This book presents ultrawideband antennas and their applications in microwave imaging. The chapters focus on recent techniques, analysis, and applications along with a future vision of this emerging field of applied electromagnetics. The primary emphasis on fundamental concepts, techniques, and practical applications equip readers of different knowledge levels with a new paradigm to understand this advanced field of engineering. This resource incorporates modern design concepts, analysis, and optimization techniques based on recent developments. Several emerging topics are essayed, including dielectric resonator antennas and planar ultrawideband antennas for microwave imaging. Readers are also provided with an extensive overview of current regulations, Including those related to microwave effects in biological tissues.