Efficient way to simulate Sievenpiper structure

[kumagai]

Hi,

I tried EM Talk tutorial.

h$$p://www.emtalk.com/tut_3.htm

But it took a lot of time to simulate 3 modes.
Do you know other Efficient way to simulate Sievenpiper structure except HFSS?

For example, can MIT Photonic-Bands (MPB) simulate Sievenpiper structure?

thanks!