Figure 1

Schematic of the set-up to realize the zero, inverse and normal Doppler Effect.
The whole experimental set-up. Vi(i = 1, 2…14) are the bias voltages provided to the CRLH TL units. The TL units in gray are set in zero-index passband (can also be LH, RH at different frequencies) while units in dark brown are set in band gap. vs is the moving velocity of the reflective interface.