Design of broadband transitions for substrate integrated circuits

We present a methodology to enhance bandwidth of the conductor backed coplanar waveguide-to-substrate integrated waveguide and microstrip-to-integrated waveguide transitions.Our approach exploits metalized vias partially protruding into substrate in the transition region as tuning elements. This allows us—for the considered type of transition—to increase useable bandwidth. Geometry parameters, including positions and sizes of extra vias, are adjusted using simulation-driven optimization procedure that exploits coarsely-discretized electromagnetic (EM) models of the transitions and the adaptively adjusted design specifications technique. The optimal design is obtained at a low-computational cost corresponding to a few high-fidelity EM simulations of the structure of interest (typically comparable with the number of design variables). Our technique is demonstrated with the X-band designs. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2942–2945, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26391