Research On The Front End Of Terahertz Multi-Transmitted And Multi-Received Communication System

Terahertz wireless communication technology is one of the important ways to realize future high-speed mobile communication technology.It uses terahertz waves as signal carriers and can carry large-capacity information transmission in free space channels.In order to meet the application requirements of the terahertz tracking system,this paper focuses on the front end of multi-transmitted and multi-received terahertz communication system.Based on a new terahertz communication system architecture,the critical circuits required for the RF front-end have been optimized,processed and tested,and the frontend experiments of the communication system have been performed.The development of terahertz key circuits affects the performance of the entire terahertz wireless communication system.Unlike traditional point-to-point communication systems,circuit consistency is also a research focus in circuit performance,and it also affects the overall performance of the system in this paper.Through the simulation method combining "field" and "circuit",the paper optimizes the 220 GHz sub-harmonic mixer and 110 GHz third frequency multiplier.After detailed tolerance analysis of the circuit substrate and diode assembly,the developed subharmonic mixer and third frequency multiplier have good tolerance performance,which improves the consistency of circuit performance and establishes a multi-transmitted and multireceived communication system.The test results show that the frequency conversion loss of the mixer is better than 12.5dB in the frequency range of 213GHz~219GHz;the power output of the frequency multiplier is better than 3mW in the frequency range of 105~ 115 GHz,which can drive the mixer to work well.At the same time,in order to realize single-sideband communication,based on the direct-coupled cavity structure,a bandpass cavity filter with high rectangular coefficient is developed.The filter has an insertion loss of less than 1.5dB and a return loss of more than 15 dB in the range of 212~220GHz in the passband,and a rejection of more than 20 dB in the range of 200~210GHz in the stopband.In the terahertz band,there is a lack of related equipment for phase testing,so the phase testing of each channel is also very important.This article adopts a new phase test method.First,debug the signal strength of a single channel,and then use the power synthesis method to achieve phase calibration between multiple channels.The final test shows that the amplitude difference between the four channels of the transmitter is less than 3dB and the phase difference is less than 12.5 °,which meets the requirements of the communication system for the front end.The research on the front end of multi-transmitted and multi-received terahertz communication system provides relevant technical support for the development of a multi-channel terahertz communication system in the next stage.It also has certain academic significance and engineering application value for the promotion of future highspeed mobile communication technology.