W波段高性能检波电路研制

发布时间：2018-07-08 13:12

本文选题：W波段 + 检波器　；参考：《东南大学》2015年硕士论文

【摘要】：随着科技的高速发展,毫米波辐射计广泛应用于遥感、探测、安检等重要领域,具有广阔的市场和巨大的商业价值。检波电路作为辐射计的核心部分,尤其是直接检波式电路,因其结构简单,系统噪声温度低,是近些年来辐射计接收前端研究的热点课题。因此,本文将对W波段检波电路进行研究。在W波段,测试仪器接口均为波导口,本文首先研制了波导微带鳍线过渡结构,利用Spline曲线取点优化,缩短了鳍线过渡段的尺寸；通过在介质基片末端加凸型槽,改善了接口处阻抗的不连续性,最终进行了背腔结构的实物加工验证。实验结果表明,S参数实测曲线和仿真曲线一致性高,背腔过渡结构在84～110GHz内,反射系数小于-12dB,插损小于2dB,在整个80～110GHz频带内,反射系数小于-9dB。单侧过渡插损小于0.9dB。随后,利用该过渡转换结构,我们分别对W波段检波器和低噪声放大器进行了研制。W波段检波器采用了国内目前较少研究的VDI公司零偏置肖特基二极管,并编程提取了该二极管的Spice模型参数,最终利用该参数设计了检波器,实验结果表明在工作频带84～94GHz内,电压灵敏度大于800mV/mW,在92GHz处电压灵敏度高达1900mV/mW,接近国外先进水平。W波段低噪声放大器,我们采用了Gotmic公司LNA单片,通过两级MMIC芯片级联,实现预期36dB左右增益。为了防止芯片级间反馈,在两级芯片间加入了隔墙,并对隔墙进行了仿真；设计了时序电源模块,完成单电源供电；设计了低噪放的腔体结构,分别将低噪放高频部分和低频部分放在腔体的正反面,实现了物理隔离。最终完成装配和测试,实验测得在工作频带84GHz-94GHz内,低噪放增益为18±2dB,在中心频点89GHz处,1dB压缩输出功率为0dBm。增益没有达到预期指标,通过反复实验,推测原因主要在于芯片自身增益不足。最终,利用两级低噪放级联实现36dB左右的增益,计算得到系统的温度灵敏度为0.6K,达到预期目标。
[Abstract]:With the rapid development of science and technology, millimeter-wave radiometers are widely used in remote sensing, detection, security inspection and other important fields, with a broad market and huge commercial value. As the core part of radiometer, especially the direct detector circuit, the detection circuit is a hot topic in recent years because of its simple structure and low system noise temperature. Therefore, the W-band detection circuit will be studied in this paper. In the W band, the interface of the instrument is waveguide port. Firstly, the waveguide microstrip finline transition structure is developed in this paper. The size of the finline transition section is shortened by using the Spline curve to optimize the fin-line transition section, and the convex groove is added to the end of the dielectric substrate. The discontinuity of the impedance at the interface is improved, and the physical processing of the back cavity structure is finally verified. The experimental results show that the measured curve and the simulation curve are in good agreement with each other. The reflection coefficient of the back cavity transition structure is less than -12 dB and the insertion loss is less than 2 dB. The reflection coefficient is less than -9 dB in the whole frequency band of 80,110GHz. The unilateral transition insertion loss is less than 0.9 dB. Then, using the transition structure, we developed the W-band geophone and the low-noise amplifier respectively using the zero-offset Schottky diode of VDI Company, which is seldom studied in our country. The Spice model parameters of the diode are extracted by programming. Finally, the geophone is designed by using this parameter. The experimental results show that the detector is in the operating frequency band of 844GHz. The voltage sensitivity is greater than 800 MV / mW, and the voltage sensitivity is as high as 1900 MV / mW at 92 GHz, which is close to the foreign advanced level. W band low noise amplifier. We adopt Gotmic LNA monolithic and cascade through two MMIC chips to achieve the expected gain of about 36dB. In order to prevent the feedback between the chips, the partition wall is added between the two chips, and the partition wall is simulated; the sequential power supply module is designed to complete the power supply of the single power supply; the cavity structure of low noise amplifier is designed. The high frequency part and the low frequency part of the low noise amplifier are placed on the opposite side of the cavity, respectively, and the physical isolation is realized. The final assembly and test are completed. The experimental results show that the low noise amplifier gain is 18 卤2 dB in the operating band of 84 GHz to 94 GHz, and the output power of 1 dB is 0 dB at 89GHz at the central frequency point. The gain is not up to the expected target. Through repeated experiments, it is speculated that the main reason is that the gain of the chip itself is insufficient. Finally, the gain of 36dB is realized by using two-stage low noise amplifier cascade, and the temperature sensitivity of the system is 0.6K, which achieves the expected goal.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN763.1

【相似文献】