Self-Aligning and Flexible Dielectric Waveguide Plug for MMICs at G-Band

The packaging technology for transitions to dielectric waveguides in the frequency range above 100 GHz is complex and must be highly precise, and the waveguides are usually permanently connected. This letter presents a transition from a monolithic microwave integrated circuit (MMIC) to a flexible dielectric waveguide at G-Band (140-220 GHz), which is self-aligning and, thus, reduces the requirements for packaging accuracy. Furthermore, the transition is mechanically decoupled to avoid mechanical stress to the MMIC and to reconnect it arbitrarily often. A patch radiator on a quartz-glass carrier is excited by a coupler on the MMIC. It feeds the HE₁₁ mode into a rigid, high-permittivity dielectric dome, which increases the coupling efficiency. The flexible dielectric waveguide is placed above the dome and fixed with Rohacell half shells. The minimum insertion loss measured with a back-end-of-line (BEOL) MMIC is 3.0 dB at 168 GHz.