LNA Parallel RLC circuit

[Faizan shafi]

I am sharing the diagram of a Common emitter amplifier below. I want to have a understanding about Parallel rlc circuit at the output side. I wanna know how does my gain behave by changing the value of R.
in this current configuration . when I increase the value of R , the quality factor of my RL combination will decrease. also my gain will decrease and my bandwidth will increase. am I write about it so far?
now my question is what would happen if instead of attaching this resistor in series with the inductor, I attach it in parallel with the inductor. than what would happen if I increase or decrease the R value . what would be the advantages and disadvantage of doing it?

I don't have access to cadence or ads so I cant simulate this circuit. I have read about the series and parallel rlc circuits but I still don't have intuitive understanding of this. Can someone please clarify this confusion . the operating frequency is 40 Ghz. Thank you.

 

[ahsrabrifat]

At mm-wave frequencies like 40 GHz, parasitic capacitances and inductances become highly significant. A parallel RLC tank is often used as a load in tuned amplifiers to achieve a high gain at a narrow frequency band, making it ideal for narrowband applications such as oscillators or narrowband LNAs. On the other hand, if broadband operation is desired, using a series resistor offers better gain flatness and improved stability across a wider frequency range.

 

[Faizan shafi]

''using a series resistor offers better gain flatness and improved stability across a wider frequency range''. What would be the effect if place this resistor in parallel with the inductor. what purpose will it serve? How would main gian, bandwidth and Q will behave if I put this in parallel and change its value.

I was asked question in an interview that what would happen if you put this resistor in parallel , I could not give a satisfactory answer and It is bothering me. I just want to clarify this confusion.

 

[D.A.(Tony)Stewart]

The transistor is a current source with an output capacitance.

With this high R/L series ratio, the series resistor degrades any good chance of resonant gain.
Thus moving the R to a higher R shunt improves parallel Q and controls the damping better.