antenna basics

Antenna_BasicsANTENNA BASICS

Christof Rohner

Antenna Basics 2

CONTENTS

1 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 3 3.1 3.2 3.3 3.4 4 5

Introduction Antenna Characteristics Radiation Pattern Directivity Factor Gain Effective Area Effective Antenna Length Antenna Factor Impedances and Resistances Basic Characteristics of Selected Antennas Dipole Antennas Rod Antennas Directional Antennas Active Antennas Most Important Antenna Characteristics at a Glance Used and Recommended References

3 4 4 5 5 6 7 8 10 12 12 16 18 23 26 27

Basics_e.doc

Ro November 1999

Antenna Basics 3 1 Introduction

Antennas are used for converting conducted electromagnetic waves into electromagnetic waves freely propagating in space and vice versa (Fig. 1.1). The name is derived from the field of zoology, where the term antennae (Lat