DOOM86
Newbie level 3
Hello to everyone!
I'm actually working on photonic crystals, in particular I'm trying to evaluate the photonic band gap, through dispersion diagram, for a number of different lattice shapes.
I've already successfully did a square lattice, but for now I'm unable to obtain valid results for a rhomboidal lattice, like that of the screenshot appended.
I know that, to calculate the dispersion diagram, the irreducible Brillouin zone must be scanned. This is fundamentally a triangle in the xy plane (I'm doing everything for 2D photonic crystals).
The problem is (I think) that CST automatically assign a cubic or parallelepipedal boundary box to the structures being simulated, and then one must set periodic boundary conditions in the xy plane. This is ok for a square lattice, cause the structure is perfectly contained inside the boundary box, but for a rhomboidal form some box volume remain unfilled and the periodic boundary condition lead to an inaccurate solution.
To this date i was unable to shape a perfect rhomboidal boundary box in CST and I think this is impossible because the simulator sets automatically the box outside the geometry.
Moreover, I also found impossible to assign master-slave conditions to opposite sides of the structure, like one can do in HFSS for example.
Any suggestions on how to simulate a structure like this? Did anyone successfully did it?
Thanks to everyone!!
I'm actually working on photonic crystals, in particular I'm trying to evaluate the photonic band gap, through dispersion diagram, for a number of different lattice shapes.
I've already successfully did a square lattice, but for now I'm unable to obtain valid results for a rhomboidal lattice, like that of the screenshot appended.
I know that, to calculate the dispersion diagram, the irreducible Brillouin zone must be scanned. This is fundamentally a triangle in the xy plane (I'm doing everything for 2D photonic crystals).
The problem is (I think) that CST automatically assign a cubic or parallelepipedal boundary box to the structures being simulated, and then one must set periodic boundary conditions in the xy plane. This is ok for a square lattice, cause the structure is perfectly contained inside the boundary box, but for a rhomboidal form some box volume remain unfilled and the periodic boundary condition lead to an inaccurate solution.
To this date i was unable to shape a perfect rhomboidal boundary box in CST and I think this is impossible because the simulator sets automatically the box outside the geometry.
Moreover, I also found impossible to assign master-slave conditions to opposite sides of the structure, like one can do in HFSS for example.
Any suggestions on how to simulate a structure like this? Did anyone successfully did it?
Thanks to everyone!!