unable to obtain the near field data after applying time signal.
I have applied a time signal(Gaussian pulse) on an aperture and I am to obtain the near field behavior. I am unsure if there is an error with the sampling or anything else. I am attaching my postfeko file here.
Answers
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Hello Niharika,
I can open your .pfs file with POSTFEKO, but no near-field in time domain is displayed, since no associated .fek and .bof files are linked.
Please also share those two here and .cfx file as well.
After checking the spectrum preview of your time signal setting, you need to use higher end- simulation frequency than 5 GHz in the CADFEKO setting.
Best regards,
Jaehoon
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I have attached all of them in this file.
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here you go
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Hello Niharika,
Thank you for attaching the files.
Due to some reasons (old version and mismatched file name), I can't open your files properly.
However, I can give some answers to your question.
As you can see the following picture from your .pfs file showing the frequency components of your time signal (Gaussian pulse). It indicates you need to solve the .cfx file from almost DC to higher than 5 GHz (10 GHz is recommended if considering -60 dB amplitude attenuation).
However, you need to also consider your main field source, rectangular waveguide which operates as a high pass filter. I mean you can not get any field values below the cut-off frequency.
This is very similar to the case where a dipole antenna (having one resonant frequency) can not be used to transmit the broadband time signal (Gaussian pulse).
Please try to run the Feko solver from DC (a few KHz) to 10 GHz with continuous frequency sweep. You might have some result..but I am afraid that's not the exact time response (near-field) for the Gaussian input time pulse.
Best regards,
Jaehoon
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Thank you for your response. Since the waveguide's dominant mode cut off is at 3.12GHz, will it still not transmit the pulse from that frequency up to 5GHz? I was hoping this logic would work with the pulse.
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I'd like you to first try with a narrow signal (like sine wave) which is covered by the waveguide port to see the accurate time (near-field) response, for example.
However, I don't think that the waveguide structure can transmit the broadband time signal, because some of the frequency components are below the cut-off frequency.
Best regards,
Jaehoon
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Altair Employee