The relation between the E-field and H-field in cavity HFSS simulation

- October 5, 2023 at 9:44 pm
  
  maryam.rahmani
  Subscriber
  
  Hello all,
  I'm running a simulation to find the E-field and H-field in a cavity using the eigenmode.
  I get the E-field in orders of 10^8 but H_field about 100 !!!! My question is that shouldn't the magnitudes of E and H be related by the intrinsic impedance that is calculated by z=377 ohm? Please see the below picture. The dimensions of the smaller side is the same size of WR-90 waveguid (22.86x10.16 mm) and the fields are shown for the second mode on 8.89 GHz. My question is even for the wave propagation in free space, is the |E| = 377 |H|. I appreciate your help.
- October 6, 2023 at 5:28 pm
  
  Faezeh Ladani
  Ansys Employee
  
  Hi MaryRah,
  There are two points to note here:
  1-The ratio of the E and H is not always supposed to be 377. This is only true for plane wave and antenna far field propagation. Usually in near field domain (and when we don’t have magentic material), electric field is stronger in orders of magnitude.
  2-Are you plotting Mag-E and Mag-H? The peak of the two fields can be out of phase especially in a cavity. Make sure to plot ComplexMag of the fields to get the total field phase-independent.
  Hoep this clarifies your question.
- October 6, 2023 at 5:55 pm
  
  maryam.rahmani
  Subscriber
  
  Thank you so much Faezeh for the prompt response.
  Yes, I was plotting the Mag-E/H. With the ComplexMag you suggested it looks much better as below:
  Best,