A two $$-$$ port network, shown in Fig. is described by the following equations:
$$\eqalign{ & {{\rm I}_1} = {Y_{11}}\,\,{E_1} + {Y_{12}}\,\,{E_2} \cr & {{\rm I}_2} = {Y_{21}}\,\,{E_1} + {Y_{22}}\,\,{E_2} \cr} $$

The admittance parameters, $${Y_{11}},\,\,{Y_{12}},\,\,{Y_{21}}$$ and $${Y_{22}}$$ for the network shown are

A two-port device is defined by the following pair of equations:
$${i_1} = 2{v_1} + {v_2}$$ and $${i_2} = {v_1} + {v_2}$$
Its impedance parameters $$\left( {{z_{11}},\,\,{z_{12}},\,\,{z_{21}},\,\,{z_{22}}} \right)$$ are given by

For the two port network shown in Fig. the admittance matrix is