Aperture Synthesis Microwave Radiometer System At Ka Band And Experiments

Research on aperture synthesis radiometer technology requires comprehensive experimental platform.In this paper,An experiment system of aperture synthesis radiometer at Ka-band is designed.Testing of the experiment system and initial experiments are carried out.The requirements of aperture synthesis radiometer experiment system at Ka-band is analyzed in this paper,including functional requirements and performance requirements.The overall scheme of the experiment system is designed according to the demands.The whole experiment system includes an antenna array,a receiving channel array,a calibration source module,a three-dimensional rotatory platform,a high-precision signal acquisition system,a Gigabit networking equipment and a data processing server.The six receiving modules in the experiment system are the core components of the system.Each receiving module includes four receiving channels.The paper focuses on the design and simulation of the receiving channels.The receiving channels adopt two-stage frequency conversion structure,which consists of a low noise amplifier,an RF filter,a first mixer,a first intermediate frequency amplifier,a first intermediate frequency filter,a second mixer,a second intermediate frequency amplifier,a second intermediate frequency filter and an adjustable attenuator and other components.The two local oscillator sources provide the local oscillator signal for the two-stage mixer via the power divider.Each part of the experiment system was tested.According to the test results,the data acquisition,the control program and the receiving modules were improved.In the experiment system,the measurement of the interference fringes,point source imaging and natural scene imaging were carried out,which indicated that the designed experiment system could be used as an experimental platform for the study of aperture synthesis technology.