A Wideband Millimeter-Wave SIW-to-RWG Transition for Thin Single Layer Substrates with Thick Metal Cladding

In this paper, a vertical transition from substrate integrated waveguide (SIW) to rectangular waveguide (RWG) in a single layer thin substrate PCB with thick metal cladding is proposed. A dual resonance cavity in SIW and a stepped impedance transformer in the RWG allow matching of more than 25 % of relative bandwidth at 94 GHz center frequency. 3D-electromagnetic simulations are used for optimization and compared to measured results to confirm the results and the functionality of the transition. Within the measured frequency range of 82 to 107 GHz, the single transitions measurement results show less than 0.7 dB insertion loss and more than 12 dB return loss.