Symbol	Definition
$L_T$, $L_0$, $L_i$, and $L_{Ri}$	Inductance of the source loop, resonator-0, resonator-i, and load loop-i
$C_T$, $C_0$, $C_i$, and $C_{Ri}$	Capacitance of the source loop, resonator-0, resonator-i, and load loop-i
$R_T$, $R_0$, $R_i$, and $R_{Ri}$	Resistance of the source loop, resonator-0, resonator-i, and load loop-i
$R_S$ and $R_{Li}$	Source resistance and load resistance
$d_{T0}$, $d_{0i}$, and $d_{Ri}$	Vertical distance between the source loop and resonator-0, resonator-0 and resonator-i, and resonator-i and load loop-i
${\rho }_{0i}$	Lateral displacement from the center of resonator-0
$k_{T0}$$, k_{Ri}$, and $k_{0i}$	Coupling coefficient of the transmitter, load, and receiver
${\kappa }_{T0}$$, {\kappa }_{Ri}$, and ${\kappa }_{0i}$	Normalized coupling coefficient of the transmitter, load, and receiver
$U_{T0}$, $U_{Ri}$, and $U_{0i}$	Coupling factor of the transmitter, load, and receiver
${\mathsf{\Gamma }}_T$, ${\mathsf{\Gamma }}_0$, ${\mathsf{\Gamma }}_i$, and ${\mathsf{\Gamma }}_{Ri}$	Loss rate of the source loop, resonator-0, resonator-i, and load loop-i
$Q_T, Q_0, Q_i, \mathrm{and} Q_{Ri}$	Quality factor of the source loop, resonator-0, resonator-i, and load loop-i
$Z_{RRi}$, $Z_{Ri0}$, and $Z_{RS}$	Reflected impedance seen from the load loop-i to resonator-i, from resonator-i to resonator-0, and from resonator-0 to the source loop
$M_{T0}$, $M_{0i}$, and $M_{Ri}$	Mutual inductance between the source loop and resonator-0, resonator-0 and resonator-i, and resonator-i and load loop-i
$x_i$	$\mathrm{Normalized} \mathrm{external} \mathrm{loading} (=R_{Li}/R_{Ri})$
$I_T$, $I_0$, $I_i$, and $I_{Li}$	Current in the source loop, resonator-0, resonator-i, and load loop-i
$P_0$, $P_i$, and $P_{Loop,i}$	Power transferred to the resonator-0, resonator-i, and load loop-i
$P_{IN}$, $P_{LOSS}$, and $P_{Li}$	Input power, loss power, and output load power
$\mathsf{\Sigma }{U}_N$	Overall loading of N receivers
$r_{mn}$	Power ratio between two receivers
${\eta }_E$ and ${\eta }_T$	System efficiency and overall power transfer efficiency
$U_{T0,opt}$	Optimal coupling value for maximum power transfer efficiency
$d_{T0,opt}$	$\mathrm{Optimal} \mathrm{distance} \mathrm{corresponding} \mathrm{to} U_{T0,opt}$