[en] Compact Lower Hybrid launching structures are described in the present paper using a waveguide array in tandem with an E plane junction, phase shifters or passive waveguides. It can be shown that coupling between the waveguide apertures and the E junction plane does not perturb the N parallel wavenumber spectrum (parallel to the toroidal magnetic field) required for the slow wave penetration into the plasma provided that the electric length between these discontuities is sufficient for the evanescence of upper parasitic modes. Numerical results are given for the alternate active and passive waveguide array first proposed by MOTLEY and HOOKE and for a new compact heating and current drive LH antenna