tjuby
Junior Member level 1
Greetings, I recently posted a topic in the simulation board about stability calculations and smith chart plots. This is a relating question, but more general.
In my design that I'm trying to do some stability calculations on I have 3 (surface mount technology) LNAs in a cascade.
It looks approximately like this:
input --- LNA --- LNA --- LNA --- output network.
(you your imagination and envision it as a block diagram
)
My question is this:
Does anyone know if the theory of Rollets stability conditions (with auxilliary condition) also apply for a two-port network where there are several amplifiers? The theory given in "Microwave Engineering" by David M. Pozar does not specify this very clearly. He only describes a two-port network with one amplifier in it.
By my reasoning i think that it probably would count if there were more than one amplifier too, because the analysis of stability utilizes S parameters, which I simulate in CST Design Studio. These parameters should complete describe the reflections and gains of the system, so if I use the S paramaters from the simulation results, that should be enough to do the stability analyzis.
I am not sure though and I suspect such an analysis would be more complicated than that.
If anyone has any experience with such stability analysis and could direct me to papers or articles that talk about stability analysis of two-port systems with several amplifiers, or would like to share some knowledge about this I would be very very greatfull!
Thank you for your attention,
Alexander
In my design that I'm trying to do some stability calculations on I have 3 (surface mount technology) LNAs in a cascade.
It looks approximately like this:
input --- LNA --- LNA --- LNA --- output network.
(you your imagination and envision it as a block diagram
)My question is this:
Does anyone know if the theory of Rollets stability conditions (with auxilliary condition) also apply for a two-port network where there are several amplifiers? The theory given in "Microwave Engineering" by David M. Pozar does not specify this very clearly. He only describes a two-port network with one amplifier in it.
By my reasoning i think that it probably would count if there were more than one amplifier too, because the analysis of stability utilizes S parameters, which I simulate in CST Design Studio. These parameters should complete describe the reflections and gains of the system, so if I use the S paramaters from the simulation results, that should be enough to do the stability analyzis.
I am not sure though and I suspect such an analysis would be more complicated than that.
If anyone has any experience with such stability analysis and could direct me to papers or articles that talk about stability analysis of two-port systems with several amplifiers, or would like to share some knowledge about this I would be very very greatfull!
Thank you for your attention,
Alexander
