A 0.2 THz Sub-Harmonic Mixer with Vertical Waveguides for 3-D Integrated Systems

A 0.2-THz Schottky diode-based sub-harmonic mixer with vertical waveguides is presented in this paper. This mixer is designed for use in 0.2-THz 3-D integrated systems. To achieve vertical interconnection with other components, two vertical waveguide-to-microstrip transitions are designed in the mixer. A LO-IF diplexer is designed to improve the isolation between the RF port and the IF port. In addition, a 3-D electromagnetic model of the Schottky diode is established to characterize the parasitic parameters, and a Spice model is used to characterize the current-voltage nonlinearity. Based on the proposed structure, a separate mixer module is designed, fabricated, and measured to demonstrate the performance. The SSB conversion loss of the mixer is better than 14 dB at the 198-216-GHz bands, showing a good performance.