# Chapter 1 Introduction: Waves and Phasors

# Chapter Contents

1. Overview

2. 1.1 Historical Timeline

3. 1.2 Dimensions, Units, and Notation

4. 1.3 The Nature of Electromagnetism

5. TB 1 LED Lighting

6. 1.4 Traveling Waves

7. 1.5 The Electromagnetic Spectrum

8. 1.6 Review of Complex Numbers

9. TB 2 Solar Cells

10. 1.7 Review of Phasors

1. Chapter 1 Summary

2. Problems

# Objectives

Upon learning the material presented in this chapter, you should be able to:

1. Describe the basic properties of electric and magnetic forces.

2. Ascribe mathematical formulations to sinusoidal waves traveling in both lossless and lossy media.

3. Apply complex algebra in rectangular and polar forms.

4. Apply the phasor-domain technique to analyze circuits driven by sinusoidal sources.

# Overview

Liquid crystal displays (LCDs) have become integral parts of many electronic consumer products, ranging from alarm clocks and cell phones to laptop computers and television systems. LCD technology relies on special electrical and optical properties of a class of materials known as liquid crystals, which are neither pure solids nor pure liquids but rather a hybrid of both. The molecular structure of these materials is such that when light travels through them, the polarization of the emerging light depends on whether or not a voltage exists across the material. Consequently, when no voltage is applied, the exit surface appears bright. Conversely, when a voltage of a certain level is applied across the LCD material, no light passes through it, resulting in a dark pixel. In-between voltages translate into a range of grey levels. By controlling the voltages across individual pixels in a two-dimensional array, a complete image can be displayed (Fig. 1-1). Color displays are composed of three subpixels with red, green, and blue filters.

# Figure 1-1 2-D LCD array.

Figure 1 1 Full Alternative Text

The subject of this book is applied electromagnetics (EM), which encompasses the study of both static and dynamic electric and magnetic phenomena and their engineering applications. Primary emphasis is placed on the fundamental properties of dynamic (time-varying) electromagnetic fields because of their greater relevance to practical applications, including wireless and optical communications, radar, bioelectromagnetics, and high-speed microelectronics. We study wave propagation in guided media, such as coaxial transmission lines, optical fibers, and waveguides; wave reflection and transmission at interfaces between dissimilar media; radiation by antennas, and several other related topics. The concluding chapter is intended to illustrate a few aspects of applied EM through an examination of design considerations associated with the use and operation of radar sensors and satellite communication systems.

We begin this chapter with a chronology of the history of electricity and magnetism. Next, we introduce the fundamental electric and magnetic field quantities of electromagnetics, as well as their relationships to each other and to the electric charges and currents that generate them. These relationships constitute the underpinnings of the study of electromagnetic phenomena. Then, in preparation for the material presented in Chapter 2, we provide short reviews of three topics: traveling waves, complex numbers, and phasors, which are all useful in solving time-harmonic problems.