Electronic Beam Steering And Polarization Agile Planar Antennas In Liquid Crystal Technology

This book describes the characterization of liquid crystal materials at microwave frequencies and the usage of these materials in reconfigurable planar antennas and in their electrical tunable components. It reports for the first time the realization of a two-dimensional electronic beam steering antenna and polarization agile planar antennas with liquid crystal display technology. It gives a detailed description of all the theoretical analyses, modeling and design methods that were involved in the realization of these devices as well as their validation using measurement of demonstrative prototypes. This book also shows that low profile, low cost, high gain, electronic beam steering and polarization agile antennas can be fabricated in larger sizes by using existing automated liquid crystal display manufacturing techniques. The innovative ideas and method described in this work represent a considerable advancement in the field of electronically reconfigurable antennas based on liquid crystal technology and are expected to draw significant interest in the future. Such antennas may become important, for example, in mobile terminals integrated into the body of laptops (in the cover) or of automobiles (in the rooftop), ships or boats, for which flat, low-profile and low-cost antennas are required.

Describes the theory, modeling, and design of tunable mm-wave circuits and systems using CMOS, RF MEMS, and microwave liquid crystals.

This book presents original findings on tunable microwave metamaterial structures, and describes the theoretical and practical issues involved in the design of metamaterial devices. Special emphasis is given to tunable elements and their advantages in terms of feeding network simplification. Different biasing schemes and feeding network topologies are presented, together with extensive prototype measurements and simulations. The book describes a novel, unique solution for beam steering and beam forming applications, and thus paves the way for the diffusion of new agile communication system components. At the same time, it provides readers with an outstanding and timely review of wave propagation in periodic structures, tunability of metamaterials and the technological constraints that need to be considered in the design of reconfigurable microwave components.

A concise introduction to a complex field, bringing together recent work in cognitive science and cognitive robotics to offer a solid grounding on key issues. This book offers a concise and accessible introduction to the emerging field of artificial cognitive systems. Cognition, both natural and artificial, is about anticipating the need for action and developing the capacity to predict the outcome of those actions. Drawing on artificial intelligence, developmental psychology, and cognitive neuroscience, the field of artificial cognitive systems has as its ultimate goal the creation of computer-based systems that can interact with humans and serve society in a variety of ways. This primer brings together recent work in cognitive science and cognitive robotics to offer readers a solid grounding on key issues. The book first develops a working definition of cognitive systems—broad enough to encompass multiple views of the subject and deep enough to help in the formulation of theories and models. It surveys the cognitivist, emergent, and hybrid paradigms of cognitive science and discusses cognitive architectures derived from them. It then turns to the key issues, with chapters devoted to autonomy, embodiment, learning and development, memory and prospection, knowledge and representation, and social cognition. Ideas are introduced in an intuitive, natural order, with an emphasis on the relationships among ideas and building to an overview of the field. The main text is straightforward and succinct; sidenotes drill deeper on specific topics and provide contextual links to further reading.

Describes the configuration and principles of a reflectarray antenna, its advantages over other antennas, the history of its development, analysis techniques, practical design procedures, bandwidth issues and wideband techniques, as well as applications and recent developments. Both authors are well respected practitioners who have build these antennas and developed them for space flight.