A 340-GHz frequency multiplier chain based on GaN monolithic integrated circuit technology

Abstract

This article presents a high-power 340-GHz frequency multiplier chain using a × 2 × 2 multiplication architecture with two doublers based on GaN monolithic integrated circuit technology. To enhance the power-handling capability, multiple-anodes GaN Schottky barrier diodes with enhanced thermal stability and interfacial stability are employed in the designs. The GaN-based monolithic integrated circuit topology with a high-thermal-conductivity SiC substrate is adopted to address the thermal management under high-power conditions. The bias circuits with controllable transmission zeros are introduced to realize the operation adjustment and dynamic monitoring, while maintaining the conversion efficiency. Circuit analysis, parametric study and multiphysics simulation have been performed to illustrate the mechanism. The prototypes of the proposed 170-GHz and 340-GHz doublers have been implemented and tested, exhibiting a measured peak continuous-wave (CW) output power of 411 mW at 174 GHz and 82.2 mW at 338 GHz, respectively. The measured CW output power exceeds 50 mW across 320–350 GHz range, which is the highest reported performance for the 340-GHz frequency multipliers without power-combining techniques.