Discussion Forum

Hello Everyone.

I'm an engineering student and I'm new in the COMSOL world. I am trying to simulate the behavior of a Horn Antenna. I set up my geometry, materials and physics quite a while ago and it's now been 10 days of unsuccessful troubleshooting. Not even my tutor could spot the problem in my model, and the deadline for this deliverable is next Tuesday. I really need some help. Below, I am going to briefly outline what I have done, for an easier understading of the model.

Basically, I first modelled my waveguide ("Flare") and my Horn ("Flare") and made a union of them, "Antenna". Next, I made my feed cable. It is divided it in two parts, the inner part that's sticking out inside the waveguide ("Coax Pin"), and the outer one which is also surrounded by dielectric. What I do next is subtracting all metal parts from the air domain: so it's "Sphere" - "Antenna" - "Coax Pin". Lastly, I take a difference between the cylinder of the dielectric and the cylinder of the outer pin, to get "Coax Insulator".

Now: the boundaries of air in contact with the pin and the antenna become PEC. The inside of the dielectric is also PEC, the outside is also PEC and the bottom face of the dielectric hollow cylinder is selected as coaxial-type lumped port. Of course I set Perfectly Matched Layers, Far-Field domains etc - you can check those in the model.

Everything looks fine to me, and so did to my tutor. However, if I run the study, I can not get any results. My convergence plot shows that the program is not getting anywhere.

Does anyone see the problem? I have also tried different approaches, e.g. starting with a simplified model with no thickness. I have already looked at COMSOL pre-made tutorials (e.g. Double Rigged Horn Antenna, Dipole Antenna, Mononopole Antenna Arrray, Coaxial to Waveguide Coupling), so please avoid just suggesting papers. I don't really have time left!

Regards, Matteo