A. Optimal Load Impedance according to Cross Coupling
The target distance DL between Tx and Rx coils is 1 cm. For
simple calculation, it is assumed that receivers are identical and
placed on the same radial positions, that is, rotationally
symmetric as shown in Fig. 1(a). Hence, ML1=ML2=···=MLn.
The Tx coil has concave mutual inductance pattern according to
the lateral displacement when DL=1 cm. The maximum value is
achieved as ML=539 nH when