Numerical homogenization and synthesis of wave polarizers through the Material-by-Design paradigm
A Material-by-Design (MbD) strategy is introduced for the design of multi-layer wave polarizers based on metasurfaces with arbitrarily-shaped unit cells. Following the MbD paradigm, the design is carried by integrating a solution-space exploration block, an electromagnetic simulation block (exploiting a full-wave Method-of-Moments with periodic boundary conditions), a homogenization block, and a cost function evaluation block. Numerical example showing the effectiveness of the proposed strategy is presented.
Metamaterial-enhanced arrays by innovative QCTO approaches
Quasi Conformal Transformation Optics (QCTO) is applied in innovative antenna array enhancement applications. The QCTO is implemented numerically. Examples provided include miniaturization of a linear array using isotropic metamaterial lens and transformation of an arbitrary shaped conformal array to a well known (for example circular) array. A full-wave electromagnetic simulation is used to validate the approach.
Global attractivity in time-delayed predator-prey systems
Abstract For a predator-prey model with time-delay due to gestation, criteria are obtained for persistence and global attractivity. The global attractivity criteria apply only to models with a decreasing prey isocline.