Hello Altair Community,
I have a questions regarding a waveguide simulation. I have designed a WR-1800 waveguide in Cadfeko and would like to view which modes can propagate in my given frequency range and if, how the field lines look like. I have tried setting up a CMA but I see some issues with the results. When I plot the fields in Postfeko (for example Mode 1), the field lines do not look as expected (assuming Mode 1 means the fundamental mode TE10 for rectangular waveguides).
My waveguide has the dimensions of a WR-1800 waveguide and is simulated at a frequency of 450 MHz. The model looks as following (simple cuboid):

It is closed on both sides because Feko gives the error "Modal analysis not possible with ports". After meshing, I simulate the model with the following requests:
CMA:

Near Field Request:

After the simulation is finished, I would like to view the fields inside the waveguide. To do that, I have simply plotted the near fields in Postfeko also activating the arrows that show the field direction. Assuming that "Mode 1" is the fundamental mode (TE10), I would expect the field lines to look like this:

However, Feko shows the field lines for the Mode 1 as following:

I am not quite sure if I have a correct simulation setup for my purpose of showing the field lines of different modes or if I am interpreting Mode 1 correctly as TE10. If this is not correct, could you please help me to set up a simulation for my purpose?
I have attached my Cadfeko model here.
Thank you in advance!
Best regards
Fatih