Learning Forum

[zouxie]

Dear Sensei.

In the far field setting, 'Assume structure is periodic' is checked and the appropriate x, y, z periods are set. I will be able to get the far-field reflection angle close to the expected result. Otherwise, the results obtained will be 1.5° off from what is expected.

I would like to know: why I get the expected far-field reflection angle only after phase correction. Looking forward to your reply. Thank you

I've studied this one.

 

 

[zouxie]

I've studied this one.

[Guilin Sun]

Thank you for finding the solution!

As the website says, "assume periodic" is an approximation, since the simulation with plane wave +periodic BCs assumes infinite periodicity.  When it is approxiated to be finite number of periods for farfield projection, a window function is added. The result is similar to convolution of the simulated periodic fields and the window function.

[zouxie]

Thanks for your reply.

Maybe I can understand your reply like this? For more accurate far-field results, the finite number of periods and 'Assume structure is periodic' are used in pairs.

[Guilin Sun]

In your case ther unit cell (one period) contains several teeth with different size, right? using grating analysis gets the result from infinite numbber of periods. If you want results from finite number of periods, yes you have to use "assume periodic" to approximate it.

 

 

[zouxie]

Ok, thank you for your patience in replying. My problem has been solved.

Have a good day~~