High frequency meta-ferroelectrics by inverse design

Composites with subwavelength features exhibit effective properties that depend on microstructure morphology and materials, which can be adjusted to obtain enhanced characteristics. We detail the systematic design of electromagnetic metamaterials composed of dielectric inclusions in a ferroelectric matrix that, under an applied voltage, present an optimized effective tunability higher than the bulk due to a nonlinear local electric field enhancement. The effect of volume fraction, losses, and biasing field on homogenized properties is investigated and the analysis of the photonic band diagram is carried out, providing the frequency dependence of the anisotropic effective index and tunability. Such metaceramics can be used in microwave antennas and components with higher reconfigurability and reduced power consumption. Multifunctional and reconfigurable systems are increasingly demanded for a wide range of applications in Electromagnetics and Photonics [1-3]. In parallel, the development of artificial media and metamaterials [4,5], allowing unprecedented control of electromagnetic (EM) waves by carefully engineered subwavelength structures, has stimulated the research interest in tunable materials. Indeed, the ability to introduce tunable components has been established as a straightforward route to EM and metamaterials reconfigurability, albeit the added fabrication complexity in comparison with static devices. As a matter of fact, it is envisioned that reconfigurable metamaterial structures have the potential to mitigate some of the most significant limitations of static metamaterials such as narrow bandwidth operations, high losses, and tolerance sensitivity. Often, in addition to the necessary control logic, adding reconfigurability to a metamaterial structure requires the introduction of extra components and materials to a standard design, hence potentially affecting the system's performance, power consumption and weight. Consequently, there are still significant theoretical and technical obstacles to the production and deployment of reconfigurable metamaterials within commercial products, particularly regarding