New To Microstrip TL Sim ?

why such strange result ?

for 10 GHZ MicroStrip TL air substrate W=2mm h=0.5mm 50-55 ohm
using ansoft hfss



the result less than 25 ohm ?



plz any tips about WavePort dim? Int Line ? ....etc


thx all

I find the section in the on line help (HFSS) on impedance calculation particularly helpful.

You might look at the field at the port(s) and see if it is as you expect.

You may also want to use anther calculator to see if it gives similar results. There are a bunch of free packages on the web. Polar is pretty useful with a wide selection of lines modeled.

Lastly there are two books that I find useful: Waddel and Simon. Between them a wide range of transmissiion lines are discussed. Zo equations are provided to do a manual calculation.