Novel coils topology intended for biomedical implants with multiple carrier inductive link

Biomedical implants require wireless power and bidirectional data transfer. We propose a novel topology for a multiple carrier inductive link and compare two geometries for it. The orthogonal approach and the coplanar approach are these geometries. The principal challenge with multiple carriers is minimization of crosstalk, especially of power into data under lateral misalignment of the inner and outer coils. We show that a coplanar design allows keeping coupling of power into data under 15% with respect to the data coupling, even under lateral misalignments over 5 mm. In comparison, the orthogonal geometry reaches over 50% of parasitic coupling after a displacement of only 3 mm.