Learning Forum

[Stephen Robinson-Enebeli]

I modeled the scattering field of an incident plane wave on a sphere in HFSS. How do I compute the scattering and/or absorption efficiency of the sphere? I would like to compare this to the Mie solution.

[Faezeh Ladani]

Hi Stephen, 

You can use Fields calculator to calculte the power loss density inside the volume of the sphere for absorption, and also scattered power through integrating poynting vector on a closed surface (an sphere with slightly larger radius in air). For absorption, you should consider the total field, but for scatterring you need to only look at scattered fields, so select it properly in Edit Sources.. (Right click on Excitation>Edit Sources). 

Online help has related examples for fields calculator. search for "Calculating Dielectric (or Conduction) Loss in a Volume" and "Calculating Net Power Flow through a Surface". 

 

 

[Stephen Robinson-Enebeli]

Hi Faezeh,

Thank you for your reply. I actually was able to calculate what you described and your description validates my approach. The issue is that to get the efficiency, I need to compare it to the total incident electromagnetic power on the surface of the sphere. This is particularly what I am having difficulty with. 

[Faezeh Ladani]

Hi Stephen, 

To get the incident power, you just follow the same approach for fields calculator. Just in Edit Sources, use Incident Field in advance. Then whatever fields calculator expression is being calculated based on incident field.