This paper introduces efficient Time-Domain techniques utilizing the Method of Moments to predict the electromagnetic behaviors of a communication system , invoking the coupling between these components. The system is composed of a parabolic antenna and a wire antenna. To render the problem manageable mathematically, an accurate Time-Domain Electric Field Integral Equations are formulated based on the boundary conditions for modeling the electromagnetic coupling between two antennas. Then, the Method of Moments is employed in both spatial and temporal domains to solve the TD-EFIE developed system. In the temporal domain, the unknown coefficients temporal component is represented as a linear combination of Laguerre functions. In space domain, we use an adequate hybrid mesh technique giving a stable result. The antennas are placed at various distances to observe the coupling impact. Transient responses of our system depending on the separation distance are evaluated and the transient current densities on each antenna are presented.