Fig. 4: WPT performance of the WTCL.

a (I) Schematic and (II) experimental setup of the WPT experiments. b Reflection coefficient spectra (S11 and S21) were recorded from four receivers at different radiation distance. c The S21 recorded by the four receivers at 850 kHz were plotted as a function of radiation distance. d Alternating voltage signals collected from four receivers wirelessly under different frequency radiation at 20 Vpp applied on the transmitter, and (e) Wirelessly transferred alternating voltage waveforms of four receivers under different radiation distance at 20 Vpp applied on the transmitter, and (f) the Vpp were plotted as a function of frequency and (g) as a function of distance. h The wirelessly transferred voltage signals collected by Rec#17 were activated by SquWave or SinWave voltages at different frequencies, and the Vpp were plotted as a function of (i) frequency or (j) distance. k Heatmap plot summarized the Vpp recorded from four receive circuits under different voltage-transfer conditions, including the coupling frequency, the radiation distance, and the waveforms.