In modern communication systems the demand for miniaturization and integration of multiple radio systems such as communication system, GPS receivers, 5G, wireless Internet devices operating at multiple frequencies are increasing. These systems using cognitive radio or flexible radio need smaller wideband antennas. The antennas based on metamaterial structures such as high permittivity periodic structures, mushroom, EBG, FSS, composite left/right-handed etc. are capable of greatly improving antenna performance. The use of metamaterials in antenna design not only significantly reduces the size of the antenna but also improve other antenna parameters such as increasing gain, enhancing bandwidth, or generating multiband frequencies of antennas operation. EBG structures which exhibit metamaterial behavior, are used intensively in the application of microstrip antennas. These structures are adopted to reduce surface waves and increase the gain of antennas and it was first introduced as frequency selective surfaces (FSS). This webinar will explain the latest research and development of metamaterials-based antenna technologies for ultra-wide band applications.