Observation Area Analysis, Field Distributions, dB

[Miguel Bernardo Trindade Simões da Silva Rosa]

Good evening,

Could someone explain to me what is the advantage of using decibels in the Observation Area Analysis, in DFT, for calculating the field distributions?

It would be a very good help if someone could explain this to me.

Best regards,

Miguel Simões Rosa

[Miguel Bernardo Trindade Simões da Silva Rosa]

Good evening,

Could someone help me?

Regards,

Miguel Simões Rosa

Instituto Superior Técnico

[Md.Adnan Riaz]

Hi Miguel. I am sorry that I can’t help you about this.Can you please tell me what will be the units of DFT Ey for the image view and plane view that I have attached here?

[Miguel Bernardo Trindade Simões da Silva Rosa]

Hello! It’s V/m. How did you put that scale bar?

[Md.Adnan Riaz]

Thank you Miguel. Is it V/m also for DFT Ey(first graph)? I didn’t add the scale, it came with OptiFDTD itself. Miguel I have some other questions about power calculation, can you help me?

[Miguel Bernardo Trindade Simões da Silva Rosa]

Yes ask, no problem,. If I could I will try to answer.

[Damian Marek]

Decibels allow you to see a larger range of values than a normal scale. I generally stick with the linear scale for observation areas, but say you want to see some feature which is much smaller than the main part of the graph. It will show up clearer with a dB scale.

[Miguel Bernardo Trindade Simões da Silva Rosa]

Thanks very much Damien! It was a good help! Best regards

[Md.Adnan Riaz]

Is there any way to calculate the input and output power to find the power loss during propagation? I have tried to find it using observation point but I could not understand what the Y axis indicates. Is it power (dB) VS wavelength?

[Miguel Bernardo Trindade Simões da Silva Rosa]

Sorry for the late Adnan! I usually work with the observation areas. I think that in the Y is the power normalized and in the decibel scale, I have that idea because of the options that you have selected. Why you don’t use a observation area?

[Md.Adnan Riaz]

Its fine Miguel no problem! Ok I have just simulate one of the design using observation area. Can you tell me by selecting which option I can find the propagation loss or transmission loss? Please check the attachment.

[Miguel Bernardo Trindade Simões da Silva Rosa]

Hello! If you the field distribution select the wavelength that you desire and select update graph. For the power, go to Power Spectrum, I think that is this that you want. Write the minimum and maximum wavelengths, select the normalize with and finally calculate. Don’t choose too much sample points, it takes time.

[Md.Adnan Riaz]

Hi Miguel! Thank you so much for your reply. I have tried according to your suggestion and it worked. Miguel you explain me the graph that I have attached here? Here the observation point1 and point2 refer to starting and ending point of the waveguide (input and output) respectively.I got higher value for ouput compared to input, is this possible? If so, what is the explanation according to your point of view? Thanks in advance.

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