The Smith Chart is a mapping between reflection coefficient and normalized
impedance characterized by a pair of equations:

      z - 1
Gamma = -----
      z + 1

   Gamma + 1
z = --------
   1 - Gamma

The impedance matching problem is mainly finding the

z

that having reflection coefficient

Gamma  = ℜ  + jℑ
   z    z      z

satisfies:

           2    2        2
          ℜ  + ℑ   = Gamma
           z    z
       1   2    2    1
( ℜ  - - )   + ℑ   = -
   z   2        z    4

Using some algebra it is easy to find out

        2
ℜ  = Gamma
z

,

       _____________
    _ |    2       4
ℑ  =  \|Gamma  - Gamma
z

Now, we already know that the real component of

z

is

1

Then the imaginary part of the two matching impedance would be:

           2ℑ
             z
+/- -----------------
     2          2
    ℜ  - 2ℜ  + ℑ  + 1
     z     z    z