reflectarray cell element Floquet excitation in HFSS

Hi all,

I am now modelling a reflectarray cell element in HFSS, but come across a problem when setting the Floquet excitation. I have drawn an airbox, four sides of it are assigned with Master/Slave boundaries and the bottom side left with empty and align with the ground of the cell element. The top side is set as 60mm away from the upper rectangular ring which is backed by a dielectric and assigned as Floquet port excitation. I wonder is my setting up enough and correct? Because I have read some articles saying another Floquet port needed below the cell element as well (something like mirror effect?).

anyone can help? Thank you very much!

J

Also, do I have to obtain the reflection phase at the rectangular ring plane, which can be de-embedded from the floquet port? I think it's just a relative phase relationship, you can up-shift or down-shift the curves to the range you want. Am I right by saying this?

J

Since reflect array has zero transmission as it sits on a ground plane, one Floquet port is all you need. De-embed the Floquet port to the point of measurement. For reflect arrays I usually de-embed to the surface as the phase of reflection on the surface is the quantity of interest for me. As an aside, Floquet ports should always be on an outer face of the unit cell, I am a bit puzzled about the dielectric that is mentioned.

have Fun!

Hi thanks for your kind response! Yeah, I agree, for this case one Floquet port is enough.

Dielectric mentioned here means the substrate which backs up the metal patch.

But I am still a bit confused that must I de-embed the reflection phase to the element surface? I think what I want is just the relative phase relationship between each elements and I can normalise it anyway even without de-embedding (the reflection phase curve shapes are in the same trend with the variation of the Floquet port location), am I correct? can help?

J

anyone can help?