structural evolution design and optimization for the metamaterials with broadband frequency-independent negative permeability

Broadband frequency-independent operations are strongly desired in metamaterial applications. in this work, we unveil the roles of each element acting in the metamaterial unit with a structural evolution design methodology. starting with “split ring resonator” (srr) prototype structures, we focus on the variations of elements on the magnetic response and successfully realize the structures of “clock-like” and “wire pairs” with double and broadband frequency-independent negative permeability (0.725 to 0.9 thz, μ = − 0.75). our results suggested that multi-resonance modes induced by elements integration could extend working bands. by well parameters tuning, the phase mismatch during multi-modes interactions could be utilized to modify the working bands with frequency-independent features as well. our investigations are beneficial to the design of functional negative permeability metamaterials with broadband operations.