| In space exploration applications,millimeter-wave radiometers are widely used due to their advantages such as high sensitivity,good confidentiality,and flexibility,etc.This paper has successfully developed a 3mm radiation based on millimeter wave technology using waveguide-microstrip hybrid integration.Front-end system.In this paper,after researching and demonstrating the advantages and disadvantages of various types of radiometers,In this paper,after researching and demonstrating the advantages and disadvantages of various types of radiometers,the direct detection type radiometer type was finally determined.For the direct detection type radiometer type,the filter type was adopted.In this paper,cavity filter type and planar filter type are designed.The architecture form analyzes and analyzes the difficulty of design,circuit implementability,and convenience of assembly for each of the two architectural forms,and finally determines that the radiometer link design used in this project adopts cavity filters.Architecture implementation.the direct detection type radiometer type was finally determined.For the direct detection type radiometer type,the filter type was adopted.In this paper,cavity filter type and planar filter type are designed.The architecture form analyzes and analyzes the difficulty of design,circuit implementability,and convenience of assembly for each of the two architectural forms,and finally determines that the radiometer link design used in this project adopts cavity filters.Architecture implementation.All components designed in the link have been self-developed.The project design contrasts several kinds of waveguide microstrip transition structures and finally determines that the design of this project adopts a waveguide-probe-microstrip transition structure.This transitional structure has a simple circuit structure,is easy to design,and can be processed and realized.It also facilitates assembly and development.It shows that the transitional structure meets the design requirements of this topic.The cavity filter design structure adopts the H-surface waveguide filter structure.This design structure facilitates the integration of the link system and facilitates the assembly of the link.The measured insertion loss of the filter is better than 1.2 dB,and the reflection coefficient is better than-10 dB.The design of the low-noise amplifier in the paper adopts MMIC circuit design.This design has a simple structure,stable performance,and easy integration.The low-noise amplifier gain can reach 21.2dB,the reflection coefficient is lower than-9.5dB,and the noise figure is 2.8.dB.The detector was developed using OMMIC's CGY2807AUH/C1 detector tube,which is an aerospace-grade GaAs high-performance zero-bias detection diode with a detectio All components designed in the link have been self-developed.The project design contrasts several kinds of waveguide microstrip transition structures and finally determines that the design of this project adopts a waveguide-probe-microstrip transition structure.This transitional structure has a simple circuit structure,is easy to design,and can be processed and realized.It also facilitates assembly and development.It shows that the transitional structure meets the design requirements of this topic.The cavity filter design structure adopts the H-surface waveguide filter structure.This design structure facilitates the integration of the link system and facilitates the assembly of the link.The measured insertion loss of the filter is better than 1.2 d B,and the reflection coefficient is better than-10 dB.The design of the low-noise amplifier in the paper adopts MMIC circuit design.This design has a simple structure,stable performance,and easy integration.The low-noise amplifier gain can reach 21.2dB,the reflection coefficient is lower than-9.5d B,and the noise figure is 2.8.dB.The detector was developed using OMMIC's CGY2807AUH/C1 detector tube,which is an aerospace-grade GaAs high-performance zero-bias detection diode with a detection sensitivity of up to 8500mV/mW.In addition to the need for wave detection in the design process of the detector Diode input terminal for impedance matching,but also need to design a low-pass filter on the detector output signal filtering,filtered out mixed in the output of the DC signal in the fundamental and clutter signal,thereby improving the detection sensitivity.In order to achieve the design of the output voltage requirements,the output video magnification of 100 times.All components on this link have been successfully developed.n sensitivity of up to 8500mV/mW.In addition to the need for wave detection in the design process of the detector Diode input terminal for impedance matching,but also need to design a low-pass filter on the detector output signal filtering,filtered out mixed in the output of the DC signal in the fundamental and clutter signal,thereby improving the detection sensitivity.In order to achieve the design of the output voltage requirements,the output video magnification of 100 times.All components on this link have been successfully developed.In this paper,the millimeter-wave radiometer was calibrated and tested.The calibration test used a two-point calibration method.The cold source used a liquid nitrogen load(70k).The heat source was a c In this paper,the millimeter-wave radiometer was calibrated and tested.The calibration test used a two-point calibration method.The cold source used a liquid nitrogen load(70k).The heat source was a constant temperature heating load.The heating load temperature was stable at 350 k.The radiometer was successfully calibrated and the calibration curve of the radiometer was determined according to the two-point calibration equation.The overall design of this project has achieved the expected development goals.onstant temperature heating load.The heating load temperature was stable at 350 k.The radiometer was successfully calibrated and the calibration curve of the radiometer was determined according to the two-point calibration equation.The overall design of this project has achieved the expected development goals. |
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