Learning Forum

[liguangrui33]

Dear Sir or Madam,

I am trying to simulate imaging of a periodic structure. While using gratingpolar function I can have clear diffraction orders on the far field, using farfieldpolar I saw oscillations from the diffraction orders in direction normal to the boundary of the simulation region. My question is what is the physical difference between gratingpolar and farfieldpolar functions beside normalization of the sum(|E|^2) with gratingpolar?

Thank you.

[Guilin Sun]

 

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Grating analysis scripts assume infinite number of periods, thus it uses plane waves for the decompision of the monitor data.

farfield script is for non-periodic structure, and it uses the standard near-2-far transformation in FDTD community. You may find a book chapter by searching

Chapter 14
Near-to-Far-Field Transformation

 

 

 

[Guilin Sun]