Dependencies of dynamical magnetic losses in conductor-coated dielectric particles on radius of dielectric core, thickness and conductivity of conductive shell

In this work, we modeled dielectric spherical particles covered by metallic layer. We obtained dependencies of real and imaginary parts of the effective permittivity and permeability of powders from metalized dielectric particles on the frequency, radius and permittivity of the particle, thickness and conductivity of the metallic layer. We used finite element method for calculation of the electromagnetic fields in the investigated model and combination of impedance lows for ideal conductor and ideal magnetic mirror to calculate effective electrodynamics parameters. Novel technique for calculation of effective permittivity and permeability from results of direct calculations of electromagnetic fields in the model is provided in this paper. The imaginary part of the effective permeability is large enough compared with imaginary part of the effective permittivity and reaches its maximum values at the thickness of the metallic layer less than the skin depth. Therefore, microwave heating of such particles is due to dynamic magnetic losses. Moreover, the imaginary part of the effective permeability for metallized dielectric particles can be nearly twice greater than the one for entire conductive particles.