Figure 1. Model and simulated performance of a passive metamaterial.

(a) Model of a passive metamaterial with double-negativity based on periodically distributed membranes and side holes along a pipe. (b) cos (qL), (c) dispersion Re(qL), (d) transmission spectra and (e) equivalent density and modulus of the tunable metamaterial before the electromagnets are electrified, which are calculated with the parameters: a unit length L = 10 cm, a radius of main pipe a = 1.3 cm, a radius of side hole r = 1.1 cm, a mass of membrane m_M = 3.78 mg, a stiffness of membrane k_M = 1275 N/m, a unit number N = 10, and the parameters of air ρ₀ = 1.21 kg/m³ and c₀ = 344 m/s.