Rollett-based single-parameter criteria for unconditional stability of linear two-ports

A family of linear two-port unconditional stability criteria is presented, which is specified in terms of a single necessary and sufficient condition involving a single parameters. Based on the commonly employed Rollett dual conditions, the stability parameters are derived in a simple and direct manner. The family is extended to include the single-parameters deduced from the dual Rollett and generalised auxiliary conditions. Straightforward proof of the new single-parameter condition implying μ₁>1 and vice versa is demonstrated. A comparison of the various criteria and μs is also illustrated and discussed. Three members of the single-parameter family are highlighted for being more advantageous than μ₁ in different aspects.