HFSS simulation problems

Hello! I wanna know that whether there will be any effect on the results if i change the material from from vacuum to something else in HFSS? Also what is the criteria for checking the results when i simulate a magic tee?

Hello,

When E-field lines generated by your structure cut your dielectric, properties will change. Increasing relative epsilon will reduce the propagation speed in transmission lines that share the higher relative epsilon. Characteristic impedance of transmission lines reduces, cutoff frequency for wave guides reduces, etc.

Even microstrips will have higher propagation delay when you put another dielectric layer on top them.