Design, Fabrication, and Measurement of the Low-Loss SOI-Based Dielectric Microstrip Line and its Components

A low-loss dielectric microstrip line (DML) integrated circuit based on silicon (Si) technology is proposed for THz applications in this paper. Using the DML, a coupler and a crossover are designed. In the proposed technology, all THz passive components are made of high-resistivity silicon on insulator (SOI) wafer. To fabricate the proposed transmission line and its components, we developed a high-precision fabrication process for the SOI wafer. A non-contact measurement technology is used to test the fabricated samples. The measured loss per wavelength of DML ranges from 0.0082 to 0.042 dB/λ over 750–925 GHz. The measured isolation of the crossover is 25.45 ± 5.54 dB, and the measured coupler factor of the coupler is –13.22 ± 3.23 dB.