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  1. #1
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    SMT DC Block for 13GHz

    Hi
    i'm looking for simple DC block SMT capacitor for e.g. 0402 or 0603 for 13GHz
    i mean that at this frequency the Capacitor impadance will still be capacitive and not inductive and will allow to ac couple the signal.
    till now i haven't found such becuase not all datasheets have impedance vs. frequency graph.

    would be glad if someone here could assist
    Arye
    Thanks
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    A.N

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    Re: SMT DC Block for 13GHz

    There are capacitors specially designed for this application, e.g. http://atceramics.com/applications/3...and-Capacitors



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  3. #3
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    Re: SMT DC Block for 13GHz

    thanks a lot, i also saw this kind of ATC capacitors but i wasn't sure that i see the right parameter in datasheet that allows me to be sure that its is still capacitor without inductence @13GHz , on what parameter graph i need to look at , to be sure that the capacitor will still be capacitor ?
    Thanks
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    Re: SMT DC Block for 13GHz

    They only give S21 magnitude, thus you don't know if the series impedance is capacitive or not. But this doesn't actually matter if it's small enough.



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    Re: SMT DC Block for 13GHz

    But if i have an RF signal with Bandwidth (sorry for not mentioning it before, i only now saw that there is a bandwidth)
    so if its capacitive or inductive impedance it may influence on my Band Flatness thus i want to be sure it will have only capacitive impednace and operate as dc block while being SMT small component (dc block capacitor)
    Thanks
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    A.N



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    Re: SMT DC Block for 13GHz

    Quote Originally Posted by levnu View Post
    But if i have an RF signal with Bandwidth (sorry for not mentioning it before, i only now saw that there is a bandwidth)
    so if its capacitive or inductive impedance it may influence on my Band Flatness thus i want to be sure it will have only capacitive impednace and operate as dc block while being SMT small component (dc block capacitor)
    You misunderstand the concept. The cap is used to block DC. For the RF signal itself, you want an impedance that is as small as possible. The sign of that series +/-jX doesn't matter, what matters is the magnitude.



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    Re: SMT DC Block for 13GHz

    Band flatness can be clearly derived from S21, what's your exact problem?



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  8. #8
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    Re: SMT DC Block for 13GHz

    thanks
    it seems that i have just got confused with my self,
    i only wanted to ac couple (by using simple capacitors) specific VVA IC input/output that requires DC block at its input and output
    VVA around 13GHz signal BW 0.7GHz
    i dont know how to be sure that some capactior will be suitable or not.
    now i will look only on S21
    Thanks
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    A.N



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