Measurement of Mobile Antenna Systems

Abstract

Why do we need a monograph on measurement of mobile antenna systems? There are two reasons. Firstly, despite the problems that the mobile communications industry are currently having as a result of uncertainties of third generation system uptake, it remains one of the most important technology sectors across the world. Secondly, whilst the topic of antenna measurement techniques is a largely mature one, there are significant new challenges thrown up in measuring antennas on mobile terminals. Most antennas used in fixed systems are intended to operate in a single direction. They are thus measured in an anechoic, or reflectionless, chamber or on a special outdoor range that ensures incident energy arrives from a single direction only. When operating a mobile telephone in a built-up area, possibly without a line of sight, a multipath propagation environment occurs with rays from the base station incident from many directions simultaneously. The measurement of the antenna must in some way simulate this environment. The close proximity of the head is a further factor that leads to novel and unique measurement problems both in terms of the characterization of the radiation properties and the measurement of the absorption of energy into body tissues. For these reasons this book is both welcome and timely. The book aims to cover, in a comprehensive way, antenna measurement methods for both mobile and base station antennas. To some degree these two topics sit uneasily together. The techniques for the mobile antenna are very different from those for the base station. Mobile antennas are usually small low-gain types and need the new methods noted above. Base station antennas, on the other hand, require conventional, although nonetheless demanding, measurement methods and these have been well described elsewhere. Having said that, the book does form a comprehensive introduction to measurement of all types of mobile system antennas and is thus an excellent reference and primer for workers new to the field. The chapters on measurement of mobile antennas form the meat of the book and do justice to what is both a difficult problem for antenna designers and manufacturers yet also a fascinating and challenging area for researchers. For example, the use of dielectric phantoms as physical representations of the head and hand is now an acknowledged method to allow the body effect on the antenna radiation properties and the specific absorption rate to be measured. It is well covered. Fading and incident field simulators are also extensively dealt with. Here, the creation of a multipath environment within a metallic enclosure by the use of multiple sources is a demanding and fascinating new development in antenna measurements and the book presents some of the latest results using this method. Measurement of Mobile Antenna Systems is a book that will be of interest to engineers, both those who are experienced in antenna measurements and those who are just entering the field of mobile antenna design and measurement. It is also sufficiently novel to appeal to researchers looking for new challenges. It is most heartily recommended. P Hall