Learning Forum

[parksb2002]

Hello,   I'm trying to calculate the transfer function of antenna input to resulting electromagentic fields at locations that I desire to obatian the time series. For two port system, I successfully get the time domian plot with smooth pulse as input.

 Now I want to calculate the electromagnetic field around the antenna to calculate the time response of electromagnetic field depends on the input signal. I try to make a near field radiation as I did for other non transient analysis, but when I change the solution type to transient, near field radiation menu is deactivated. I guess there is some restriction for transient analysis to make a near field data extraction but I want to make sure it is really impossible to do it.

 I know the electric field plot by the save field option for analysis setup can give me the overall distribution, but I want to obtain EB field time series in exact location.

Also, is there a recommended way to obtain the impulse response of antenna to electro magnetic field? or between two ports? Always thank you for your help.

 

Thanks,

S. Park

[Irina G.]

Hi,

my thoughts about transinet response to the design with 2 ports, say Tx and Rx antennas: it's usually better to use HFSS FEM solver in frequency domain and get S21 vs. frequency. Sometimes it's more effecient to use SBR+ or othe hybrid solver technoligies. Then one can transfer frequency response to time domein response, for example, using Circuit design in AEDT. Make sure that the freqeuncy band and frequency steps in reported frequency based S-parameter matrix is suitable for time pulse and duration of the time simulations. 

NF setup is not available in transient simulations: if it's closer to the antenna, save Field on a specific objects (plane or even a point) vs. time may fit the simulation goal. If the distance is far from antenna and in Far Field range, try to use Far Field vs. time report and estimate field as rE/R (the value of reported Far Field divided by the distance to the antenna phase center).  

[parksb2002]

 

Thank you for your answer!

For 2 port(Rx,Tx) analysis, your suggestion is the best option I think. Thank you so much.

However I need not only the port to port analysis, but also I want to calculate the response of em field according to the input of antenna. Reason why I need this is I want to mimicing the EM field which calculated by external tool by adjust the antenna input signal. Can I get the frequency sweep response for EM field also? like S21 vs frequency plot.

Best,

S. Park

[Irina G.]

In SBR+ design, you can solve for Near Field at the defined geometry (line, sphere, rectangle) if necessary.

Note that the solution is linear and S21 has all the info you need.