Miniaturized Folded Ridged Half-Mode Substrate Integrated Waveguide

Significant miniaturization of substrate integrated waveguides (SIW) is presented, utilizing folded techniques on ridged half-mode substrate integrated waveguide transmission lines. By moving the ridge structure inside the main waveguide channel, the transverse field distribution is wrapped around two substrate layers, achieving a miniaturization of 25.2% compared to ridged half-mode SIW, and 56.7% compared to half-mode SIW. The complex propagation constant of the folded ridged half-mode substrate integrated waveguide is extracted, showing negligible loss in performance compared to the ridged half-mode structure, and improved performance compared to conventional half-mode SIW. To verify performance experimentally, a folded ridge half-mode SIW is fabricated, and the measured scattering parameters are compared to simulation, with good agreement. To the best of the authors' knowledge, this work presents the first folded ridge half-mode SIW structure in the literature.