This book introduces the fundamental principles of antenna theory and explains how to apply them to the antennas' analysis, design, and measurements. Due to the variety of research and design methods and the different antenna structures available, the applications covered in this book are made to some of the most basic and practical antenna configurations. Among this antenna, configurations are linear dipoles, loops; arrays; broadband antennas; aperture antennas; horns, microstrip antennas, and reflector antennas. The text contains sufficient mathematical detail to enable undergraduate and beginning graduate students in electrical engineering and physics to follow the flow of analysis and design. Readers should have a basic knowledge of undergraduate electromagnetic theory, including Maxwell's equations and the wave equation, introductory physics, and differential and integral calculus.