Figure 4. Measurements of phase velocities tunable metamaterial.

(a) Quasi-sinusoidal signals containing the wave fronts measured in the N-th (solid line) and (N + 1)-th (dashed line) units at 630 Hz; (b,c) zoom-in of the wave fronts and the zero-crossing points obtained in the twenty-fifth periods of the signals from (a,d) detected signals at 650 HZ with the driving voltage of 0 V; (e) detected signals at 650 Hz with the driving voltage of 6 V. (f) Theoretical and experimental phase velocities in the DPB under different driving voltages supplied to the electromagnets.