Ridge Gap Waveguide Layer Transition for Compact 3-D Waveguide Packaging Application

In this letter, a ridge gap waveguide (RGW) layer transition is proposed for compact 3-D packaging application. The RGW layer transition can increase the layout space in the vertical direction of the RGW packaging. The proposed RGW layer transition consists of a normal RGW, a double RGW (DRGW), and an inverted RGW (IRGW). The electromagnetic field coupling between different RGW layers is achieved using a double-ridge probe. Finally, a back-to-back RGW layer transition prototype is designed and fabricated. The measured results show an operating frequency ranging from 37.7 to 43.5 GHz, with a fractional bandwidth of 14.3%. Within the working frequencies, the return losses are better than 12 dB and the insertion losses are around 1.2 dB. There is a good agreement between the measurements and the simulations.