Fast and efficient algorithms in computational electromagnetics [Book Review]

An engineer or scientist working in the topical area of propagating electromagnetic fields has typically three alternatives to evaluate his or her brilliant ideas. First, if this individual is very talented and of theoretical character, he or she can, of course, take pen and paper and figure it all out from Maxwell’s equations through the world of tensors and anistropic media. However, we have not really seen many of this type in the neighborhood, although this reviewer daily sits in the premises of a distinguished technical university where theory is supposed to live and flourish. The next alternative is to find the workshop and take some very practical tools in order to create a real physical model of the invention. This could be a new handset antenna, a complicated microstrip board for millimeter wave work or a full aircraft carrier in scale size hopefully for Radar Cross Section (RCS) measurements. If starting from scratch, the process can be time-consuming and does not generally provide much freedom for adjustments without considerable re-working, but is considered quite reliable. The third choice is computer simulations. It lays somewhere between real prototyping and pure theory and it is possible for the humble scientist (after only the recently introduced powerful desk-top computers). Simulation models and methods are as numerous as their inventors and opinions about their suitability for different tasks have not always seen a rigorous convergence. Still, they are here to stay and we should try and make the most of them with the best reliability at hand. Artech House has very recently published a new book entitled Fast and Eflcient Algorithms in Computational Electromagnetics. It is edited by four experienced scientists, namely Professor Weng Cho Chew, Professor Jing-Min Jin, Associate Professor Eric Michielssen and Jiming Song. Actually, the total number of contributing authors is twenty-two, of which twenty are currently affiliated to or have been working in recent years at the University of Illinois (Urbana-Champaign). We decided to give our readers a glimpse of their work in the field of electromagnetic computer simulations. The first impression of this book can be something similar to that reported in the classic The Longest Day (Cornelius Ryan, 1959) where the German Major Wemher Pluskat looks at the Allied invasion fleet through his periscope somewhere on the beaches of Normandy in the early hours of D-day. Already, the plain statistics of Fast and Eflcient Algorithms in Computational Electromagnetics makes a less experienced man-from-the-lab very exhausted. We have a 93 1 -page monster with nineteen chapters, a separate index, and many references. In fact, the alphabetical index contains over 2900 separate words or word combinations and the total number of bibliographical references is 950 or so. To continue playing with numbers, the book uses at least 1914 equations and mathematical formulas and has no less than 370 illustrations. This should be enough by any standard. After the conventional introduction, the next four chapters discuss various aspects of the Multilevel Fast Multipole Algorithm in twoand three-dimensional environments. Chapters 3 and 4, despite their theoretical nature, use selected RCS estimations as examples of presented methods and highlight details of platform performance requirements, too. Interesting topics include Chapter 8, which illustrates some means of computing electromagnetics related to the detection of buried objects, Chapter 10, where waveguide discontinuities are analyzed and Chapter 1 1, which shows some new ways for numerical simulation of indoor propagation of radio waves. Chapter 12 deals with the Finite-Element Analysis and describes the algorithmic basis for fast RCS computation of special artillery ammunition or air-to-air or air-to-surface missiles. Then, Chapter 13 is about hybridization methods whereby relatively large objects having small details can be efficiently handled. The RCS example is the VFY2 18 fighter aircraft. Other nice topics in this book are broadband calculations in Chapter 15 and full-wave analysis of multilayer microstrips in Chapter 16. Here, typical applications include cavity-backed microstrip antennas and various filters or hybrid couplers. The two last chapters discuss some important issues of time-domain algorithms and their effectiveness.