亚毫米波准光单脉冲天馈的理论技术研究

发布时间：2018-05-15 20:19

本文选题：亚毫米波 + 准光技术　；参考：《东南大学》2016年博士论文

【摘要】：亚毫米波介于微波毫米波与红外之间,兼有二者的优点,同时又能克服它们的缺点,使其在通信、目标探测、制导、空间遥感等方面具有重大的科学价值和广阔的应用前景。单脉冲技术是一种精密角度测量技术,已被广泛应用于各种卫星通信及精确制导雷达系统中。近年来,微波毫米波频段的单脉冲天线已经得到了广泛而深入的研究,但工作于亚毫米波频段单脉冲天馈的研究尚未见到相关报道。鉴于此,本文对亚毫米波单脉冲天线进行了一些相关的研究,这对于亚毫米波单脉冲天线的发展具有重大意义。论文主要工作和贡献如下:1)研究了准光和差比较器的基本原理并采用基于时域有限差分法(FDTD)的精确数值分析方法仿真、优化准光和差比较器的性能,在此基础上基于准光技术设计了一种工作于亚毫米波频段的单脉冲天馈系统,提出了采用介质棱镜校正口径面场分布的方法来改善和差辐射特性,有效地抑制了和波束的副瓣电平,并完成了实物的加工制作及实验测试,测试结果与仿真结果吻合良好。2)介质透镜和衍射光学元件在亚毫米波准光单脉冲天线方向图改善方面的研究。首先通过对基本遗传算法中选择、交叉、变异算子的改进,提出了一种具有较强全局寻优能力和收敛速度的改进型遗传算法,进而结合时域有限差分方法(FDTD)和衍射积分公式(Stratton-Chu)优化设计修正双曲型介质透镜和衍射光学元件,使得准光单脉冲天线的和差辐射特性得到了较好的改善。3)基于准光技术设计并实现了一种工作于亚毫米波频段的单脉冲天线,该单脉冲天线主要由准光和差比较器、波束波导馈电系统、卡塞格伦双反射面构成。四个椭球面反射镜构成的波束波导传输系统可以实现电磁波束的低损耗、高效传输及波束束腰变换,卡塞格伦双反射面实现了高增益、低副瓣的方向图辐射特性。最后,完成了所设计准光单脉冲天线的实物加工和实验测试,实测结果与仿真结果吻合良好,验证了设计的有效性。4)在亚毫米波频段研究并设计了能够同时实现方位面、俯仰面和差辐射特性的二维准光单脉冲天线。首先,基于矩阵论和傅里叶变换技术分析了准光型法拉第旋转器的特性,设计了应用于收发隔离通道的准光型环行器;其次设计了可双极化工作的3dB波束分束器,进而研究分析了所设计的二维准光和差比较器的性能;然后基于遗传算法优化设计了一种介质透镜,使得所设计的二维准光单脉冲天线的和差辐射特性得到了较大的改善;最后完成了整个单脉冲天线的结构设计,为后续的实验验证奠定了基础。
[Abstract]:The sub-millimeter wave lies between microwave millimeter wave and infrared wave. It has the advantages of both, and it can overcome their shortcomings, which makes it have great scientific value and broad application prospect in communication, target detection, guidance, space remote sensing and so on. Monopulse technology is a kind of precise angle measurement technology, which has been widely used in various satellite communication and precision guidance radar systems. In recent years, the monopulse antenna of microwave millimeter wave band has been widely and deeply studied, but the research of monopulse antenna in sub-millimeter wave frequency band has not been reported. In view of this, this paper has carried on some related research to the sub-millimeter wave monopulse antenna, which has the great significance for the development of the sub-millimeter wave monopulse antenna. The main work and contributions of this paper are as follows: (1) the basic principle of quasi-optical and differential comparator is studied, and the performance of quasi-optical and differential comparator is optimized by using an accurate numerical analysis method based on FDTD (finite-difference time-domain method). On the basis of this, a monopulse antenna feed system working in submillimeter wave frequency band is designed based on quasi-optical technique. A method of correcting aperture field distribution by using dielectric prism is proposed to improve the harmonic radiation characteristics. The sidelobe level of the sum beam is effectively suppressed, and the fabrication of the object and the experimental test are completed. The experimental results are in good agreement with the simulation results. 2) the study of improving the pattern of submillimeter wave quasi-monopulse antenna with dielectric lens and diffractive optical elements. By improving the selection, crossover and mutation operators in the basic genetic algorithm, an improved genetic algorithm with strong global optimization ability and convergence rate is proposed. Furthermore, the modified hyperbolic dielectric lens and diffractive optical element are optimized by using FDTD (finite difference time domain method) and the diffraction integral formula (Stratton-Chu). The sum difference radiation characteristics of quasi-optical monopulse antenna are improved better. 3) based on quasi-optical technology, a monopulse antenna working in sub-millimeter wave band is designed and implemented. The monopulse antenna is mainly composed of quasi-optical and differential comparator. The beam-guide feed system is composed of Cassegrain double reflector. The beam-guide transmission system composed of four ellipsoidal reflector can realize the low loss of electromagnetic beam, high efficiency transmission and beam waist transformation. Cassegrain double reflector realizes the radiation characteristics of high gain and low sidelobe. Finally, the design of quasi-optical monopulse antenna is processed and tested. The measured results are in good agreement with the simulation results, and the validity of the design. 4) in the sub-millimeter wave band is studied and the azimuth plane can be realized at the same time. Two-dimensional quasi-optical monopulse antenna with pitch plane and differential radiation characteristics. Firstly, based on matrix theory and Fourier transform technique, the characteristics of quasi-optical Faraday rotator are analyzed, and a quasi-optical circulator is designed for transceiver isolation channel. Secondly, a dual-polarizable 3dB beam splitter is designed. Then, the performance of the two-dimensional quasi-optical and differential comparator is studied and analyzed, and then a dielectric lens is optimized based on genetic algorithm, which improves the sum difference radiation characteristics of the two-dimensional quasi-optical monopulse antenna. Finally, the structure design of the monopulse antenna is completed, which lays a foundation for the subsequent experimental verification.
【学位授予单位】：东南大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN820

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