Overall stability factor of linear two-ports in terms of scattering parameters

Stability conditions for linear active two-ports in terms of classical two-port parameters, which include the terminations, have been derived earlier but the analogous result in terms of scattering parameters apparently is not known. It is shown that the stability condition is 1-|r/SUB G/s/SUB 11/|/SUP 2/-|r/SUB L/s/SUB 22/|/SUP 2/ + |r/SUB G/r/SUB L//spl Delta/|/SUP 2/>2|r/SUB G/r/SUB L/|.|s/SUB 12/s/SUB 21/| from which the overall stability factor is derived.