FIG. 3D shows a flowchart for operations in designing the small loop transmission coils 22. At operation 31, determining the value for the first set of feature sizes D1, D2, W and S for a first one of a pair of the small loop transmission coils 22 and according to a size of the primary coil antenna 21 and the quantity of small loop transmission coils 22 is performed. Supplying the D1, N, W and S values to the formula (2) in FIG. 3B, the value of inductance Lloop1 can be obtained. Further, supplying the Lloop1 value to the formula (1) in FIG. 3B at operation 32, given that a resonant frequency f of the small loop is 6.78 MHz, a value of series capacitance C1 for the first small loop transmission coil 22 can be obtained. At operation 33, a simulation model in the high frequency structural simulator (HFSS) is utilized in order to fine tune the first capacitance C1.
