Babinet's principle is applied to three kinds of metamaterial designs, including SRR structure, S structure, and single side paired S-ring. The retrieval results for each complementary unit cell group are obtained based on their S11 and S21 simulation data. By means of comparison, the complementary metamaterial's negative permittivity happens at the same frequency band, where is supposed to be a ... [Show full abstract] magnetic resonance for the original metamaterial structure; And on the other side, the effective permeability of complementary metamaterial acts in a similar way which is corresponding to the effective permittivity of the prototypes. The results show that the Babinet's principle is useful and helpful while designing metamaterials. After proper design, some complementary metamaterials' structures can also possess both electric resonances and magnetic resonances at the same time, which conform to the condition for left-handed metamaterials.