openEMS.de

Interesting.
And what is inside QT_PLUGIN_PATH ?

mesh, airbox dimensions, excitation setup, boundaries... check your script in that order.

there is no difference between primitives. Every object is converted into a set of rectangular boxes. so define the mesh carefully.

that's weird. As far as I understand, the engine treats every cell separately, regardless of continuity. First, I would check the metal definition. It may happen that one is a metal, and another is PEC, or something like that. It may happen also that the air, or substrate has a surpassing priority, ...

I guess, you are transiting From Rect to circ, and not back? so, isn't it obvious?

Or (probably), knowing approximate impedance you can add a lumped port along the expected field line corresponding the mode. It just creates a E field by driving the current through the port resistor.

I think, adding PML after the model and mesh is generated is a correct way. Calculating pml during mesh generation always creates troubles. I prefer making a model first, with an array of important structural nodes. Optimize the nodelist by removing duplicate nodes, and coordinate points within mini...

the answer is in your question. circular waveguide requires non-orthogonal meshing

Cylindrical coordinates can not be combined with rectangular. You will get stepped surface either in circular, or rectangular section. And it is easier to define circular section in rectangular coordinates, then the opposite.

The model of coax to feeding rect-horn works, but needs so dense mesh, that you better put a lumped port just inside the rect. section. Septum transition should also work just fine, but the circular waveguide is a problem. You will die increasing the mesh for accurate curved surface representation. ...

Feed is a transmission line connecting the device of interest to power source. You, probably mean a port. In general, most ports are voltages over a load block in OpenEMS, except plane wave excitation, which is represented by a cube with boundaries pulling a plane inside, and cancelling it outside, ...