Millimeter-Wave Vertical Transitions Between Ridge Gap Waveguides and Microstrip Lines for Integration of MMIC with Slot Array

This paper presents two low-loss vertical transitions between ridge gap waveguides and microstrip lines. The transitions can be utilized as packaging techniques for system level integration of MMICs with waveguide components such as slot array antennas. Both vertical transitions feature microstrip lines being the bottom layer but facing opposite directions. The first vertical transition consists of a microstrip line facing upwards with a patch in the end. Simulation results show that the reflection coefficient is better than -15 dB from 74 to 82 GHz. The second transition of microstrip line facing downwards features E-plane probe with back-short cavity surrounded by periodic pins. Simulation results show that the reflection coefficient is better than -15 dB from 71 to 86 GHz. Comparing with other same layer transitions, the vertical solutions provide more flexibility for the routing of antenna feeding line and have the ability of implementing a more compact design.