RF and Microwave Wireless Systems

CHAPTER ONE

Introduction

1.1   BRIEF HISTORY OF RF AND MICROWAVE WIRELESS SYSTEMS

The wireless era was started by two European scientists, James Clerk Maxwell and Heinrich Rudolf Hertz. In 1864, Maxwell presented Maxwell’s equations by unifying the works of Lorentz, Faraday, Ampere, and Gauss. He predicted the propagation of electromagnetic waves in free space at the speed of light. He postulated that light was an electromagnetic phenomenon of a particular wavelength and predicted that radiation would occur at other wavelengths as well. His theory was not well accepted until 20 years later, after Hertz validated the electromagnetic wave (wireless) propagation. Hertz demonstrated radio frequency (RF) generation, propagation, and reception in the laboratory. His radio system experiment consisted of an end-loaded dipole transmitter and a resonant square-loop antenna receiver operating at a wavelength of 4 m. For this work, Hertz is known as the father of radio, and frequency is described in units of hertz (Hz).

Hertz’s work remained a laboratory curiosity for almost two decades, until a young Italian, Guglielmo Marconi, envisioned a method for transmitting and receiving information. Marconi commercialized the use of electromagnetic wave propagation for wireless communications and allowed the transfer of information from one continent to another without a physical connection. The telegraph became the means of fast communications. Distress signals from the S.S. Titanic made a great ...