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S11 of the Front-end (Read 67 times)
YYou
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S11 of the Front-end
Mar 02nd, 2009, 1:01pm
 
Dear all,

I am testing my front-end. With off-chip matching components, the input can be matched at the operating frequency. But at the same time I always see another notch at twice the operating frequency, which is not there in simulation.

Can anyone give some suggestions how this could happen ?

Thanks so much ,

Yyou
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YYou
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Re: S11 of the Front-end
Reply #1 - Mar 2nd, 2009, 2:18pm
 
Just add some basic information:
1. the LNA is single-ended.
2. The matching is through inductive-degenerated structure.
3. Gate inductor is implemented off-chip.

Thanks,

Yyou
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pancho_hideboo
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Re: S11 of the Front-end
Reply #2 - Mar 2nd, 2009, 8:03pm
 
YYou wrote on Mar 2nd, 2009, 1:01pm:
I am testing my front-end. With off-chip matching components, the input can be matched at the operating frequency.
But at the same time I always see another notch at twice the operating frequency, which is not there in simulation.
Can anyone give some suggestions how this could happen ?

Maybe due to parasitic effects of board and package.

Show me smith charts of input impedance with off-chip matching and without off-chip matching.
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« Last Edit: Mar 3rd, 2009, 4:30am by pancho_hideboo »  
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