Research On Key Front-end Devices Of 320GHz Full Duplex High Speed Communication System

In electromagnetic waves,waves with frequencies ranging from 0.1 THz to 10 THz are called terahertz(THz)waves,which have frequencies higher than microwave and lower than infrared light in the spectrum.Therefore,it combines the features and advantages of both.The application of Terahertz band in wireless communication can not only make use of the abundant spectrum resources of this band,but also has the advantages of ultra-high bandwidth,high security and low environmental noise.It is one of the feasible solutions for 6G mobile communication technology.Full duplex wireless communication system can increase sampling rate and communication rate by multiple times,so the design of its front-end key devices is an important part of the overall system development.For the implementation of full-duplex wireless communication system in terahertz band,this thesis studies 320 GHz full-duplex communication system and its front-end key components,and provides the key technical solutions and experimental data for the front-end of this band duplex communication.In this thesis,a 320 GHz subharmonic mixer with Schottky diode is designed based on the overall structure of the communication front end.The detailed design process and simulation method are introduced,and the new compact microstrip resonator unit is used to further minimize the mixer.The design results show that with 4d Bm as the local driving power,the frequency loss of the mixer is less than 8d B at 153 GHz and 163 GHz,and within 20 GHz of the intermediate frequency output.It can meet the working conditions of the mixer in the system.Duplexer,as one of the key devices in the front-end of this communication,plays the role of separating channel units and transmitting signals in real-time in the system.In this thesis,320 GHz sixth-order reactance-coupled half-wavelength filter is designed and tested.Using this structure as channel separation unit,manifold-coupled diplexer and symmetrical three-port structure diplexer are designed respectively,and their performance is very good.The symmetrical three-port junction duplexer has a more concise optimization scheme.The processing physical test results show that the isolation is greater than 35 d B and the overall return loss is less than-15 d B in the frequency bands of 300.1GHz-309.8 GHz and 322.9GHz-332.1 GHz.At the same time,the target is for the development of multi-channel communication system.A 320 GHz quadruplexer based on symmetric five-port junction is designed.The return loss of the common port of the multiplexer is less than-15 d B in both bands,and the isolation between ports is greater than 25 d B.In order to further verify the feasibility of the full duplex communication system,the communication experiment is set up in this thesis,combined with the design of the frontend key devices above.Communication transmission at 1m distance and 10 Gbps rate can be achieved in each channel.The signal-to-noise ratio,error rate and frequency band spacing of the duplexer all meet the requirements of full duplex communication.