how to fix undefined function or method problem for input arguments of type 'double'

I tried to carry out this in matlab and it gave me this error message :

??? Undefined function or method 's2rlgc' for input arguments of type 'double'.

Please how do i fix this problem.

s_11 = 0.000249791883190134-9.42320545953709e-005i;
s_12 = 0.999250283783862-0.000219770154524734i;
s_21 = 0.999250283783863-0.000219770154524756i;
s_22 = 0.000249791883190079-9.42320545953931e-005i;
s_params = [s_11,s_12;s_21,s_22];
% Specify the length, frequency of operation, and impedance of the transmission line
length = 1e-3;
freq = 1e9;
z0 = 50;
% Convert from s-parameters to rlgc-parameters
rlgc_params = s2rlgc(s_params,length,freq,z0);
display(rlgc_params)

Answer 1

[Walter Roberson]

s2rlgc requires the RF Toolbox be installed and licensed.