In this paper, applying the REC model which characterizes the coupling between the radiating edges to two coupled rectangular microstrip patch antenna, we obtain scattering parameters $mid$ $S_{11}$ $mid$ and $mid$ $S_{12}$ $mid$for the various coupling separations, Se=0.5mm, 1.0mm, 1.5mm, and 2.0mm, The calculated values are compared with the measured values. For the rectangular microstrip patch antenna with a parasitic element which is gap-coupled to the radiating edges of the rectangular patch, calculated return losses using the REC model are compared with measrued values. Here, the each microstrip antenna is fed by a 50 microstrip line. The purpose of the paper is to compare a 50$Omega$ microstrip line fed case with a coaxial fed case treated in Ref.