A substrate integrated guide which allows the propagation of both TEm0 and TE0n modes is presented, the Extended Substrate Integrated Waveguide (ESIW). Its structure combines the working principles of SIWs and SINRD guides. While the performances of the ESIW with TEm0 modes are the same as conventional SIWs, they are better than SINRD guides concerning TE0n-like modes. In addition, a novel slotline-based excitation is proposed to launch the TE(01)mode in the ESIW. This solution alleviates some of the problems encountered in current structures used to excite TE01-like modes, e.g., spurious mode excitation or complicated manufacturing designs. Measurements of a slotline fed ESIW are presented validating the proposed concepts.