Research On 330GHz IQ Mixer

Usually,the terahertz wave refers to the electromagnetic wave in the frequency range of 100GHz-10 THz.As a high-tech,it is the current national development demand,and the development of terahertz technology is inseparable from the improvement of device performance as a support.Terahertz IQ mixers can be used in communications,radar and instrument measurement,and have broad prospects.Based on this,on the basis of the existing research work of terahertz technology in China,the existing technical conditions are fully excavated,and the research of terahertz IQ mixing technology is carried out in depth.Thesis first introduces the domestic research trends and development trends of terahertz IQ mixers.Starting from the development history of Schottky diode,the core types of Schottky diode of IQ mixer are summarized,and the basic principle of Schottky diode barrier junction is expounded.The common topological schemes of terahertz IQ mixer are discussed.Combined with the technical characteristics of terahertz frequency band,the topological scheme of terahertz IQ mixing adopted in thesis is determined.The relationship between the mirror suppression of terahertz orthogonal mixer and the amplitude and phase flatness and isolation of local oscillator signal is derived by formula.Secondly,two terahertz quadrature mixers with local oscillator 90 ° and local oscillator in-phase input are designed and simulated,and the basic design process of terahertz hybrid integrated quadrature mixer is described.According to the characteristics of signal transmission mode,test assembly requirements and cost,the specific circuit structure of330 GHz IQ mixer circuit is selected.Then,the 330-GHz IQ mixer is simulated and optimized.According to the design frequency band and specific requirements,the diode three-dimensional packaging model is modeled.The passive structure simulation of RF coupler,local oscillator coupler and local oscillator power divider and the overall optimization joint simulation iteration process are completed.The simulation of two IQ mixers is completed,and the influence of the amplitude phase imbalance on the image rejection of the quadrature mixer is verified.The 90 degree phase shift IQ mixer based on local oscillator is processed and tested.The test results show that when the local oscillator signal is fixed at 162.5GHz frequency point and the driving power is 8d Bm,the RF signal is in the range of 300-360 GHz and the intermediate frequency is 0-30 GHz.The conversion loss of the IQ mixer is less than15.5d B.When the mixer RF signal works in the frequency band of 300-360 GHz,the S11 of the RF port is less than-17 d B,and the S11 of the IF port is less than-10 d B.Driven by the optimal local oscillator operating point,the minimum value down-conversion image rejection of the IQ mixer is 11 dBc.