irradiation simulation

[baryons]

Hi,

HFSS is very suitable for calculating s-parameters or radiation from objects. However irradiation is not so intuitive. I'm interested in a problem where a trace over a ground plane is illuminated by a plane wave of arbitrary angle of incidence. The objective is to find the coupled field intensity at the line ends (open or resistively terminated). When I contacted the local FAE he suggested me the field calculator and sent me the documentation for that. Even with it, I find the setup and solution quite unintuitive and still struggling with the problem. Due to the relatively low application rate of the case, I observe the Ansoft engineers are not very used to this kind of problems either. I'd like to find out if any one out there had any experience with such a problem and would care to share his opinion on this forum.

Thanks

Ian

[sjapollo]

Incident field solutions in HFSS *are* somewhat confusing. When you combine them with lumped or wave ports, it gets even more confusing. The basic methodology for exciting a plane wave is to use the HFSS / Excitations / Assign / Incident Wave / Plane Wave option. From here you describe the E-field polarization and k-vector. It's easiest and most flexible to describe the incident wave in terms of Spherical CS. From here, you can terminate a transmission line in a lumped port or a LumpedRLC boundary condition, and then, yes, use the Field Calculator to calculate the power flow through the termination.

To calculate power flow in the field calculator, you must first have a 2D geometry defined in the 3D modeler. Here are the steps:
Quantity / Poynting (this is a complex vector quantity)
General / Complex / Real (take only the real part of the Poynting vector. This leaves a vector quantity)
Geometry --> Choose Surface, and then select the name of your object
Vector / Normal (selects the normal vector to your geometry, and dots that with the vector Poynting qty)
Integrate

Then you can Evaluate the expression, or select Add.. to create a custom expression that can be plotted versus frequency, angle, etc.

I've attached a project here that has a completely parameterized project using Project variables. Make note that even the Etheta and Ephi are parameterized. In this example power is actually coupled to the lumped ports when Ephi=0 and Etheta=1.

microstrip_planeWave.zip

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