This is a professional level, introductory text on antenna principles, design, analysis, and measurements. It is especially suitable for persons who wish to improve their knowledge of antenna principles, concept design, performance analyses, and measurements. It is not a cookbook-like catalog for antenna design, nor does its understanding require a familiarity with electromagnetic theory, sophisticated mathematics, or complex computer techniques. The 3rd Edition updates and expands the original text by Lamont Blake, which was prepared at the undergraduate engineering, science, or technology level. For providing technical depth at the senior and graduate university levels, additions to the original book include a greatly expanded Chapter 7 on Antennas with Special Properties, a brand new Chapter 8 on Electronically Steered Arrays, and a revised Chapter 9 on Measurements. Also new to this edition are numerous appendices to the updated text and a CD-ROM with sample computer analyses. Reader knowledge assumes familiarity with basic college physics and mathematics. Computer computations use Mathcad(R) software, which can be read and used by persons without prior computer programming knowledge. The book is therefore suitable for entry-level as well as the more experienced professionals who desire to expand their understanding of and capabilities for antenna principles, analyses, measurements, and design.