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Zangetsu57
Joined: 23 Aug 2007
Posts: 32
Helped: 1
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 26 Jan 2009 21:20 pmc hfss |
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Hello everyone,
I am simulating a patch antenna that has H-plane symmetry. It is operating in the lowest mode. I get excellent impedance matching results for S11, but my radiation pattern (co-pol and x-pol) for both principal planes is not accurate when compared to the antenna simulated without the symmetry plane. Does anyone know why this might be? Is there something I need to do to tell HFSS to properly calculate the radiation pattern when using a symmetry plane?
Alternatively, if someone could link me or upload an example or tutorial as to how I should properly set up a symmetry plane, it would be greatly appreciated. Note that I DID use the impedance multiplier of 0.5 and set the port to solve Zpv.
Thank you in advance!
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26 Jan 2009 21:20 Ads |
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shahid78
Joined: 29 Jul 2006
Posts: 328
Helped: 28
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27 Jan 2009 12:15 pmc boundary symmetry |
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hi
well i havent used HFSS that much but all i can say is you need to make sure that your antenna is symmetric with respect to your chosen symmetry planes os more specifically w.r.t your excitation port
i hope it helps
regards
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Zangetsu57
Joined: 23 Aug 2007
Posts: 32
Helped: 1
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29 Jan 2009 21:29 hfss symmetry boundary conditions |
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Hello shahid78,
It understand that  . The patch antenna I am simulating has H-plane symmetry, so I was using a PMC symmetry plane to cut it in half.
It turns out that the scale was off on my graphs, as I had a -300 dB null at broadside on the x-pol at broadside for the H-plane, so that was distorting the graph. Silly me for not looking at the scale  . My H-plane co-pol and x-pol now match the results I got for the patch without the PMC boundary.
The E-plane, however, has a slight problem. The co-pol is fine, but the x-pol is computed to be zero when using the symmetry boundary. It is definitely not zero, and the original model predicts it to be, while small, about -60 dB. Then again, when the x-pol is this small, who cares, right? I have a feeling this might have to do with boundary conditions. Nevertheless, if there is a way around this, it would be nice to compute the x-pol for the E-plane as it may be significant for other designs. Does anyone have any ideas?
I attached my models here.
Thanks in advance!
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trichop
Joined: 31 Oct 2005
Posts: 11
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27 Oct 2009 4:52 Re: Symmetry Boundary (PMC/PEC) in HFSS - Pattern Problems |
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I checked the HFSS design you posted.
I don't see how with this antenna geometry you can utilize an E-plane for symmetry purposes ....
Electric field will always be parallel to the symmetry plane, so you can only use an H-plane symmetry plane.
Otherwise, I have misunderstood something.
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