A Broadband Transition From Ridge Gap Waveguide to Microstrip Using Suspended Line Coupling

Abstract

This letter proposes an inline, ultrawideband, and low loss transition from microstrip line (MSL) to ridge gap waveguide (RGW). An efficient conversion between operational mode of RGW and the quasi-TEM mode of MSL is presented by using suspended line patch as a bridge. Furthermore, the effect of loading a capacitive iris on the transition matching performance is studied and a methodology to tune the transition bandwidth is proposed. In order to validate the presented solution, a back-to-back transition prototype is developed and investigated experimentally. The measured results show an insertion and return loss of 0.4 and 15 dB, respectively, over 107% relative bandwidth in the range of 6.2–20.1 GHz.