In this paper, we propose microstrip couplers loaded with a dielectric ridge for microwave integrated circuits and present theoretical analysis with the p-BEM. The numerical results show that by choosing appropriate dielectric constant and size of the dielectric ridge, a complete matching of the even and odd mode propagation velocities can be achieved, and thn high directivity coupler can be realized. The employed p-BEM is an suitable and efficient method to the analysis of such microwave components with multilayered media and dielectric ridge.