In recent LHCD experiments in JET, a large effort has been placed on improving the coupling of the Lower Hybrid waves in Optimised Shear plasmas, i.e. in conditions with internal transport barriers or H-modes. Good results have been obtained by using gas puffing with CD4 near the launcher. Results from coupling experiments have been compared with the SWAN coupling code, which has recently been extended to take into account the poloidal cut of the launcher mouth. The launcher mouth is composed of twelve rows of waveguides, all with different electrical lengths. By introducing the scattering matrices for all rows and calculating the resulting power splitting in the multijunctions, a more realistic model for the coupling is obtained.