A Novel Wideband Transition between Waveguide and SIW

Based on a linearly tapered antipodal finline, a novel low-loss wideband transition between waveguide and substrate integrated waveguide (SIW) is discussed. Results show that a low insertion loss (1.2-2.1dB) and a return loss better than 15dB across the entire Ka-band are obtained for a back-to-back transition structure.