Development of High Power 220 GHz Frequency Triplers Based on Schottky Diodes

In this paper, the development of two high power 220 GHz frequency triplers is proposed. The GaAs Schottky diodes with six nodes are applied to realize high efficiency 220 GHz tripler, while the application of GaN Schottky diodes with eight nodes is another attempt to improve power handling of the 220 GHz tripler. To reduce thermal effect of high power multipliers, the AlN substrates with high thermal conductivity are applied to provide better heat dissipation at the diode areas. A combination of electrical and thermal model of the Schottky diodes is established while the optimization of 220 GHz triplers are realized with 3D electromagnetic (EM) simulation and harmonic balanced simulation. Good agreement is achieved between the simulated results based on electro-thermal model and measured performances of the triplers. At room temperature, peak efficiency of the tripler based on GaAs Schottky diodes is 17.8%, while the maximum output of the tripler is 38.2 mW with 300 mW input power. As for the 220 GHz GaN Schottky diode tripler, measured results show that the maximum power handling is beyond 400 mW. The peak efficiency and maximum output are 4.7% and 18.4 mW, respectively. The proposed methods of developing high power multipliers can be applied in higher frequency band in the future.