How to increase gain
My requirement is 10dB gain for input of -20dBm power. I am getting 4dB gain for the same input power. I am using ADS TOM Model. Please guide me what parameters can be changed to get my desired gain.
What's your freq and modulation?
What's the other requirements? such as S12, harmonics, OIP3, etc?
My frequency of operation is 12GHz.
I have done DC analysis and obtained Idss = 60mA at Vgs=-1.27V and Vds =2 V.
and now m working on S parameters . My target is to increase gain(s21) up to 11 dB ,presently is 4dB.
other requiremets are
S11:-6 (satisfied) dB
S12: -19dB required ,-10 dB received.
S22:-11dB (required) ,-5dB received
I guess my matching is not proper. Please help me out .
Which tom model parameter can give me more gain when changed?
Model cannot give more gain, a good matching will give you more gain in your case.Since you're working on a single frequency, do these matching well and see the results.
There is no better model or something.There is better designed circuit and worse designed circuit.
Thank you for your reply.
As per your guidance ,there is no change required in any of the model parameters such as gamma,alpha,cgs,cgd..etc. to increase gain , is it ?
A good matching means I have to connect an input /output matching network to this model ? How should I proceed further please guide me. Please suggest me some books so that I can refer it and move forward.
All those parameters have already been extracted and some of them bias dependent so you cannot play with them freely.In order to increase the gain, Gm should also be increased and it's easy it to increase by increasing drain current .. Right ? But the other bias dependent parameters will also move left and right...
Therefore the existing flexibility is not as wide as manipulating a matching circuit.
As a parctical rule, the transistor bias condition is choosen regarding to sufficient gain and less nonlinearity then this bias point is fixed.After that you realize proper input and output matching circuits to get this ideal gain ( Gmax and/or GMSG)
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Thankyou Bigboss for your valuable suggestions.
A datasheet of cfy6708 Hemt device has S parameters values.With the help of Tom model i want to gain those parameters.So in that case,the model parameters will only change and S parameters are achieved ? or input /output matching networking along with biasing network is also added to tom model for those S parameters to achieve?
What is the actual procedure?
When any reference datasheet is given and we have to obtain the S parameters of that datasheet from our nonlinear MODEL, WHAT IS THE ACTUAL PROCEDURE?
Please solve my confusion.