FMCW Frequency Source Design And Research In Ka Security And Protection Radar

Frequency Modulation Continuous Wave(FMCW)radar has advantages of low emission power,compact structure,high ranging accuracy and high anti-active interference ability.So,it is widely used in various civil and military fields.Currently,how to produce a frequency source of high resolution,high linearity,high frequency conversion speed,low power consumption,has become a developing direction of frequency synthesis technology.The main contents of this thesis are as follows:1.This thesis summarizes the current research status of FMCW radar system in recent years.The hardware architecture of FMCW radar and the principle of distance and speed measurement have been introduced.The working method of security and protection radar has been described with the illustration of “Ka-band security and protection radar system” block diagram.According to FMCW radar system indexes,the indexes of frequency source has been calculated out,a security and protection radar system FMCW frequency source has been researched and designed.After the analysis and comparison of direct digital frequency synthesis(DDS)and phase-locked loop(PLL),the structure of “DDS and PLL mix two times” has been chosen as the core design of the frequency source of this thesis to develop an X-band frequency source.2.Every chip module is designed and tested in the frequency source circuit,mainly including three aspects:(1)a HMC821 and a HMC834 PLL circuits are designed and debugged the two PLL circuits respectively.Frequency control word is calculated.Based on the working principle of the chip,the problems encountered in debugging are solved one by one after the detailed analysis.Finally,the output signal of the PLL is filtered to meet the system requirements.(2)AD9910 is designed to generate FMCW signal.Frequency control word is calculated and peripheral circuit is designed.(3)the appropriate amplifier chips are chosen and peripheral circuits are designed.According to the filter parameters,the appropriate filters are chosen to be applied in the frequency source circuit for filtering.According to the filter indexes and design methods,a filter based on Step Impedance Resonator(SIR)multi-mode X-band is designed and tested,and the test result is analyzed.3.After the completion of the debugging of the various functional modules of thesecurity and protection radar system.The frequency source,the RF front-end,the IF automatic gain control module,the baseband signal processing module and the power supply module should be assembled.The data should be analyzed which from outdoor complex environment and simple environment.The power consumption of each module and the total power consumption of the system are analyzed and compared.At last,this thesis summarizes the design of the frequency source and put forward the directions that can also be optimized and studied.