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  1. #1
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    Is needed impedance matching for mixer diodes?

    Hello,

    I would like to design rat-race mixer with 2 diodes. There is a lot of materials, but I didn't read any stuff around matching diodes.

    Is it needed or not? I saw both types - 1, diode is on rat race without any microstripe line 2, diode is shifted from rat-race with some matching.

    Does it depend on biasing, LO power, RF power or some characteristical values of diode?

    Thank you for your help.

    - - - Updated - - -

    Click image for larger version. 

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ID:	156591 Here is some example for first type - on rat-race and here is second type with matching Click image for larger version. 

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ID:	156592.

    I would like to design it for 24 GHz - but is there something different for 2,4GHz; 5,8Ghz or 24GHz from this point of view?

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  2. #2
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    Re: Is needed impedance matching for mixer diodes?

    Matching, if is well done and tuned, will decrease the insertion loss of the mixer.
    If is not designed well the mixer may have higher insertion loss compared with no matching at all.
    The matching circuit will make the mixer narrowband, when with no matching the mixer has broader bandwidth.



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  3. #3
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    Re: Is needed impedance matching for mixer diodes?

    Thank you vfone. Do you know how to simulate diode in CST? Problem is I have 2 spice files - for diode and for package, how to make one file from that?

    Thank you very much.



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