Bobina Bipolar

A bipolar coil arrangement creates regions of opposite magnetic polarity in the coupling zone, often by splitting the winding into two halves driven or connected so current flows in opposing directions in spatially separated loops. Bipolar patterns appear in some WPT topologies to shape the field for misalignment or to interface with specific compensation networks.

Compared to unipolar (single-direction flux) spirals, bipolar fields can exhibit nulls and steeper spatial gradients — useful or harmful depending on receiver geometry.

01Potential benefits

• Shaped coupling map for specific offset directions.
• Compatibility with certain multi-coil decoupling schemes.
• Reduced net DC field component in some arrangements (sensor interference).

02Design cautions

Receiver coils must be sized and oriented to link the intended bipolar flux — a small receiver centered on a field null couples poorly. FEM maps of |B| and coupling phase are essential. Termination symmetry matters; unequal half-coil resistance causes field imbalance.

03Testing

• Flip receiver 180° and compare k — asymmetry reveals bipolar imbalance.
• Measure open-circuit voltage phase along lateral sweeps.
• Verify no unexpected torque on ferrite or metal parts near the pad.