Dual Gate MOSFET mixer

[I14R10]

Hello

I once came across dual gate MOSFET mixer schematics and equations, all in one pdf file. I don't know where that file is now. I have written some of the equations and schematics in my book, but I would like to have that pdf file again. If anybody has that file or something similar, can you please upload it here?

 

[erikl]

You don't need to ask the forum, again G00GLE is your friend.

 

[I14R10]

Unfortunately it's not in this case. I opened every one document from first few pages from google and it's not what I had before. In one document there is the same schematics but it's missing equations and descriptions.

 

[erikl]

Unfortunately it's not in this case. ... In one document there is the same schematics but it's missing equations and descriptions.

Sorry for that. In this case it would perhaps be helpful if you'd show this same schematics (or provide the link) and tell which equations (for what) you're missing.

 

[Bilal_Ahm]

please check history of explorer. which one you are using?

 

[I14R10]

Here it is - page 9 https://www.qsl.net/va3iul/RF Mixers/RF_Mixers.pdf, schematics on the left. I was wondering about the inductance in the MOSFET drain. How do we choose that inductance? It says, in the text in that pdf that we should choose L and C to have high impedance. That means large inductance, right? Do we just say - let's make this one 5mH and calculate capacitor value from that?

And checking history won't help because I downloaded that pdf about 1 year ago. It's really not that important, it's just very useful.

 

[FvM]

High impedance of a LC circuit means primarly tuned to resonance, characteristic impedance √(L/C) according to the intended IF bandwidth.

 

[kemiyun]

What is said above + you are also limited by the Q factors of those devices for highest achievable impedance. So if a higher Q available at a different value I'd go for that and choose C based on that value because in vlsi design you don't get high Q for any value of L. I'm not very experienced in discrete circuits though maybe there would be other considerations.