However, the kite frame can only be grounded high-ohmic (which might be an unacceptable risk for testing personnel) or with at least one additional ground wire in the tether, and the electrical cable insulation would need to be much thicker or all electrical wires would need to be embedded in materials with similar or the same permittivity to sustain the electric field imposed by the voltage in the tether wires, because the electric field might then be not anymore (almost purely) radial from the litz wire. Therefore, also an approach with cables without shield is not considered in this study.
where [L.sub.te] is the tether length, [A.sub.c,w] is the litz wire's cross section area, [K.sub.c,w] is the specific conductivity of the material, and [f.sub.c,w] [greater than or equal to] 1 is a correction factor which accounts, for example, for the usual construction of a litz wire from a number ofstrands with which not the complete area might be filled with the conducting material (i.e., the fill factor is [less than or equal to] 1), increased temperature, manufacturing inaccuracies, material defects, the helical placement through which the length of the electrical cables is longer than the length of the tether, and onboard and on-ground cabling.
As only round wires are considered, a litz wire's cross section area is
Finally, because we chose to use Litz wire
, we expected to see little variation at different frequencies.
coil inductance is 21uH and this coil type was used in experimental tests.
A., "Analytical computation of AC resistance of round and rectangular litz wire windings," IEE Proceedings B, Electric Power Applications, Vol.
Viarouge, "Accurate analytical model of winding losses in round Litz wire windings," IEEE Transactions on Magnetics, Vol.
[25.] Acero, J., et al., "Frequency-dependent resistance in litz wire planar windings for domestic induction heating appliances," IEEE Transactions on Power Electronics, Vol.
A Litz wire structure is adopted in the receiver to reduce the ohmic loss of the receiver, as in .
The existing solution exceeds the simulation results (blue curve) at corresponding frequency (~800 kHz) because a Litz wire is used  instead of a plain coil, as was used in simulation.
The network is demonstrated with copper and litz wires
to obtain a high quality-factor.