A junction for connecting two waveguides (101, 103) having substantially a 90-degree angular offset between longitudinal symmetry axes of their cross-sections, said junction comprising a first interface (102) and a second interface (104) for connecting said waveguides (101, 103), and further comprising at least a first transformer section (202) and a second transformer section (206), both having cross-sections of substantially rectangular shape, and both having said 90-degree angular offset between longitudinal symmetry axes of their cross-sections, wherein the first and the second transformer sections (202 and 206) are connected in a way that a T-shape connection is formed and the first transformer section (202) has a first protruded ridge (204) on its broad wall (210) and the second transformer section (206) has a second protruded ridge (208) on its broad wall (212), wherein the broad wall (212) with the second ridge (208) is connected to the top narrow wall of the first transformer section (202) and the ridges (204 and 208) are so located that they overlap.