X波段FMCW导航雷达射频前端设计与实现

针对基于锁相环技术的雷达射频前端无法快速变频，以及传统雷达采用多次倍频、混频带来较大杂散的问题，提出一种将直接数字频率合成(direct digital synthesizer， DDS)技术、上变频技术和倍频技术相结合的射频收发前端设计方案。该设计方案中DDS具有输出信号灵活、变频快速等特点，使输出的雷达信号具有高稳定性和高准确度；同时该设计采用零中频接收机方案，降低设计的复杂度并减少镜像频率的干扰。对系统方案进行了对比分析，得到了较优设计方案，并根据设计方案完成芯片选型；利用ADS2012仿真软件进行了链路仿真并参考芯片数据手册完成原理图绘制和印制电路板(printed circuit board， PCB)布局布线；完成了元器件焊接和硬件测试。实测结果显示，此设计方案基本满足X波段调频连续波(frequency modulated continuous wave， FMCW)导航雷达射频前端的设计要求。

Design and implementation of FMCW navigation radar RF front-end in X-band

To solve the problems that the RF front-end of radar based on the phase-locked loop can not be rapidly frequency-converted, and the conventional radar adopts multiple frequency doubling and mixing to bring large spurs, a RF front end design that combines direct digital synthesizer technology, up-conversion technology and frequency doubling technology is proposed. This design of DDS has the characteristics of flexible output signal and fast frequency conversion, so that the output of radar signal has high stability and high accuracy. Simultaneously, the design adopts zero IF receiver scheme to reduce the complexity of the design as well as the image frequency interference. Firstly, this paper analyzes the system schemes and gets a better one, and then we select the chips according to the scheme. Secondly, this paper uses the ADS2012 simulation software to simulate the link, in the meanwhile complete the schematic drawing and the PCB layout on the basis of the chip datasheet; Finally, this paper completes component welding and hardware testing. The experimental results show that the scheme basically meets the design requirements of the X-band FMCW navigation radar RF front-end.