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Use of Ports to calculate the Transmittance and Reflectance of an array of resonators

Posted 21 févr. 2013, 09:34 UTC−5 RF & Microwave Engineering Version 4.2a, Version 4.3a 4 Replies

Ramses V. Martinez
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Hi everybody,

+Problem: I want to simulate an square array of gold nanorings, in order to get the graphs for the transmittance and the reflectance and find the resonant frequency.

+My first approach:
-One box (Air) with one ring in the center (Au).
-A regular Port is ON on the top of the box (E=1,0,0) so it launches plane waves along Z. The waves will pass through the hole of the ring.
-Another regular Port is OFF on the bottom part of the box.
-The lateral walls of the box of Air parallel to X are PMC the perpendicular ones are PEC.
-I made a 1DPlot of
Reflectance= abs(emw.S11)^2
and
Transmittance=abs(emw.S21)^2
versus frequency

+Questions:
-How tall should I make my box to get an accurate result?

-I've read some post about people simulating similar structures by adding two PMLs (one at the top, one at the bottom of the box of Air). These people use a surface current to generate the plane waves. Is this method better/more accurate than what I'm doing?

Thanks in advance for your help!

Ramses
4 Replies Last Post 22 févr. 2013, 22:36 UTC−5
Alexander Kuznetsov
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Posted: 1 decade ago 22 févr. 2013, 13:22 UTC−5
no, the way you are doing it is better. I'd change PEC and PMC boundary conditions to periodic (floquet) BC. Otherwise, your simulations are correct only for normal incidence and one polarization.
no, the way you are doing it is better. I'd change PEC and PMC boundary conditions to periodic (floquet) BC. Otherwise, your simulations are correct only for normal incidence and one polarization.
Alexander Kuznetsov
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Posted: 1 decade ago 22 févr. 2013, 13:24 UTC−5
regarding the height, start with something small and increase. You solution should converge to certain value. Stop when it gets close enough to that value.
regarding the height, start with something small and increase. You solution should converge to certain value. Stop when it gets close enough to that value.
Ramses V. Martinez
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Posted: 1 decade ago 22 févr. 2013, 22:21 UTC−5

regarding the height, start with something small and increase. You solution should converge to certain value. Stop when it gets close enough to that value.



I've made several simulations today and I can say that a good value for the height of the box is 3 microns (considering that the thickness of the nanostructures is 100nm). This means that the distance to the ports from the center of the nanostructure is 1.5 microns.

Thank you very much for your advice!

Ramses
[QUOTE] regarding the height, start with something small and increase. You solution should converge to certain value. Stop when it gets close enough to that value. [/QUOTE] I've made several simulations today and I can say that a good value for the height of the box is 3 microns (considering that the thickness of the nanostructures is 100nm). This means that the distance to the ports from the center of the nanostructure is 1.5 microns. Thank you very much for your advice! Ramses
Ramses V. Martinez
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Posted: 1 decade ago 22 févr. 2013, 22:36 UTC−5

no, the way you are doing it is better. I'd change PEC and PMC boundary conditions to periodic (floquet) BC. Otherwise, your simulations are correct only for normal incidence and one polarization.


Great! I'm so happy :)

I appreciate a lot the tip for the boundary conditions. Unfortunately, I've been investigating this and I am stuck here:

I create a "Periodic Condition"--> Type: "Floquet Periodicity"-->Enter: "kF for Floquet periodicity"

If the plane waves that my port at the top generates travel along Z with E=(1,0,0):
+What should I enter as kF for the boundaries parallel to X (currently set as PMC)?
+What should I enter as kF for the boundaries perpendicular to X (currently PEC)?

Than you very much in advance!

Ramses
[QUOTE] no, the way you are doing it is better. I'd change PEC and PMC boundary conditions to periodic (floquet) BC. Otherwise, your simulations are correct only for normal incidence and one polarization. [/QUOTE] Great! I'm so happy :) I appreciate a lot the tip for the boundary conditions. Unfortunately, I've been investigating this and I am stuck here: I create a "Periodic Condition"--> Type: "Floquet Periodicity"-->Enter: "kF for Floquet periodicity" If the plane waves that my port at the top generates travel along Z with E=(1,0,0): +What should I enter as kF for the boundaries parallel to X (currently set as PMC)? +What should I enter as kF for the boundaries perpendicular to X (currently PEC)? Than you very much in advance! Ramses

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