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help needed in designing LNA X-band

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bee5906

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hello.im a student and i need help to design my LNA in X-band.step by step.thx
 

tony_lth

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What's your requirements? Gain? NF? etc.
You can use SmithChart for design.
 

bee5906

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What's your requirements? Gain? NF? etc.
You can use SmithChart for design.

um.i'm not pretty sure.but if i'm using the atf36163 model,do i have to follow the requirements as give, like noise figure = 1dB, gain=9.4dB?and how do i get it to operate at 10Ghz?i'm really clueless about this.but thanks for your help.
 

rfmw

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If you had already decided which transistor you'll use, then the best performance figures like NF and gain are alredy defined. So you should design the LNA to achieve these figures (probably the most important is the lowest NF). See circuit examples in datasheets and start your matching from that. Don't forget about the stability. Use low-loss substrates, like Rogers duroid. Tell us more where can we help you with, since your question is too general. If this is your first time with RF design, you should definitely start with a lower frequency. You could make an x-band amplifier and also an oscillator in Ka-band at the same time, even without knowing it.
 

Microwave123

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Hi bee5906,

Here is a general approach.

1) Plot Stability Circles, NF circles, and gain circles on the Smith Chart.
2) Match input for NF and stability.
3) Match output for gain and stability.
4) Simulate your circuit and make sure you have the basic functionality over a narrow band.
5) Run optimization routine to obtain desired BW, NF, match, reverse isolation (low S12), and gain etc...

Hope this helps,

Microwave123
 
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