Learning Forum

[muncc]

Lets say we are trying to simulate a 2D structure of conductive patches that are in an array of equal distance of each other on XY plane in vacuum which are hit by a plane wave of TE and TM modes at an angle of Theta, we want to measure the s-parameters in this scenario. And see how much power actually penetrates the structure in any typical frequency of the range 0.1 GHz to say 10 GHz. 

I need to perform the simulation both for TE and TM impinging waves. and measure the S parameters.

My question is that:

1- How many Floquet ports do we need in this scenario? Should we use a Floquet port in either side of the structure? 

The reason that I ask this question is that I have seen that in one of Ansys tutorials where they have simulated an array antenna, they have used just one Floquet port on one side and a wave port on the other side. Why don't they use another Floquet port as an excitation instead of the wave port?

2- Lets assume we use 2 Floquet ports. Right clicking on the excitation and then choosing edit sources, it shows that the magnitude of Floquet port 1:1 (which is port one mode TE) is 1 but the rest of the values are 0. If we need to see the result for both TE and TM modes, should we also change the magnitude of Floquet port1:2 to 1 or we should leave it to be 0? If we change that to 1, does it mean that the port excites the structure with TE and TM modes simultaneously? or it does it separately? I mean by setting both of the values to be 1, does it mean we have the TE and TM modes hitting the structure at the same time? (doesn't it mean it is a wave of linear polarization at 45 degrees of x and y axis? ) If not, what should we do for that?

3- what is the correct way of setting the frequency sweep? Can I use discrete sweep type? Or it must be interpolating? does it affect the results? what is the difference and which one is better?   

4- I have simulated the structure in a discrete sweep type. I found that different values for Maximum Delta S (under Analysis>Setup) of the simulation, result in different values for s Parameters! Do you have any idea why changing Delta S affect the S parameters so much? I expected it to just make the S parameters values more precise, not to change them completely. 

5- after deembedding the ports in a way that makes sure they are far enough, should we just include propagating modes in mesh refinement or we need to include the other modes also? 

 

6- can we use floquet ports for a structure which just has symmetry over one axis? for example a 2D structure on XY plane, which is symmetric with respect to x axis? How can we do that? Should we set the other boundaries to PML or Radiation?

 

7- If the wave hits the structure at an angle of Theta= 60, how should we set the parameters for mode selection in mode calculator? (Should I set Theta to be 0 to 60 to span all angles in between or it should be just a single angle of 60 for both start and end angles?)

 

8- Do I need to specify the resolution of the geometry in the simulation or the automatic detection is always enough? (resolution : size of the smallest structures in the geometry)

 

9- If I need to mesh some parts of the structure manually, do I have to use "on selection" or "inside selection"? and what is the difference?

 

Thanks! 

[Sorceress Gia]

Are you trying to simulate an infinite array of patches? 

[muncc]

yes. I'm trying to simulate the incidence of a plane wave on an array of patches using floquet boundary conditions.

[noamannaseer]

Hi, have you able to get answers to your queries, I also have the same queries along with mode selection during excitation. How can we excite wave port and Floquet port with desire TE or TM mode n

[Praneeth Munaga]

Hi,nPlease go through the following responses to the questions in the same order regarding:nThe floquet port quantity depends on your need. If you want to analyze reflection properties of a structure only then one port is sufficient otherwise you can have two ports.nPlease go through Scaling a Source's Magnitude and Phase section of the Help document.nPlease go through Discrete Frequency Sweeps in HFSS and Interpolating Frequency Sweeps in HFSS section of the Help document.nGenerally, if simulation converges then there will not be much change in your results with increasing number of passes. We can comment precisely only after seeing your convergence profile. Please share its screenshot.nPlease go through Deembedding section of the Help document.nI will get back on this query shortly.nPlease go through Floquet Port:Modes Calculator section of the Help document.nPlease go through Specifying the Model Resolution section of the Help document.nPlease go through Length Based Mesh Refinement section of the Help document.n