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Waveguide S parameter calculation, boundary mode analysis problem
Posted Jul 13, 2011, 11:20 a.m. EDT RF & Microwave Engineering, Results & Visualization Version 3.5a 3 Replies
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My task is to analyze the resonance property of a 3D optical waveguide cavity. As the first step, I am now following the "waveguide adapter" model to calculate the S parameters (reflection and transmission) of a straight waveguide (see my mph file attached).
My problem is that the eigenmode calculated by the "boundary mode analysis" looks strange, and the calculated effective mode index also largely deviates from the one obtained by 2D mode analysis. It is also interesting to see that the calculated S21 (transmission) is close to 0 dB, which is reasonable, at the frequency that I set for boundary mode analysis. But S21 will exceed 0 dB as the frequency becomes smaller. So, anything stupid in the model? Something wrong with the boundary condition setting?
Any comments will be very appreciated !!
Z
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I finally found the problem, the boundary mode analysis should be applied to all the sections of the input facet. I previously only apply the analysis in the waveguide core section.
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Great ! :)