“…Consequently, an effective transition between SIW and WR-28 standard waveguide is required. There were two types of configurations have been developed, a right-angle where the axes of both waveguides are perpendicular [3,4,5,6,7,8] and an in-line configuration where the both waveguides are collinear [9,10,11,12]. The rightangle transitions employed a coupling aperture cut in the broad wall of SIW to ensure the matching between both waveguides.…”