LNA for X band - is it possible ? transistor question

x band lna

I have to design a LNA. is it possible to have it for Xband bandwidth? or is it too large ?? another thing im concerned abt is the transistor. im doing the design using ADS and my ADS doesn;t have right models for transistors availble in market. im planning to use a agilent's ATF.

best lna, +x-band

ATF transistor is good for broadband amplifiers.
what do you mean by Xband bandwidth?
Why dont you enter your specifications here? Since It will be easy to understand your problem.

Re: LNA for X band

yup xband bandwidth. I don;t have spec as such but gain for 1 stage amplifier should be more than 5db and im not really concerned abt noise.

Re: LNA for X band

If you are not concern for noise figure then why you call it as LNA?
Be specific to the requirement.

Re: LNA for X band

as far as i know, ya can either design LNA for high gain or low noise which dependz on ur matching cicuit. therefore i would be designing my LNA for high gain... please correct me if im wrong

my concern is that if it is possible to design it with for Xband bandwidth. The transistor im planning to use is ATF34143. please advise me if i should use an alternative to it.

Re: LNA for X band

When you say Xband bandwidth, are you referring to the entire 7Ghz to 12.5Ghz spectrum?

Also, AFAIK, there is a reason why the first stage of signal chain is an LNA. According to Friis the noise of the entire chain is dominated by the first one, so it is always better to have low noise and high gain at the beginning and likewise linearity depends on the last stage.

LNA for X band

X band is a frequency band, defined IEEE radar bands, it covers the frequency range between 7 and 12.5 GHz.
Do you mean you want to design an LNA with 5.5 GHz bandwidth??? (between 7 and 12.5 GHz to cover all the X band???
I do not think that it would be hard to get the models for ATF34143 (at least an S parameter file with noise models), but I guess even it is possible to get nonlinear modell, like Statz or similar.
But ATF34143 is not the best choice for this frequency band. It would fit the best for S band.

If you follow the classic microwave design methodology. From the S parameters you put the noise and gain circles into the Smith chart and then you can make your trade off between the lowest noise and highest gain. Do not forget to check the stability (stability circles). You can find very comfortable design guide in ADS to do these.

And the basic design methodology based on the unilateral acrive device assumption, if your active devce is not unilateral you have to run several simulations to determine the optimum point.