【作者】 陈卉；

【导师】 郑正奇；

【作者基本信息】 华东师范大学 ， 通信与信息系统， 2009， 硕士

【摘要】 微波多普勒雷达系统在民用上与军事上都得到了广泛的应用与研究。民用上,系统可应用于交通测速报警系统以及需要自动感应控制的场所;也可应用于天气预报,探测近场的雷雨、暴雨、大范围降水等气象目标信息。军事上,可以探测导弹,飞机与舰船等。其社会效益和经济效益都是很显著。因此,开展微波多普勒雷达系统的研究,有着重要的意义。根据实际应用需要,设计出一个能够检测短距离里低速运动物体的系统。本论文研制出一种低成本、结构简单、小型化的微波多普勒雷达系统,并在实验室环境下测试该系统,得到了较好的测试结果。本论文设计的微波多普勒雷达系统包含两个组成部分:微波多普勒雷达前端系统与收发天线。收发天线部分采用的是单天线,通过四元微带天线阵来实现。根据理论公式计算出天线尺寸,使用HFSS软件仿真,观察仿真结果。天线的指标需要设计出宽带宽,窄方向角的天线,同时需要实现天线的小型化与低成本。为达到窄方向角目标,并考虑到天线的小型化要求,论文采用2*2四元微带天线阵,同时通过调整两元之间的距离来实现窄方向角要求。由于微带天线的带宽比较窄,不能满足指标要求,通过一些改进,得到较宽的频带。根据理论尺寸,制成PCB板,用网络分析仪扫频测试天线的中心频率S11与带宽。基本满足要求,通过进一步调试修正,改变四个阵元的大小,经测试实现了带宽大于500MHz宽频带(S11＜-10dB)。在暗室里测试天线的方向角,得到较窄的方向角。微波多普勒雷达前端系统采用微带电路设计,系统包括并联反馈型DRO振荡器、环形电桥混频器、二等分功分器。DRO振荡器是通过公式计算设计出电路,然后通过频谱分析仪测试调试,实现DRO振荡器稳定的频率输出10.8GHz,输出频率不受电源电压的改变而改变,机械调谐频率达到100MHz以上。环形电桥混频器和二等分功分器,先将理论值设计成电路在ADS软件中仿真优化,然后PCB制版之后通过频谱分析仪和网络分析仪测试电路性能。最后测试整个多普勒雷达前端系统的性能,用频谱分析仪测试混频器输出的中频信号。将多普勒雷达前端系统与天线集成进行整机测试,测试结果表明了该雷达可用于低速运动目标检测。更多还原

【Abstract】 Microwave Doppler radar system is being studied and used widely in civil and military field. In civil, this system can be used to traffic speed alarm system and the place where needs auto-sensing control. The system also can be used to weather forecast and detect information of weather objects such as thunderstorms, heavy rain, large-scale. It is also used to detect weapon, plane and naval vessel, and so on. One promising technology, which has been demonstrated to be effective, is microwave Doppler radar system. So the design and research for the system is very import.According to needs of application, it needs to design a system which can detect lows peed moving target. The thesis studies a low cost, simple and compact microwave Doppler radar system which can get good result in the environment of lab. Microwave Doppler radar system has microwave Doppler radar front-end system and send-receive antenna.The send-receive antenna is single antenna which is a 2*2 microstrip antenna array. According to the theoretical formula calculating the size of the antenna, then using HFSS to simulate and observe results. According to the needs of compact and narrow angle antenna, the thesis designs a 2*2 microstrip antenna and achieves the needs of narrow angle antenna through adjusting the distance between two patches. The thesis improves antenna array and gets wide bandwidth to meet qualifications. According to theoretical size, making PCB board, test antenna’s center frequency S11 and bandwidth with network analyzer sweep. The thesis debugs and amends the antenna by changing the size of four patch of antenna array. The test results show that the bandwidth is about 500MHz (S11<-10dB) and narrow angle can be achieved in dark room.The thesis uses microstrip circuit to design microwave Doppler radar front-end system. The system contains parallel DRO oscillator, mixer bridge ring, the second sub-power splitter. The thesis designs DRO oscillator according to theory size and test by Spectrum Analyzer. DRO oscillator has the stability frequency output 10.8GHz which not changes by the power supply voltage, and mechanical turning frequency above 100MHz. The thesis designs ring bridge and second sub-mixer splitter according to the theoretical value, then tests the performance of PCB circuit with spectrum analyzer and network analyzer.Finally, the thesis tests the performance of Doppler radar front-end system, and IF mixer output signal with spectrum analyzer. Then integrating Doppler radar front-end system and antenna, testing the whole system, results show that the radar can be used for low-speed moving target detection.更多还原