Superconducting Fault Current Limiter

Abstract

Today, wireless communication is most commonly made possible through radio frequency (RF) waves propagating through air. However, applications such as underwater, underground, or medical communication, RF communication is not effective or possible due to the rapid attenuation of RF waves. For example, acoustic signals can travel over 1 km in water with little signal loss while RF waves will be attenuated in a very short distance. Magnetic induction has been used to provide wireless high-speed communications for underwater applications at propagation speeds of 3 x107 m/s with data rates of Mb/s and transmission distances of >50 m. This book introduces acoustic and magnetic communication from an engineering design perspective. It is divided into two parts – magnetic communications and acoustic communications. The magnetics topics cover wireless data and energy transfer and magnetic communications models. Wireless charging of cell phones and electric vehicle charging principles are described along with data-sharing applications. Efficiency between induction coils and upper bounds on high-speed data communications between induction coils are also detailed. Communications for underwater and mining applications using acoustic transmission methods detail network routing protocols, hybrid RF and acoustic transmission and propagation models. Since acoustic links have a much longer propagation delay time as compared to over air RF signals, conventional media access control (MAC) cannot be used. A new MAC schedule-based collision avoidance method is explained. Hybrid systems, using acoustic transmission for underwater and RF communication for above the water surface, are described in detail. These systems have complex network bandwidth management challenges and protocol controls that are also covered in detail. The propagation mathematical models describe the acoustic signal fading characteristics in free space and water. This book can provide research engineers who design underwater and underground communication systems with the latest insights and knowledge into nonRF networking schemes for improving existing products. With the latest technology and emerging topics discussed, electrical engineering communications students could also use this book for exploring ideas for research topics in this area or to just learn about the fundamentals of magnetic induction and acoustic communications.