Wednesday, November 10, 2010
More Lollypop forests - in HFSS
Heath from our lab gave me a primer in Ansoft HFSS and since then I have been muddling along to try and represent a forest for SAR imaging. I managed to get some of my ngPlant created models into it via STL from Blender, but beyond that HFSS was totally non-cooperative. The model refused to be healed to close any of the perceived holes etc. So my only option was ot make some Lollypop trees like before using the supplied primitives, in 3D this time. Fortunately HFSS allows quick duplication, scaling etc. of a single primitive and links them with transform nodes. In the future this will allow more stochastic forest generation rather than a cookie cutter one.
FEM kicks in beyond this point and calculates the scattered far fields with plane wave excitation. As expected due to the perfectly conducting ground plane most of the energy radiates away, but there is still some significant return towards the illuminating direction.The nice change from FEKO is that the fields are calculated in all directions, not just the illuminating direction. So this setup can be used to bistatic imaging scenarios as well.