Electromagnetic metamaterials are resonant, periodic structures (repetition of a unit cell) involving both dielectric and conducting elements, and are used and simulated in frequency ranges from microwave (a few hundred MHz) up to optical and more (up to PHz) frequencies. These structures are simulated in frequency domain using FEM.
My question is, considering the above properties of these structures, what properties (qualitatively) should the meshing of the unit cells of metamaterials have generally? More specifically, what are the benefits and drawbacks of using tetrahedral meshing versus hexahedral? (comparison)