Improved MMIC-to-Waveguide Integration Solution for Millimeter-wave/Terahertz Applications

In this paper, an improved integration solution is proposed to integrate millimeter-wave (MMW)/terahertz (THz) monolithic microwave integrated circuit (MMIC) with rectangular waveguide (RWG). A new via-less end-wall MS-RWG interconnection with multiple open stubs is explored to eliminate the use of via holes in higher frequency band, and thus breaks through the limitation of low-loss and wideband applications. And moreover, the bandwidth is further expanded by the open stubs with different lengths. A 340 GHz interconnection is designed and fabricated as an example for the MMIC-to-RWG application. The measured insertion loss and return loss are respectively better than 0.9 dB and 12 dB from 314GHz to 369 GHz after the microstrip transmission lines in the test fixture are calibrated. The proposed integration solution brings benefits of wideband performance, easy manufacture and low cost, which has potential applications in MMW/THz microsystems.