I am trying to visualize the field distribution of standing wave in HFSS, but can't get it.

  • The model is a simplest microstrip of 50 ohm. Two wave ports were appended to the endings and they are re-normalized to 500 ohm. Below picture is model together with field distribution of "ComplexMag_E", and the plane carrying field plot is in the middle of substrate;
  • S21 exhibits filter effect as expected;
  • My confusion is the field distribution is not standing wave pattern.
    •    The shade and color is basically even, but my expectation is gradual variation between red and blue;
    •    The pattern doesn't change, if I change the "Freq" setting. It is same regardless of Freq as 1GHz or 17.5GHz;

 

I suppose it is a very straight forward thing but it seems more complicated. Can anyone enlighten me?