Design of a 220 GHz Broadband Sub-Harmonic Mixer Based on Global Circuit Simulation Method

The terahertz mixer is the core component of the terahertz transceiver front-end. In this paper, a 220 GHz broadband sub-harmonic mixer is designed based on global circuit simulation method. Instead of designing the passive circuit part separately by the traditional equivalent circuit method, the global circuit simulation method takes the overall performance of the mixer as the optimization goal, and the entire structure of this mixer is split into the basic transmission unit which can be optimized. The LO frequency is chosen as 110GHz with power 3mW. The simulated results show that the single sideband (SSB) conversion loss of the 220GHz broadband subharmonic mixer is under 9dB in the RF frequency range of 192GHZ-246GHz, the minimum conversion loss is 7.1dB at 221GHz. The global circuit simulation method reduces the conversion loss and the return loss of the mixer, and greatly simplifies the difficulty of designing terahertz mixer. This method can be applied to various terahertz mixers.