effect of various source pulses (first-order Rayleigh pulses with /spl sigma/ of 20, 30, and 50 ps) on the radiated PDS shaping is also studied.

A planar triangular monopole antenna for UWB communication

This chapter is a starting point to look around and see where you’re going before you dig into details. The goal is to put fiber optics and communications into context and show how they go together. I start with a personal commentary about the turbulent times of the past several years, then explain the plan for this book. A brief history of fiber optics follows, which introduces some important concepts. Then a brief history of communications explains the need for bandwidth and how fiber optics filled that need, perhaps too well. Finally, I explain some of the terminology of the field to help you in your looking about.

An Introduction to Fiber Optics

We propose a novel numerical method to simulate transient electromagnetic problems. The time derivatives are still tackled with the customary explicit leapfrog time scheme. But in the space domain, the fields at the collocation points are expanded into a series of radial basis functions and are treated with a meshless method procedure. Our method solves numerically Maxwell's equations with various assigned boundary conditions and current source excitation. Furthermore, the numerical stability condition of our method is obtained through a one-dimensional (1-D) wave equation and thus the relationship between control parameters is accounted for. To verify the accuracy and effectiveness of the new formulation, we compare the results of the proposed method with those of the conventional finite-difference time-domain method through a 1-D case study with different boundary conditions.

Meshless Radial Basis Function Method for Transient Electromagnetic Computations

Artykul prezentuje wybrane metody, ktore są rozwijane w Politechnice Gdanskiej, i ktore mogą byc wykorzystane do przyspieszenia komputerowego projektowania ukladow mikrofalowych i analizy numerycznej ukladow niskiej i duzej czestotliwości. Przeprowadzono przegląd metod tworzenia ukladow zastepczych i ich wykorzystanie do automatycznego projektowania filtrow pasmowo-przepustowych. Przedstawiono rozne podejścia reprezentacji pola elektromagnetycznego bazujące na metodach siatkowych i bezsiatkowych i zilustrowano ich wydajnośc na przykladach o zlozonej geometrii.

Advances in computational electrodynamics.

A simple and flexible algorithm for finding zeros of a complex function is presented. An arbitrary-shaped search region can be considered and a very wide class of functions can be analyzed, including those containing singular points or even branch cuts. The proposed technique is based on sampling the function at nodes of a regular or a self-adaptive mesh and on the analysis of the function sign changes. As a result, a set of candidate points is created, where the signs of the real and imaginary parts of the function change simultaneously. To verify and refine the results, an iterative algorithm is applied. The validity of the presented technique is supported by the results obtained in numerical tests involving three different types of functions.

Complex Root Finding Algorithm Based on Delaunay Triangulation

On root finding algorithms for complex functions with branch cuts

A flexible and effective algorithm for complex roots and poles finding is presented. A wide class of analytic functions can be analyzed, and any arbitrarily shaped search region can be considered. The method is very simple and intuitive. It is based on sampling a function at the nodes of a regular mesh, and on the analysis of the function phase. As a result, a set of candidate regions is created and then the roots/poles are verified using a discretized Cauchy’s argument principle. The accuracy of the results can be improved by the application of a self-adaptive mesh. The effectiveness of the presented technique is supported by numerical tests involving different types of structures, where electromagnetic waves are guided and radiated. The results are verified, and the computational efficiency of the method is examined.

Global Complex Roots and Poles Finding Algorithm Based on Phase Analysis for Propagation and Radiation Problems

A flexible and effective algorithm for complex roots and poles finding is presented. A wide class of analytic functions can be analyzed, and any arbitrarily shaped search region can be considered. The method is very simple and intuitive. It is based on sampling a function at the nodes of a regular mesh, and on the analysis of the function phase. As a result, a set of candidate regions is created and then the roots/poles are verified using a discretized Cauchy's argument principle. The accuracy of the results can be improved by the application of a self-adaptive mesh. The effectiveness of the presented technique is supported by numerical tests involving different types of structures, where electromagnetic waves are guided and radiated. The results are verified, and the computational efficiency of the method is examined.

Piotr Kowalczyk

Papers

Advances in computational electrodynamics.

Complex Root Finding Algorithm Based on Delaunay Triangulation

On root finding algorithms for complex functions with branch cuts

Global Complex Roots and Poles Finding Algorithm Based on Phase Analysis for Propagation and Radiation Problems

Global Complex Roots and Poles Finding Algorithm Based on Phase Analysis for Propagation and Radiation Problems