Design of low-loss PCB Litz wire with planar spiral coil for wireless power transfer

Planar spiral coils in high-frequency wireless power transfer systems suffer from increased loss due to skin and proximity effects. The PCB Litz wire structure is proposed to suppress eddy current losses and improve the quality factor. Optimized design parameters are obtained through theoretical analysis and electromagnetic simulations. Simulation results confirm reduced AC resistance in the kilohertz range and a higher quality factor compared with conventional solid-wire coils. The proposed approach provides an effective solution for high-performance and compact WPT systems.