Preface

Since the inception of wireless systems, engineers have continuously strived to develop systems that utilize higher frequencies, in pursuit of numerous advantages that it may offer to particular applications. As a result, the components that constitute a typical wireless system—that is, the antenna and the analog and digital front ends—have been fiercely studied and remarkable developments have surfaced in the last century. While millimeter-wave systems are relatively new (only experiencing any real development since the 70s), they are arguably one of the fastest growing fields in wireless research. Rapidly developing standards and component technology have two major driving forces behind the tremendous growth that we have come to witness in the past decade. For researchers and designers entering this field, the vast extent of information, research results and systems that exist can be gruesomely overwhelming, which is where this text is intended to assist. This text is heavily focused on current research, and it is designed to cover as many different antenna configurations and applications as possible. It should therefore enable a designer (or researcher, for that matter) to make an informed decision on one of the most critical components of a wireless system. As the text progresses, the reader will notice that special attention is paid to measurement techniques and practical results. While fundamental concepts form the baseline of each system that we intend to discuss, there are a multitude of other books that intensely cover relevant theory. Nonetheless, where it is deemed applicable, this text does attempt to cover fundamental theory, but it is assumed that the reader has sound understanding of wireless systems and antenna concepts. Discussions in the introductory chapter are intended to provide an idea of development trends witnessed in millimeter-wave systems, and stretches from the earliest stage of the field up until modern times, leaving the reader ready to expand into the next six chapters. A second key part of the introductory chapter is a discussion on spectrum management and allocation, which is the first and perhaps the most crucial component necessary to develop any wireless system. Following this, there is no prescribed order in which the next five chapters should be