Distance from unconditional stability boundary of a two-port network

Many parameters are available to show if a linear two-port network is unconditionally stable or not, but none of them shows the distance from the boundary of unconditional stability in the scattering parameter space. Here, the boundary of unconditional stability is demonstrated as hypersurfaces and the distance of the network´s parameters from this boundary for the absolutely stable condition is derived using new single stability parameters. The boundary is shown in the S- and Y-dimensions (parameters of scattering and immittance matrices). The unconditional stability safety factor is also introduced to determine the distance from the boundary of unconditional stability for the absolutely stable condition, using scattering parameters. Examples and applications are also demonstrated.