  The resolution of the Green's function for obtaining the electrostatic
potential generated by the charges located in the dielectric layer of a
rectangular waveguide requires efficient integration techniques. Due to the
characteristics and the oscillatory nature of the function to be integrated,
the use of the Filon's method together with a convergence analysis is adequate.
However, the application of this numerical integration technique can lead to
numerical instabilities in the result. For this reason, in this research work
we have presented two different methods to deal with these numerical errors of
integration: SSA/MSSA and GPR. In this way it is possible to clean the
electrostatic potential avoiding subsequent errors in the calculation of the
electrostatic field.
