A Broadband Stepped Configuration of Substrate Integrated Waveguide Vertical Transition Structure

This brief proposes a novel broadband vertical transition structure based on the substrate integrated waveguide (SIW)
$TE_{10}$
mode of multilayer printed circuit boards (PCBs). For the first time, broadband low-loss vertical transmission is achieved by loading double broadside coupled-coplanar striplines (DBC-CPS) structures within the stepped configuration of the SIW structure. It solves the problem of high loss associated with conventional SIW gap-coupling transmission. The equivalent circuit model is established based on quasi-static analysis method, and the electromagnetic field analysis results are given. The final test results show that the new structure operates at 5.5~8.2 GHz with insertion loss of 1.2~2.2 dB and 3-dB fractional bandwidth (FBW) of 44%.