The invention provides a middle and
far infrared broadband metamaterial absorber and a design method thereof. The middle and
far infrared broadband metamaterial absorber comprises
metamaterial absorption units which are arranged in a periodic array mode. The whole metamaterial absorption unit is square and comprises a top
metal layer, a
dielectric layer and a bottom
metal layer from top to bottom in sequence. The top
metal layer is attached to the upper surface of the
dielectric layer and is formed by arranging eight metal sheets according to a certain arrangement mode, namely a circular
metal sheet which is arranged at the central position of the upper surface of the
dielectric layer, and the center of the circular
metal sheet is aligned with the center of the upper surface of the
dielectric layer; three annular metal sheets concentric with the circular
metal sheet surround the periphery of the circular metal sheet, and gaps exist between the circular metal sheet and the annular metal sheet on the innermost layer and between the annular metal sheets on the adjacent
layers from inside to outside. And the four metal square sheets with the same size are respectively arranged at four corners of the upper surface of the
dielectric layer. The
absorption bandwidth is greatly prolonged, and perfect absorption of a target
wave band can be infinitely approached by adjusting geometric parameters of the absorber.