I learn that K=(1-|s11|²-|s22|²+|Δ|²)/(2|s21||s12|)>1 and|Δ|>1 then LNA or PA will be stable.
is there any software can simulate and calculate the K?
can i use a network analyzer to test a LNA or PA'K factor?or there is other way?
thanks for any advice
ADS has a built in tool for checking it ( K and MU ).. not sure about network analyzer!!!
if unstable put a 1 ohm or 2 ohm resistance in the base of transistor.. if not increase the resistance ..
there are ways but it is the most easy one!!!
Obtain your s-parameter by measurements and make compute your K factor for instance in Excel or Matlab...
Some VNA's can calculate K-factors.Almost all commercially available simulators such as AWR,ADS and the others can calculate K-factor.