Which is accurate, HFSS or CST?

Hi my friends:
I have designed a waveguide polarizer with screws. When i optimized with the HFSS and got a satisfacory result, i decided to use CST to verify the results. But the simulation turned out that the VSWR and transmission amplitude are correct, but the phase difference is 104 degree(while in HFSS it is 90 degree). I hope i can get your advice and experience, which software is reliable?
Thank you very much!

Your results will depend on the number of meshes given for the simulation. Check for that.

the way you define boundary conditions in two s/w is different..so i advise you to thoroughly check them. Both the softwares are good and accurate.

In HFSS, when simulating an waveguide component , it is not necessary to define a boundary condition. How about CST? I am not very familiar with it, can you give me some advice or examples?

Hi fishyxl
I think the hfss is more accurate in calculation S parameters in waveguide structure . When I simulation an antenna , I can get accurate pattern in HFSS and CST-MWO ,but in calculating S parameters ,HFSS is better than CST .
Regards!
caocao

When I was simulating an paper in IEEE (I am sorry i forgot the name of the paper, but the irises are eplliptical), the VSWR and apmlitude met with the literature, but the phase difference is 80 degree in HFSS whilte it is 90degree in CST. Can you help me to cope with it?
Thank you very much!