This book presents ultrawideband antennas and their applications on microwave imaging. The chapters focus on recent techniques, analysis, and applications along with the future vision of this emerging field of applied electromagnetics. Several emerging topics are essayed, including dielectric resonator antennas and planar ultrawideband antennas for microwave imaging. This resource incorporates modern design concepts, analysis, and optimization techniques based on recent developments. Readers are also provided with an extensive overview of current regulations, including those related to microwave effects in biological tissues.