Figure 7: 3D calculated PBS for a 3D structure based on alternating Psi layers of 40 and 80% porosity and thickness each. Bands are plotted along main symmetry lines of the Brillouin zone, where frequency is given in normalized units (). Left inset, the schematic representation of 3D structure used in the simulations is represented. In dark blue the low-porosity Psi layers and in light blue the high-porosity Psi layers are shown. Right inset, the representation of 3D Brillouin zone is shown.