Transient electromagnetic scattering from thin wire: MOM Code

Hi,

I want to calculate transient current at the center of a thin wire by using MoM in time domain.
I implement the formulas detailed in the following book Time Domain Electromagnetics pages 52? 55 for calculate the transient current.
The source is given by a Gaussian pulse (page 21).
My problem is: I find as a result a sinusoidal current and not transient current!
Is the problem in my code?
Thank you in advance

I think you should post your code...