Electromagnetic Waves Interaction in Different Media

Chapter 4

Materials

Graham Brodie

Abstract

1. Introduction

time torsion [5].

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the wave (m); and

Energy Transfer from

transferred to materials by electromagnetic fields.

information acquisition, dielectric heating

Keywords: electromagnetic propagation, dielectric properties,

1. Frequency (f), which is given the unit of Hertz (Hz);

3. Speed (c), which is measured in metres per second.

These three properties are related by the equation:

Electromagnetic Fields to

Electromagnetic fields are complex phenomena, which transport energy and information across space. Information can be imposed onto electromagnetic waves by human ingenuity, through various forms of modulation; however, this chapter will focus on the acquisition of information as electromagnetic waves are generated by materials or pass through materials. The chapter will also consider how energy is

Electromagnetic fields are a complex phenomenon because they can propagate through vacuum without the need for a material medium, they simultaneously behave like waves and like particles [1, 2], and they are intrinsically linked to the behaviour of the space–time continuum [3]. It can be shown that magnetic fields appear through relativistic motion of electric fields, which is why electricity and magnetism are so closely linked [4]. It has even been suggested that electromagnetic phenomena may be a space–time phenomenon, with gravitation being the result of space–time curvature [3] and electro-magnetic behaviour being the result of space–

James Clerk Maxwell developed a theory to explain electromagnetic waves. He summarised this relationship between electricity and magnetism into what are now referred to as "Maxwell's Equations." An EM wave is described in terms of its:

2.Wavelength (λ), which is the distance between successive crests or troughs in

c ¼ λf (1)
