Toward flexible ferromagnetic-core inductors for wearable electronic converters

This paper presents flexible and deformable inductors using nanostructured flexible magneto-dielectric materials for wearable electronic converters. Polymer-hybrid nanoparticles dispersed in an elastomer matrix contribute to high saturation magnetization (M_s) and low coercivity (H_c) of magneto-dielectric composite. The rubber nature of ferromagnetic-core inductors based on nanoparticle-elastomer composites provide the potentials of mechanical elasticity, deformability and lightweight of wearable devices. Nanoparticle structured composite increases the geometric plasticity in customizing components. Their high magnetic resonance frequency (f_res), relative high magnetic permeability (μ) and low corecivity (ε) allow high frequency operation of power converters toward wearable electronic miniaturization. Furthermore, low dielectric and magnetic loss of polymer-hybrid composites improve the efficiency of power converters, especially at high frequency operation. A 10-W boost converter is fabricated using different flexible ferromagnetic-core inductors to evaluate the feasibility and the electromagnetic performance of the flexible material. The converter has potential capability of plastic deformation under tensile elongation up to 70% strain.