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  1. #1
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    Circular polarization using coupler

    hello,
    i'm designing a patch antenna in hfss. in order to achieve circular polarization i'm planning to use a 90 degree hybrid coupler. Is it possible to create a 90 degree phase shift in orthogonal mode excitation in hfss without actually having to draw a coupler. thanks in advance.

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  2. #2
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    Re: Circular polarization using coupler

    Hi gayathrim,

    Yes, it is possible. Using either lumped ports or wave ports, you can set the sources excitation phase under "HFSS"->"Fields"->"Edit Sources...".

    Good luck!



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  3. #3
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    Re: Circular polarization using coupler

    you can set the sources excitation phase under "HFSS"->"Fields"->"Edit Sources...".
    I tried that. I used two lump ports positioned 90 degrees apart and sources changed to phase 0 and 90 respectively. however, i'm still not able to achieve an axial ratio vs frequency below 3 dB for resonating frequencies.



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    Re: Circular polarization using coupler

    Quote Originally Posted by gayathrim View Post
    i'm still not able to achieve an axial ratio vs frequency below 3 dB for resonating frequencies.
    Unfortunately, the issue is then your antenna, and not the excitation. Is it a circular patch?



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    Re: Circular polarization using coupler

    Quote Originally Posted by PlanarMetamaterials View Post
    Is it a circular patch?
    yes, it is. and the axial ratio at non resonating frequencies are less that 3 dB. but at resonating points, greater that 15dB.



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  6. #6
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    Re: Circular polarization using coupler

    Also, since there are two ports, which return loss should we consider? s11 or s22? or the resultant?



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