The Research Of W-band Frequency Multiplication By Harmonic Power Synthesis Technology

Millimeter-wave is an indispensable part of the whole electromagnetic spectrum.Millimeter-wave is characterized by wide band and short wavelength,and has important application value in many fields such as communication,radar,guidance,remote sensing,radio astronomy and so on.It is difficult to develop fundamental frequency oscillator with large output power,high stability and good noise performance in millimeter-wave band,and using low-frequency signal to produce higher harmonic through frequency multiplication has become an important way to obtain millimeter-wave source.In this paper,the development dynamics and related basic theory of millimeter-wave frequency multiplier were introduced,on this basis,a 110 GHz single-way frequency tripler,two-way frequency tripler and four-way power-combined frequency tripler based on waveguide T-junction were designed respectively,which were all based on Schottky varactor.The frequency multiplier was in the form of hybrid integrated circuit composed of waveguide and microstrip line.In order to enhance power capacity,each way of the frequency multiplier circuit took the form of varactor pairs.The development of the frequency multiplier circuit adopted the method of "Field" and "Circuit" joint simulation to combine the linear part and nonlinear part of the circuit organically.Firstly,the relevant parameters required for the modeling of varactor were obtained by curve fitting,the varactor model was built,on the other hand,the models of passive structure such as filters,input and output transitions were built and simulated.Then the simulation data was used to perform harmonic balance optimization simulation with the built varactor model,the best matching structure of the frequency multiplier circuit could be obtained.Finally,the frequency multiplier circuit was processed,assembled and measured.The output power of the designed single-way frequency tripler is above 5mW from 105 GHz to 110 GHz when driven by 100 mW,the output power is 9.03 mW at 110 GHz,the maximum is 10.25 mW at 108.9GHz,which corresponds to the efficiency of 10.3%.The output power of the designed two-way frequency tripler is above 10 mW from 101 GHz to 108 GHz when driven by 200 mW,the output power is 9.15 mW at 110 GHz,the maximum is 20.23 mW at 103.8GHz,which corresponds to the efficiency of 10.1%.The power synthesis efficiency of the designed four-way frequency tripler based on waveguide T-junction is during 70%-80% at 102.3GHz,105.6GHz,106.5GHz,108.3GHz,110.1GHz and 113.4GHz,the maximum output power is 24.65 mW at 101.7GHz.The developed frequency multiplier can be used as driving source to provide solution for millimeter-wave communication system,on the other hand,the design of this topic also has important significance for the study of terahertz multiplier.