Research On 220GHz Tripler

Terahertz technology is a frontier discipline with rapid development in recent years,which has been paid more and more attention from all over the world.With the development of science and technology,the terahertz system is coming into the spotlight in the fields of communication,radar,security inspection and biomedicine.As the "heart" of the system,the terahertz source plays an important role.As a key component of the source,the frequency multiplier has received more and more attention.In this paper,we present the frequency multiplier with the structure of cavity innovatively and the circuit form of traditional frequency multiplier is changed in order to obtain better performance.Firstly,The paper introduces the theory of cavity frequency multiplying and analyzes its advantages and disadvantages.Then it expounds the design of 220GHz frequency tripler and 140GHz frequency doubler to verify the feasibility of this circuit according to its design idea and simulation process.In the design,the first thing is to select diodes and establish the 3D electromagnetic model and equivalent circuit model for extracting,the tube core parameters.Then design the input waveguide,waveguide filter,diode matching circuit respectively.Finally,do the simulation of whole structure and circuit using HFSS and ADS to check the perform of output power and efficiency.In 220GHz band,three frequency tripler are designed by changing the way of waveguide impedance matching,and the odd frequency multiplier circuit of the cavity structure is verified.The simulation shows the maximum output efficiency is 6%,7.9%and 11.7%,under the 23dBm basic power drive,the maximum bandwidth of efficiency greater than 5%is 10.5GHz,and the maximum output power are 13.61mW,15.83mW and 23.4mW.The simulation shows that the frequency multiplying efficiency will be further improved when the driving power is raised.In the experimental part.The maximum output power of 220GHz frequency triplers are 0.81mW,1.87mW and 1.48mW respectively under 17dBm-20dBm power driving.The best efficiency is 0.68%,2.54%and 1.47%respectively,and the maximum bandwidth of 1mW power output is 7.5GHz.The cavity frequency multiply theory and its structure presented in this paper are innovative.Based on the measured results of 220GHz frequency triplers,the validity of the structure is verified.This paper provides a new idea for the design of a new frequency doubling circuit,and provides a reference for the follow-up study of the frequency doubling structure without substrate.