220GHz Multi Circuits Integration Technology

With the rapid development of semiconductor technology and high-precision micromachining technology,as well as the national investment in the electronic industry,terahertz solid-state circuit technology has gradually moved from laboratory to practical application.The single function circuit has not been able to meet the requirements of the practical application system for volume,weight and power consumption.The restrictions are even more severe especially in aerospace and other application fields.In the future,multifunctional integrated circuits will be the inevitable trend of terahertz solid-state circuit.The research on this circuit is of great significance and will achieve miniaturization,chip based and practicality of terahertz solid-state system.To realize a miniaturized high-speed communication system,this dissertation focuses on the technology of terahertz solid-state multi-circuit integration technology.Two kinds of active circuits(sub-harmonic mixer and tripler)and two kinds of passive circuits(branch-waveguide hybrid coupler and pseudo elliptic waveguide bandpass filter)are studied,which constitute the RF front-end of the receiver.Based on the theory and performance of each circuit,a novel terahertz solid-state integrated circuit and the frontend of terahertz receiver are proposed.In addition,the experiments of a 20 GHz wideband real-time signal blind detection and a 12.8Gbps high-speed communication data transmission are successfully carried out.This dissertation mainly includes the following three aspects:(1)Key circuits in terahertz receiver.The key circuits mainly refer to the sub harmonic mixer circuit and its LO drive circuit(frequency multipliers).The function of sub harmonic mixer in the RF front-end is frequency shifting.The characteristics of the nonlinear circuit directly affect the noise performance of the system.In the dissertation,based on the study of the physical mechanism of Schottky barrier diode and the characteristics of carrier transport in Schottky junction,the influence of diode parameters and package parasitic parameters on the performance of frequency conversion loss is analyzed.The precise electromagnetic model of the mixer diode has been deeply studied and a 220 GHz low loss sub harmonic mixer is designed.In addition,frequency multiplier technology is an important way to generate terahertz signal and tripler is an efficient way to achieve LO driving source.Similarly,as a non-linear circuit,varactor diode is the core device of multipliers.Through theoretical research,the influence on the performance of the tripler caused by varactor diode is analyzed,the electromagnetic model of the tripler is established,and a 110 GHz high-efficiency tripler to drive the 220 GHz subharmonic mixer is also designed.(2)Terahertz multi-circuit integration technology.The passive circuits also do great contribute to the high-performance receiver front-end.The dissertation focuses on the terahertz branch waveguide hybrid coupler and pseudo elliptical waveguide band-pass filter.The biggest problem of multi-circuit integration is that each circuit cannot be detected effectively,and the coupler solves this problem.In this dissertation,the theory of traditional branch waveguide couplers is deeply analyzed.Based on the traditional odd and even mode analysis method,the mode matching method is introduced innovatively,and an accurate and efficient coupler modeling method is proposed.Compared with the traditional method,this method has considered the influence of waveguide discontinuity and avoids the inevitable error caused by the traditional method in terahertz band.Based on this theoretical innovation,this dissertation proposes a novel coupler circuit structure.Compared with the traditional 5-branch structure,the size decreases by 47% with the same operation bandwidth.At the same time,in order to avoid the interference caused by double side band transmission and realize single side band communication transmission,this dissertation proposes a pseudo elliptical waveguide band-pass filter in terahertz band,which has a 30 d B rectangular factor of 0.71 and good frequency selectivity.Finally,this part proposes a layout of multi-functional integrated circuit.As the front end of the receiver system,it can directly realize the single sideband transmission,and can ensure a good working state of the mixer's LO source at the same time.Compared with the traditional multi module connection circuit,the volume of the single module multifunction integrated circuit decreases 90% and weighs only 90 g,which lays a good foundation for the realization of miniaturized receiver in high-speed communication system.(3)The research on terahertz high-speed communication miniaturized receiver.Based on the breakthrough of related circuits and theories,this dissertation also studies the terahertz high-sensitivity signal detection and high-speed communication technology,and constructs the 220 GHz wideband signal blind detection experimental verification system and high-speed communication experimental verification system.The real-time signal detection bandwidth of the 220 GHz signal blind detection system is 20 GHz,and the signal frequency resolution is up to 1k Hz.The 220 GHz high-speed communication system adopts the dual channel transmission structure.Under the condition of the poor performance of the analog to digital converter,it realizes the high-speed data transmission with the data rate of 12.8Gbps,and verifies the relevant HD video services.Through the research of this dissertation,a multi-circuit integration terahertz receiver front-end is developed,which greatly reduces the volume and weight of the receiver.In addition,the feasibility of terahertz broadband receiver and high-speed communication is verified,which lays an important theoretical and technical foundation for the application of short-distance and large-capacity communication on the ground and space communication.