In this paper, the analysis of the multipath characteristics of time modulated arrays (TMAs) is presented in a theoretical framework. In particular, the simple two-way propagation concept of the TMA on a perfectly conducting ground plane is investigated by evaluating horizontal and vertical polarization situations. Due to the time difference of the electromagnetic fields at the source and observation point, the effect of the propagation delay of TMAs in the far-field is taken into account. Moreover, the effect of the ground plane on critical parameters of TMAs such as radiation pattern, max sideband level (SBL), total power (P-SR) associated with harmonic radiation that brings power loss and the efficiency (eta) of the system consisting of feed network and harmonic efficiency are investigated for linear TMA positioned parallel and perpendicular to the ground plane. As a result, the power loss expression for the infinite ground plane is revised and it is shown that the ground plane changes the total efficiency.