Tunable Multiferroics for Reconfigurable RF System Packages

Abstract

Electric and magnetic properties of multiferroics can be conveniently tuned with applied electric and magnetic fields. Such tunability provides multiple design options for reconfigurable antennas and smart shielding applications and is thus of high interest. Dielectric tuning is commonly achieved with electric fields, which is more suitable with thin-films as they need lower voltages. For thick RF dielectrics that are used in antennas and Frequency Selective Surfaces (FSS), tuning requires 100s of Volts. To address this problem, we propose current-driven tuning of permittivity with integrated coils under the multiferroic. Tunable dielectric properties in nanostructured titanate paraelectrics are investigated through simulations by coupling them with magnetostrictive layers. In parallel, cosintered ferrite and paraelectric dielectrics are characterized for their tunability. The change in dielectric constant with magnetic fields is analyzed through multiphysics COMSOL simulations. Permittivity tuning is modeled with different coil currents. Applications in tunable FSS is demonstrated with such dielectric tuning.