A new criterion for linear 2-port stability using a single geometrically derived parameter

A stability parameter, mu (S), is defined for linear two-port circuits using a geometrical approach. It is shown that mu >1 alone is necessary and sufficient for a circuit to be unconditionally stable. This single parameter can replace the dual Rollet (K>1) and auxiliary conditions for determining unconditional stability. The parameters K and mu are compared by discussing their implications in terms of mapping circles.>