基于射频重构的弹载探测关键技术研究

发布时间：2018-05-08 11:48

本文选题：抗干扰 + 射频重构　；参考：《南京理工大学》2017年硕士论文

【摘要】：针对目前战场复杂电磁环境以及敌方主动干扰对无线电引信造成的严重威胁,本文对基于射频重构技术的多频段无线电引信的关键技术开展研究。采用可重构射频前端,通过感知工作环境电磁信息自适应地选择工作频段,从而极大程度地提高其抗干扰能力。主要工作概括如下:(1)通过对目前几种可重构射频前端实现方法的分析,本文采用多通道集成的方式完成基于射频重构技术的弹载探测器方案设计,并阐述了各个部分的具体功能。确定将RF单刀双掷开关、电调谐滤波器、基于FPGA的数字下变频技术作为本文的研究重点。(2)采用多通道形式实现射频重构的关键部件之一是射频开关。本文结合弹载空间小、工作频段(X、Ka频段)的要求,采用RFMEMS实现单刀双掷开关。在详细分析两种典型串联、并联RFMEMS开关的工作原理及微波特性的基础上,完成了一种串并联相结合的RFMEMS单刀双掷开关的设计。并着重分析了开关插入损耗和隔离度性能参数。经仿真,在系统工作频率范围内截止开关的隔离度均低于-25dB,导通开关的插入损耗均优于-O.1dB,回波损耗均优于-20dB,从而验证了设计的正确性。(3)为节约弹载空间资源,本文在将射频信号混频以后采用同一中频处理电路。电调谐滤波器是选择两种频段第一中频信号的关键部件。本文采用微带线加载变容二极管的方式实现电调谐滤波器,并根据第一中频频率的设置完成仿真设计工作,通过Altium designer软件完成版图绘制,实测结果显示可调谐范围基本满足要求,并且插入损耗均优于-3dB。(4)为减轻信号处理芯片压力,本文对两种频段的数字采样信号均进行数字下变频处理,以降低数据流速率。文中对基于FPGA的数字下变频的实现进行研究,并在FPGA仿真软件中完成了基于cordic算法的NCO(数控振荡器)、多级级联CIC滤波器、多级HB滤波器以及分布式结构的FIR滤波器仿真设计。经对比matlab仿真结果,验证了各模块设计的正确性。
[Abstract]:In view of the serious threat to the radio fuze caused by the complex electromagnetic environment in the battlefield and the active interference of the enemy at present, this paper studies the key technologies of the multi-frequency radio fuze based on the radio frequency reconstruction technology. The reconfigurable RF front-end is used to select the working frequency band adaptively by sensing the electromagnetic information of the working environment, which greatly improves its anti-jamming ability. The main work is summarized as follows: (1) based on the analysis of several reconfigurable RF front-end implementation methods, this paper uses multi-channel integration to complete the scheme design of projectile detector based on RF reconfiguration technology. And elaborated each part concrete function. RF single-pole double-throw switch, electrically tuned filter and digital down-conversion technology based on FPGA are chosen as the focus of this paper. One of the key components of RF reconstruction in multi-channel form is RF switch. In this paper, RFMEMS is used to realize the single-pole double-throw switch. Based on the detailed analysis of the working principle and microwave characteristics of two typical series-connected parallel RFMEMS switches a RFMEMS single-pole double-throw switch combining series-parallel connection is designed. The performance parameters of insertion loss and isolation are analyzed. The simulation results show that the isolation degree of cutoff switch is lower than -25dB, the insertion loss of on-switch is better than -0.1dB, and the return loss is better than -20dB in the operating frequency range of the system, which verifies the correctness of the design. This paper uses the same if processing circuit after mixing RF signal. The electrically tuned filter is a key component in selecting the first intermediate frequency signal in two frequency bands. In this paper, the electrically tuned filter is realized by using microstrip line loaded varactor diode. According to the setting of the first if frequency, the simulation design is completed, and the layout is drawn by Altium designer software. The measured results show that the tunable range basically meets the requirements, and the insertion loss is better than -3dB.l4) in order to reduce the pressure of the signal processing chip, the digital downconversion processing of digital sampling signals in both frequency bands is carried out in this paper in order to reduce the data flow rate. In this paper, the realization of digital down conversion based on FPGA is studied, and the simulation design of NCO (NC oscillator, multistage cascade CIC filter, multistage HB filter and distributed FIR filter) based on cordic algorithm is completed in FPGA simulation software. The correctness of each module is verified by comparing the matlab simulation results.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN97;TN713

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