This book focuses on the understanding of the Cylindrical Dielectric Resonator Antennas (CDRA). The book introduces the fundamentals of DRA, CDRA, identifying the modes in a CDRA, excitation techniques and recent advancements pertaining to the research of the CDRAs. The latest trends in the field are discussed, including wide bandwidth of operation, high gain, modal stability, mode and impedance matching techniques, Circularly Polarized CDRAs, beam forming and MIMO applications for modern wireless systems. The experimental validation, testing, fabrication methods and machining to achieve cylindrical and its reformed shapes are also presented.