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  1. #1
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    Doherty power amplifier

    Hi,
    Trying to design a doherty power amplifier little confusion on choosing bias point for class AB and class C power amplifier.Do we choose the bias point based on the vgs and Id curve obtained from the curve tracer in ADS?

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  2. #2
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    Re: Doherty power amplifier

    Of course you should know the bias point for both C-Class and AB-Class.In order to decide these OPs, you have to know DC IV Characteristics of the Transistors.



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    Re: Doherty power amplifier

    Quote Originally Posted by BigBoss View Post
    Of course you should know the bias point for both C-Class and AB-Class.In order to decide these OPs, you have to know DC IV Characteristics of the Transistors.
    I understand that but I am having confusion choosing the bias point. while reading a few papers I saw a different process for chooisng the bias I attached the figure for two approches and would like to know which is correct. Thanks.

    Click image for larger version. 

Name:	figureIdvsVgs.png 
Views:	4 
Size:	86.9 KB 
ID:	152495



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  4. #4
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    Doherty offset lines

    Hi,

    I am trying to design a Doherty power amplifier,can anyone explain how to design the offset lines. I used (z=50,90 degree) and (z=35.35, 90 degree) transmission lines as combiner circuit to 50 ohm load.I am not able to obtain desired efficiency at back off. Please help.



    Thanks.



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