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Power that is sent through a scattering boundary condition
Posted Feb 22, 2018, 5:28 a.m. EST RF & Microwave Engineering, Wave Optics, General 1 Reply
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Hey everyone!
I am trying to obtain a transmission vs wavelength plot using Wave Optics Module and using the model shown in the attached image ("Structure"), which represents a unit cell of a photonic crystal. I send a wave using a scattering boundary condition at the top of the structure (whose parameters can be seen in the attached image "Scattering boundary conditions"). There is a block PML on the bottom of the structure and Floquet periodic boundary conditions all around.
I measure the Power outflow, time average (W) using ewfd.nPoav on the top surface of the PML (bellow the photonic crystal structure; surface integral) and the results I obtain (in terms of the shape of the transmitted power vs wavelength) are exactly the same as the ones shown in several research papers on photonic crystals (obtained by FDTD). The problem is that I need to normalize such transmission power values by the inputted power in order to obtain the actual transmission (a value ranging from 0 to 1) - but I can't figure out how to know the power I am inputting.
I can't use ewfd.nPoav on surfaces above the structure because that will give me the reflected power.
Does anybody know how I should proceed?
Thank you so much! :)
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Since the same problem is also shown in other COMSOL Forum's post and no reply was also given to it (before the discussion was closed), I will answer here how I managed to solve the problem.
Although it is definitely not the best method and it still requires some computational power and time, I verified the inputted power by removing the PhC from the model and simulating without it. Afterwards, I applied ewfd.nPoav to the same boundary condition to obtained the desired value.