Passive Microwave Device Applications of High Temperature Superconductors

M.J. Lancaster
Cambridge University Press
340 pages; $79.95

This book stems from laboratory work performed on high temperature superconducting (HTS) materials and the microwave aspects of these materials. In less than 10 years, superconducting communication and signal processing systems are being flown in space and many other microwave devices and systems are appearing in the marketplace. This book describes this development from the basic fundamentals of superconductors in high frequency fields to the use of superconductors in microwave passive applications.

The first chapter deals with the fundamental aspects of how superconductors interact with high frequency fields and discusses the theoretical tools available for solving related problems. Chapter 2 introduces superconducting transmission lines and discusses transmission properties under these conditions. A wide microstrip is studied that provides much insight into the use of superconductors. Chapter 3 describes HTS cavity resonators and explains how superconducting lowers conduction loss and reduces cavity current decay to a minimum.

Chapter 4 deals with microwave measurements and measuring equipment. Chapter 5 describes superconducting microwave filters and their advantages. The effects HTS has had on filter miniaturization and overall performance are described. HTS delay lines are covered in Chapter 6 with specific focus on how they perform as filters and signal processors. Superconducting antennas and feed networks are described in Chapter 7.

Areas in which superconducting techniques provide the greatest improvements in radiation efficiency and directivity are also described. Chapter 8 explains the use of superconducting techniques in complex signal processing and how a number of these functions can be integrated into one cold system. The appendices describe the surface impedance of HTS materials and substrates for superconductors.

This book provides a good basic introduction to HTS techniques and materials as they relate to high frequency operation. It is easy to read and understand, focusing mainly on applications rather than theory.

To order this book, contact: Cambridge University Press, 40 West 20th Street, New York, NY 10011-4211 (800) 872-7423.

Digital Beamforming in Wireless Communications

John Litva and Titus Kwok-Yeung Lo
Artech House Inc.
301 pages; $69, £55

Digital beamforming (DBF) was applied originally to sonar and radar systems. However, its real use will be in wireless communications, specifically in personal communications services.

This book introduces DBF and its upcoming applications in wireless and satellite communications. It is intended as a tutorial and reference book for communications engineers and technicians involved in the design and development of wireless communications systems, as well as for those who are interested in DBF techniques.

The book comprises three sections, the first of which presents the concepts and principles of DBF. Chapter 1 provides a background of DBF and rationalizes its use in wireless communications. The fundamentals of DBF are outlined in Chapter 2, and Chapter 3 presents the basics of adaptive beamforming. Chapter 4 concludes the first section with an examination of the effects of errors on DBF.

The second section covers the applications of DBF in wireless communications. Chapter 5 introduces the concept of spatial processing, including space-division multiple access. Chapter 6 describes DBF network configurations. The applications of DBF in satellite mobile communications, land mobile communications, and indoor and data communications are described in Chapters 7, 8 and 9, respectively. The final section reviews the state-of-the-art technologies required to support DBF, including antenna elements, transceiver technology and digital signal processing technology.

Techniques such as DBF offer the ability to exploit spatial-domain processing for communications system performance improvements similar to the recent optimization that took place using time-domain techniques. This book presents DBF theory, techniques and practical applications in a clear and straightforward manner, understandable easily by anyone with a basic knowledge of communications.

To order this book, contact: Artech House Inc., 685 Canton St., Norwood, MA 02062 (617) 769-9750, ext. 4002; or Portland House, Stag Place, London SW1E 5XA, UK +44 (0)171 973 8077.