The interface between radio waves that propagate through space and electric currents moving in metal conductors is termed as an antenna. It is used with a transmitter or receiver. In transmission process, electric current is supplied to the antenna's terminals through a radio transmitter, and the antenna radiates energy from the current in the form of electromagnetic waves or radio waves. During the process of reception, an antenna catches some of the power of a radio wave so that it can produce electric current at its terminals, which is conveyed to a receiver to be amplified. Some of the important characteristics of antennas are bandwidth, gain, radiation pattern efficiency and polarization. This book elucidates the concepts and innovative models around prospective developments with respect to antenna systems. It explores all the important aspects of antenna systems in the present day scenario. As this field is emerging at a rapid pace, the contents of this book will help the readers understand the modern concepts and applications of the subject.