【作者】 李鑫；

【导师】 蒲友雷；

【作者基本信息】 电子科技大学 ， 电子信息（专业学位）， 2025， 硕士

【摘要】 线性调频雷达具有距离分辨率高、低截获特性和抗干扰能力强等优点,在精确制导、目标跟踪和气象监测等领域具有广泛应用。频率源作为一种能够产生稳定、精确频率信号的电路模块,可以为雷达、通信等电子系统提供可靠的参考频率,确保信号在时间、相位及频率上的同步性和准确性,其性能的优劣直接影响到整个系统的好坏。随着当今社会信息化程度的提升以及通信技术的不断进步,现代电子系统面临着越来越高的要求和挑战,从而促使系统对于频率源的输出频率范围、变频速度、频率分辨率、相位噪声及杂散水平等性能指标的要求也日益提高。本文以雷达系统中Ka波段线性调频源为主要研究对象,通过对频率源的合成方式和技术指标进行研究分析后,采用混合频率合成技术设计了一款宽带、低杂散线性调频源。本文首先介绍了频率合成技术的基本理论以及四种主要的频率合成技术,然后详细分析了每种频率合成技术各自的优缺点及噪声特性,并重点介绍了直接数字式频率合成(Direct Digital Frequency Synthesis,DDS)和锁相环(Phase Lock Loop,PLL)的工作原理。随后结合本课题的指标要求,选择了DDS激励PLL的技术方案产生X波段线性调频信号,再通过四倍频得到Ka波段目标信号。通过对Ka波段频率源设计方案的杂散和相位噪声特性进行分析和预估,验证了设计方案的可行性。然后根据设计指标的要求,合理选择频率源系统中的相关器件,并完成各单元电路的仿真设计。最后将各单元电路级联在一起搭建完整的频率源系统并完成了测试。测试结果表明,本课题所制作的线性调频源实现了Ka波段32-38 GHz的线性调频信号输出,在频带内信号的杂散为-44 dBc左右,相位噪声为-88 dBc/Hz@100 kHz左右,满足课题要求。更多还原

【Abstract】 Linear Frequency Modulated(LFM)radars have advantages like high range resolution,low intercept probability,and strong anti-jamming capability,making them widely applicable in precision guidance,target tracking,meteorological monitoring,and so on.As a circuit module capable of generating stable and precise frequency signals,the frequency source provides reliable reference frequencies for electronic systems such as radars and communication devices,ensuring the synchronization and accuracy of signals in time,phase,and frequency.The performance of the frequency source directly affects the overall system quality.With the increasing informatization of society and continuous advancements in communication technology,modern electronic systems are facing higher requirements and challenges,driving growing demands for frequency source performance indicators such as output frequency range,frequency switching speed,frequency resolution,phase noise,and spurious level.This thesis focuses on the Ka-band LFM source in radar systems.Through research and analysis of frequency synthesis methods and technical indicators,a wideband and low-spurious LFM source is designed by adopting hybrid frequency synthesis technology.This thesis first introduces the basic theory of frequency synthesis technology and four main frequency synthesis technologies,followed by a detailed analysis of their respective advantages,disadvantages,and noise characteristics.The working principles of Direct Digital Frequency Synthesis(DDS)and Phase Lock Loop(PLL)are emphasized.According to the project’s index requirements,a technical scheme of DDS-driven PLL is selected to generate X-band LFM signals,which are then converted to the target Ka-band signals through frequency quadrupling.By analyzing and estimating the spurious and phase noise characteristics of the Ka-band frequency source design scheme,the feasibility of the design is verified.Relevant devices in the frequency source system are reasonably selected based on the design index requirements,and simulation designs for each unit circuit are completed.Finally,the unit circuits are cascaded to build a complete frequency source system and tested.The test results indicate that the developed LFM source achieves Ka-band LFM signals output in the range of 32–38 GHz band,with spurious levels of approximately-44 dBc and phase noise of approximately-88 dBc/Hz@100 kHz within the frequency band,meeting the project requirements.更多还原