A novel simplified four-port scattering parameter model for design of four-pair twisted-pair cabling systems for local area networks

This paper presents a set of simplified equations based on a four-port scat tering model, which accurately characterizes four-pair twisted pair (eight- port) cabling systems for high-speed digital telecommunication local area n etworks. These equations are derived and simplified from two-stage cascaded four-port S-parameter matrices and verified experimentally. Excellent agre ement is obtained between the measurements and computational results when t he S-parameters of the cabling system components are known. These equations not only reduce the computation burdens in comparison with traditional met hods for transmission matrix computations, but also provide intuition of th e contributions of the S-parameters at each stage in the net crosstalk, ret urn loss, and insertion loss. Furthermore, these equations can be used to c ompute the component specifications when the system performance is specifie d, and to obtain the deembedded system characteristics by subtracting the k nown characteristics of adapters.