{"id":359412,"date":"2024-03-28T10:40:33","date_gmt":"2024-03-28T10:40:33","guid":{"rendered":"\/forum\/forums\/topic\/bandstructure-disagreement-fdtd-vs-mpb\/"},"modified":"2024-03-28T10:40:33","modified_gmt":"2024-03-28T10:40:33","slug":"bandstructure-disagreement-fdtd-vs-mpb","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/bandstructure-disagreement-fdtd-vs-mpb\/","title":{"rendered":"Bandstructure disagreement, FDTD vs MPB"},"content":{"rendered":"
I have noticed a strong disagreement in bandstructure calculation in comparison to MIT photonic bands. <\/div>\n
 <\/div>\n
To demonstrate this, here is the bandstructure obtained from the band structure example: https:\/\/optics.ansys.com\/hc\/en-us\/articles\/360041566614-Rectangular-Photonic-Crystal-Bandstructure<\/div>\n
Square lattice 2D TM mode:<\/div>\n

<\/p>\n

Calculating a bandstructure of exactly the same structure using MPB (https:\/\/mpb.readthedocs.io\/en\/latest\/) I obtain:<\/p>\n

Those band structures are more or less in agreement, the shape is identical, and the energy axis seems to be a little scaled (apparent at 0.4 energy scale)<\/div>\n
 <\/div>\n
Now, increasing the refractive index in both solvers to 10 leads to the following results:<\/div>\n

<\/p>\n

<\/p>\n

The shape of the bands is similar again, but this time, the energy axis is drastically scaled. Other calculation methods hint towards MPB being correct.<\/div>\n
How do I combat this issue of energetical disagreement for high permittivity simulations?<\/div>\n
 <\/div>\n
Thank you,<\/div>\n
Martin<\/div>\n

<\/p>\n","protected":false},"template":"","class_list":["post-359412","topic","type-topic","status-closed","hentry","topic-tag-Photoniccrystal-1","topic-tag-bandstructure-1","topic-tag-fdtd"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t