Design And Implementation Of Passive Module In RF Front End Of CTS System

The ability to space exploration and ground observation are becoming the key factors affecting the economic development in the region and measuring the overall national strength of a country.Remote sensing is a common means of space and ground detection.In remote sensing technology,microwave remote sensing has unique advantages,but it has developed relatively late because of the device constraints.Therefore,the application and development of microwave remote sensing has been recognized by the field of remote sensing.The CTS system designed based on the principle of LFM pulse compression has the characteristics of multi-channel,high frequency resolution and high stability.It is a radiometer working in the microwave frequency band.The design was first put forward by the Max Planck Institute for sun system of Germany,and was put into practice by ESA and other units.The RF front end of the CTS system determines its working principle and performance index.It is divided into active and passive parts from large aspects which play the same irreplaceable role.The work of this article is started from the design and implementation of the passive module of the RF front end of the CTS system.The main work of this paper is as follows: the research background and development status of the passive module of RF front end are introduced.The structure of the microwave radiometer and the RF front end frame are introduced,and the harmonic analysis and echo influence analysis are carried out on the RF front end of the CTS system,and accordingly the design index of the passive module is put forward.The design method of cross coupled cavity filter with a pair of finite frequency transmission and single cavity cross finger filters is introduced.The advantages and disadvantages of the two filters are compared.The design scheme of the cross finger cavity filter is selected.The steps and results of the design of the interdigital filter using the capacitance matrix network synthesis method are given.The design method of the microstrip power divider by the equal reflection coefficient and the design method of the rotating magnetic ferrite ring device using the first and second ring conditions is introduced,and the design results are given by the method.The computer aided software is used to design the schematic diagram,and the electromagnetic simulationsoftware is used to quickly model,simulate and optimize the design parameters.The design cycle is shortened and the design cost is reduced.The L and C band filters are simulated and realized.The peak capacity of the filter is estimated by electromagnetic simulation.The test parameters of the filter meet the expected index by testing and tuning.A Y section microstrip ferrite circulator is simulated and verified.The L and C band microstrip power dividers are simulated and implemented,and The test results generally meet the expected targets.The existing problems are analyzed.