Stacked flexible parylene-based 3D inductors with Ni80Fe20 core for wireless power transmission system

This paper presents a new high quality factor parylene-based stacked 3D spiral inductor with Ni₈₀Fe₂₀ core for wireless power transmission system. To achieve multilayers, planarization of parylene by oxygen plasma etching was realized. Ni₈₀Fe₂₀ was added as the magnetic core to enhance the performance. The maximum quality factor of the designed circular double-layer inductor reached 99.3 at 60MHz, which is much higher than the square coils with the same area. The double-layer inductor shows a 408% increment of maximum quality factor compared with single-layer coil. Furthermore, inductors with magnet arrays exhibited better performance than those with one magnet. Forming the power transmission system with these 3D inductors, the minimum attenuation was -26dB at 118MHz.