Versatile Transition for Multilayer Compact Devices in Empty Substrate Integrated Waveguide

Empty substrate integrated waveguide (ESIW) devices can provide high quality and completely integrated devices, but they are usually larger than the same ones implemented with alternative technologies. One of the most extended strategies to compact electronic devices is the use of multilayer technology. Nevertheless, to perform multilayer devices in ESIW, a versatile and efficient transition between the guides in different layers is needed. Currently, only one multilayer device is known in this ESIW technology, which is a transition between a pair of guides built in contiguous layers that requires complex and nonstandard 3-D manufacturing processes. In this letter, a multilayer transition to connect a pair of guides separated by an arbitrary number of layers is successfully designed and experimentally validated without 3-D manufacturing processes. This novel and versatile transition opens the way to further develop multilayer compact devices in the ESIW technology such as compact filters.