Preface
The word radio means techniques that are used in transmitting and receiving information or power in the atmosphere or free space, or in transmission lines utilizing electromagnetic waves—so-called radio waves—but also the equipment needed therein.
This book provides the reader with the basics in radio engineering, the techniques needed to generate, control, detect, and use radio waves. The text approaches the relevant problems both from the electromagnetic theory based on Maxwell’s equations and from the circuit theory based on Kirchoff and Ohm’s laws. Brief introductions to the electromagnetic theory as well as to the circuit theory are provided. Besides passive transmission lines and components, active RF circuits are also addressed. The treatment of the fundamentals of antennas and radio wave propagation in this book leads the reader to radio systems with noise and modulation considerations. Finally, a broad range of applications are described in addition to various wireless communication applications: radionavigation, radar, radiometry, remote sensing, radio astronomy, RF sensors, power and medical applications, and electronic warfare. The book ends with a short review of biological effects and safety standards. While numerous books specializing in various topics of radio engineering are available, this book gives a well-balanced, general overview of the whole topic. To the authors’ knowledge, there are no similar books available.
This book got its origin from course lectures on the same topic at the Helsinki University of Technology. When we found that the Finnish text of our book (which was first published in 1992) written for our students
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became very popular in the well-known Finnish wireless industry, we decided to write a similar book in English in order to provide an overview of this important technology to engineers, managers, sales representatives, and administrators globally.
In order to take full advantage from the contents of this book, one needs a solid background in physics and mathematics. The text can be used also without this background to obtain a general understanding of radio engineering, especially in Chapters 1, 12, and 13, and partly in Chapters 9, 10, and 11.
Acknowledgments
We authors would like to thank our many colleagues and students, former and current, at the Helsinki University of Technology for their encouragement and many useful comments. We especially want to mention the help of Professors Sergei Tretyakov, Pertti Vainikainen, and Pekka Eskelinen. We would also like to express our appreciation of the professional drawings made by Harri Frestadius.
Dr. Ra¨isa¨nen is grateful to the Observatoire de Paris (LERMA) and Universite´ de Paris 6, and especially to Professor Pierre Encrenaz for providing excellent conditions and good atmosphere for this writing task during his sabbatical leave.
Finally, we would like to thank our family members for their very important emotional support during the writing of this book.
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