Planar microwave lens based on complementary metamaterials

In the past few years, the complementary metamaterials have been used in the design of microwave devices like filters and patch antennas. The complementary metamaterials are usually composed of two-dimensional waveguided units. They can also exhibit electric or magnetic responses under the excitation of dominant TEM mode in the planar waveguide, which can be directly inferred from the Babinet´s theory. In this paper, some kinds of microwave lens developed recently based on complementary metamaterials have been reviewed, which may be utilized in the microwave devices or experiments.