A Broadband Microstrip-to-Folded Substrate Integrated Waveguide Transition and In-phase Power Divider

In this paper, a novel microstrip-to-FSIW (folded substrate integrated waveguide) is proposed, which has a lot of good performances such as low return loss and insertion loss from 6GHz to 13.8GHz. The field in FSIW has been studied before and is folded in H plane for TE10 mode. The field in the underneath substrate is similar to microstrip and the whole field in FSIW is similar to stripline so that the proposed transition can be realized by using stripline. In order to reduce the radiation loss, the stripline is shielded by two rows of conduct holes to constrain the field. What is more, an inductive metal via hole is positioned on the interface of stripline and FSIW to obtain better impedance matching in a broader bandwidth. There are some other types of transitions shown in this paper for comparison and an in-phase power divider is shown. The measured results are in good agreement with the simulated results.