Documentation 
Convert Sparameters to RLGC transmission line parameters
rlgc_params = s2rlgc(s_params,length,freq,z0)
rlgc_params = s2rlgc(s_params,length,freq)
rlgc_params = s2rlgc(s_params,length,freq,z0) transforms multiport Sparameter data into a frequencydomain representation of an RLGC transmission line.
rlgc_params = s2rlgc(s_params,length,freq) transforms multiport Sparameter data into RLGC transmission line parameters using a reference impedance of 50 Ω.
rlgc_params 
The output rlgc_params is structure whose fields are NbyNbyM arrays of transmission line parameters. Each of the M NbyN matrices correspond to a frequency in the input vector freq.

The following figure illustrates the RLGC transmission line model.
The representation consists of:
The distributed resistance, R, of the conductors, represented by a series resistor.
The distributed inductance, L, of the conductors, represented by a series inductor.
The distributed conductance, G, between the two conductors, represented by a shunt resistor.
The distributed capacitance, C, between the two conductors, represented by a shunt capacitor.
RLGC component units are all per unit length Δx.
Convert Sparameters to RLGC transmission line parameters:
s_11 = 0.000249791883190134  9.42320545953709e005i; s_12 = 0.999250283783862  0.000219770154524734i; s_21 = 0.999250283783863  0.000219770154524756i; s_22 = 0.000249791883190079  9.42320545953931e005i; s_params = [s_11,s_12; s_21,s_22]; length = 1e3; freq = 1e9; z0 = 50; rlgc_params = s2rlgc(s_params,length,freq,z0)
Degerstrom, M.J., B.K. Gilbert, and E.S. Daniel. "Accurate resistance, inductance, capacitance, and conductance (RLCG) from uniform transmission line measurements." Electrical Performance of Electronic Packaging,. IEEEEPEP, 18th Conference, 27–29 October 2008, pp. 77–80.
Sampath, M.K. "On addressing the practical issues in the extraction of RLGC parameters for lossy multiconductor transmission lines using Sparameter models." Electrical Performance of Electronic Packaging,. IEEEEPEP, 18th Conference, 27–29 October 2008, pp. 259–262.