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    How to terminate microstrip line with Z0 = 50Ω?

    If I have a microstrip line with characteristic impedance of Z0 = 50Ω, how do I terminate it with 50Ω to ground? In the literature it's always assumed load exists but how do I implement it, ideally with non-radiating microstrip/vias. Would putting 50Ω RF resistor work too? Resistor would add extra cost so I'd like to avoid it.

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    Re: How to terminate microstrip line with Z0 = 50Ω?

    You terminate a 50 ohm line with a 50 ohm impedance, whether it's a resistor or an antenna or whatever. It's "always assumed a load exists" because why else would you have this line running off to nowhere??? Maybe you need to show us a schematic or something.



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    Re: How to terminate microstrip line with Z0 = 50Ω?

    Use 50 ohm resistor. Connect microstrip line to ground through this resistor.
    Ground:
    1) vias to ground or
    2) radial quarterwave stub
    second solution provides RF ground with arbitrary DC bias (no DC current through resistor). Although it has relatively narrow bandwidth.



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    Re: How to terminate microstrip line with Z0 = 50Ω?

    Quote Originally Posted by barry View Post
    You terminate a 50 ohm line with a 50 ohm impedance, whether it's a resistor or an antenna or whatever. It's "always assumed a load exists" because why else would you have this line running off to nowhere??? Maybe you need to show us a schematic or something.
    My schematic consists of unterminated 50Ω microstrip line and I need to terminate it somehow with non-radiating element so no antenna.

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    Quote Originally Posted by Georgy.Moshkin View Post
    Use 50 ohm resistor. Connect microstrip line to ground through this resistor.
    Ground:
    1) vias to ground or
    2) radial quarterwave stub
    second solution provides RF ground with arbitrary DC bias (no DC current through resistor). Although it has relatively narrow bandwidth.
    There's no other wave to match 50Ω line, other than using a resistor?



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    Re: How to terminate microstrip line with Z0 = 50Ω?

    If your bill of materials (BOM) have 100ohm resistors, you may use them in parallel and put radial stub as rf ground. Also you may go (by using stubs or series line) from some complex impedance point you have to the point on real axis of Smith chart, for example 180 ohm, and then terminate it to ground with 180 ohm (if it is near some value of BOM). You may check these ideas here: https://www.will-kelsey.com/smith_chart/



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