June 2, 2021 at 4:03 pm
Guilin Sun
Ansys Employee
Let's first focus on the correct boundary conditions. Only when you set proper boundary conditions could you get correct result. If the wrong boundary conditions are used, even though the result is smooth it is not correct.
In XY axes PML should be used; in Z axis, Zmin can use "Symmetric" or "anti-Symmetric" but Zmax should use PML, or simply use PML at Zmin and Zmax.
Do not modify stability factor, which should only be modified when it causes diverge. Please use its original value of 0.99.
For bandstructure simulation, do not let the simulation converge to autoshutoff min, since this will only pick up the resonance with large Q so the band structure will not be smooth. From the online examples as you can see the simulations terminates very early where the autoshutoff level is around 90% or higher. This is because such simulations are used to extract the resonance information, not the exact amplitude.
When the simulation files have very different converge property, eg, for a given simulation time, one file terminates around 5% , another file terminates 100%, then you will need to manually resimulate the first file and let it terminates much early.
Such simulation is one of the few applications that the simulation terminates by the set simulation time not the autoshutoff min.
Please check
1: boundary conditions are correct;
2: simulation time is set to be much shorter than the default
3: check the log files or watch the simulation status to get the information when the simulation terminates.
and modify accordingly, and see what is the result. If there are still problems, please give screenshots:
1: the sweep panel shows the autoshutoff level, or check the log file and list them here
2: the resulting band structure
In XY axes PML should be used; in Z axis, Zmin can use "Symmetric" or "anti-Symmetric" but Zmax should use PML, or simply use PML at Zmin and Zmax.
Do not modify stability factor, which should only be modified when it causes diverge. Please use its original value of 0.99.
For bandstructure simulation, do not let the simulation converge to autoshutoff min, since this will only pick up the resonance with large Q so the band structure will not be smooth. From the online examples as you can see the simulations terminates very early where the autoshutoff level is around 90% or higher. This is because such simulations are used to extract the resonance information, not the exact amplitude.
When the simulation files have very different converge property, eg, for a given simulation time, one file terminates around 5% , another file terminates 100%, then you will need to manually resimulate the first file and let it terminates much early.
Such simulation is one of the few applications that the simulation terminates by the set simulation time not the autoshutoff min.
Please check
1: boundary conditions are correct;
2: simulation time is set to be much shorter than the default
3: check the log files or watch the simulation status to get the information when the simulation terminates.
and modify accordingly, and see what is the result. If there are still problems, please give screenshots:
1: the sweep panel shows the autoshutoff level, or check the log file and list them here
2: the resulting band structure
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