The task is to design a amplifier for maximum gain, which means conjugate matching. The S-parameters at different frequencies are as follows
Now for 1GHz $$K<1 \text{ and } \left|\Delta\right|<1$$ so the amplifier is not unconditionally stable. Here is a plot of the Load and Source stability circles
Using the simultaneous match equations, my value for \$Γ_L = 1∠124.39^\circ\$. Now this is obviously inside the Load stability circle. My question is then, how is the amplifier stable? The solution gives the answer as that the amplifier is stable.
