Research On Key Technologies Of On-chip Wideband THz Signal Detector

The terahertz spectrum,wedged between microwave and infrared,has great application potential compared with adjacent spectrum.Through the study of terahertz technology,terahertz frequency band has shown wide application value in high-speed network communication,imaging,spectral analysis,and other fields.In the past few decades,a great deal of work has been done in the fields of electronics and optics in the synthesis and detection of terahertz signals,which has confirmed the application potential of this spectrum.However,due to the unique frequency range of terahertz,the implementation of high integration,high resolution,and wide frequency range of terahertz detection system on the chip-scale platform is still a great challenge.Therefore,this thesis takes the high-resolution wideband terahertz detection system as the research topic.This thesis focuses on the wideband terahertz signal sensing technology,the spectrum detection technology of terahertz signals,and the design of the monolithic integration of the terahertz detection system.The main research contents are divided into the following three parts:The first part introduces the concept and working principle of terahertz sensing surface.Then the analysis methods of sensing surface are introduced.The main types and principles of terahertz detection circuits are introduced after that.Finally,the terahertz spectrum algorithm is introduced.The spectrum of the terahertz signal can be calculated based on the detection results of the terahertz detection system according to the algorithm.In the second part,a wideband terahertz sensing surface based on a rotationally symmetric multi-branch structure is proposed.Combined with electromagnetic field theory and transmission line theory,the design method of the sensing surface is analyzed.Then the performance of sensing surface is further analyzed through electromagnetic induction analysis.The sensing surface utilizes the resonant frequency distribution characteristics of the multi-branch structures with different lengths.Thus,wideband sensing effect can be realized in a small area.At the same time,the structure also adopts a rotationally symmetrical design,which has a strong induction capability for incident terahertz signals of different polarization directions.The sensing surface has the advantages of compact structure,wide sensing frequency range,and stable sensing effect for signals in different polarization directions.In the third part,a wideband high resolution terahertz signal detection system based on a rotationally symmetrical multi-branch structure sensing surface is proposed.The system includes a rotationally symmetric multi-branch sensing surface,a detector array,operational amplifiers,and output buffers.Through the measurement of the electrical signal on the sensing surface,the spectrum of the incident terahertz signal can be calculated using the spectrum algorithm.The measurement results exhibit that THz spectroscope features a 140 to 500 GHz detection range with 1 MHz frequency resolution.