Non-foster elements : new path towards broadband enz and mnz metamaterials

recently introduced at University of Zagreb, is reviewed. Several state-of-the art examples of extremely broadband (bandwidth of more than two octaves) 1D and 2D active ENZ metamaterials are presented together with possible applications. Some new research directions, which include broadband negative-inductance-based MNZ metamaterial and frequency independent transmission line, are stressed.