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宽带光延迟移相网络波束形成技术研究

发布时间:2018-03-24 10:47

  本文选题:光控相控阵 切入点:波束形成 出处:《电子科技大学》2014年博士论文


【摘要】:光控相控阵天线具有宽带宽角的技术特点,成为相控阵天线领域的研究热点。光延迟移相网络作为相控阵天线波束形成的核心部件,实现了对微波信号在光域的延迟移相和合波,克服了“孔径效应”和“渡越时间”对带宽的限制。光延迟移相网络的技术指标将直接影响相控阵天线空间波束形成的性能,因此,研究宽带、高精度、多波束的光延迟移相网络对实现高性能的光控相控阵天线具有重要意义。论文详细分析研究了光延迟移相网络的各种拓扑结构和实现方案,针对光控相控阵天线的工程应用,采用磁光开关、单模光纤、光分路器、波分复用器等器件,提出了满足宽带、高精度、多波束要求的光延迟移相网络拓扑结构,完成了实施方案的设计和关键技术参数的分析计算。采用相控阵波束形成理论和统计理论,推导了光延迟移相网络延迟误差和幅度误差与空间波束电平指标之间的理论关系式。基于光传输链路噪声理论,推导了模拟光收发模块噪声系数、输出信噪比、链路关键光电参数与空间波束电平之间的理论关系式。对上述理论推导结果进行了仿真研究,仿真结果表明:光延迟移相网络延迟误差对空间波束指标劣化起主导作用,幅度误差仅对副瓣电平影响较为明显;光载波传输链路中,束指向误差均方差与链路噪声系数的1/2次方成正比,与阵元数的3/2次方成反比;链路中激光器相对强度噪声、链路插入损耗、激光器输出平均光功率是导致空间波束指标劣化的主要因素,这些参量劣化均会导致波束主瓣指向误差增大和增益降低,副瓣出现电平升高,其中激光器相对强度噪声影响最为明显。当激光器相对强度噪声低于-140dB/Hz,链路插入损耗小于10dB,系统性能较佳。针对光延迟移相网络延迟时间的精确测量,采用相干长度包络顶点检测技术,设计了基于M-Z干涉仪相干零位检测的光纤长度测量系统,测量精度达到亚皮秒量级。同时,研制了高精度光纤切割工艺平台,实现10μm级切割精度。基于上述测量平台和工艺平台,完成了高延迟精度的波分复用延迟线和5bit磁光开关延迟线的研制,其中延迟误差均方差分别达到0.14ps和0.62ps,幅度一致性达到0.13dB和0.32dB。针对16阵元宽带(2~6GHz)相控阵接收线阵,研制了高精度宽带多波束光延迟移相网络。该网络包含256条延迟链路,在空间形成了15个固定波束和1个可变波束,主要技术指标为:固定波束和可变波束无源网络延迟误差均方差分别优于0.16ps和0.63ps,插入损耗误差均方差优于0.18dB和0.34dB,波束内光收发模块幅度误差均方差优于0.65dB,相位误差均方差优于1.96°。光延迟移相网络实现了高精度的延迟时间和幅度一致性,满足了相控阵天线的应用需求。
[Abstract]:Optical phased array antenna has the characteristics of wide wideband angle and has become a research hotspot in the field of phased array antenna. Optical delay phase shift network is the core component of phased array antenna beamforming. The delay phase shift and wave of microwave signal in optical domain are realized, and the limitation of bandwidth caused by "aperture effect" and "transit time" is overcome. The technical specifications of optical delay phase shift network will directly affect the performance of space beamforming of phased array antenna. Therefore, it is important to study the broadband, high-precision, multi-beam optical delay phase-shift network for the realization of high performance optically controlled phased array antenna. In this paper, various topologies and implementation schemes of the optical delay phase-shift network are analyzed and studied in detail. Aiming at the engineering application of optical phased array antenna, the optical delay phase shift network topology is proposed by using magneto-optic switch, single-mode optical fiber, optical splitter, wavelength division multiplexer and other devices, which meet the requirements of broadband, high-precision and multi-beam. The design of the implementation scheme and the analysis and calculation of the key technical parameters are completed. The phased array beamforming theory and the statistical theory are adopted. Based on the theory of optical transmission link noise, the noise coefficient of analog optical transceiver module and output signal-to-noise ratio (SNR) are derived. The theoretical relationship between the key optoelectronic parameters of the link and the level of the spatial beam is studied by simulation. The simulation results show that the delay error of the optical delay phase shift network plays a leading role in the deterioration of the spatial beam index. In the optical carrier transmission link, the mean square error of the beam pointing error is proportional to the 1 / 2 power of the link noise coefficient, and is inversely proportional to the 3 / 2 power of the array element, and the relative intensity noise of the laser is in the link. Link insertion loss and laser output average optical power are the main factors leading to the deterioration of spatial beam index. These parameters will lead to the increase of beam main lobe pointing error and the decrease of gain, and the increase of sidelobe level. When the relative intensity noise of laser is lower than -140 dB / Hz and the link insertion loss is less than 10 dB, the system performance is better. Based on the coherent length envelope vertex detection technology, a fiber length measurement system based on M-Z interferometer coherent zero position detection is designed. The measuring accuracy is in the order of sub-picosecond. At the same time, a high-precision optical fiber cutting technology platform is developed. Based on the above measuring platform and process platform, the high delay line of wavelength division multiplexing (WDM) and 5bit magneto-optic switch delay line are developed. The RMS of delay error reaches 0.14ps and 0.62psrespectively, and the amplitude consistency reaches 0.13dB and 0.32dB. for the 16 array wideband wideband array receiving line array, a high-precision broadband multi-beam optical delay phase-shifting network is developed. The network consists of 256delay links. There are 15 fixed beams and 1 variable beam in space. The main technical parameters are as follows: the mean variance of delay error of fixed beam and variable beam passive network is better than that of 0.16ps and 0.63 pss. the mean variance of insertion loss error is better than that of 0.18dB and 0.34 dB, the mean variance of amplitude error of optical transceiver module in beam is better than 0.65 dB, and the phase error is wrong. The difference mean square deviation is better than 1.96 掳. The optical delay phase shift network achieves high precision delay time and amplitude consistency. The application requirement of phased array antenna is satisfied.
【学位授予单位】:电子科技大学
【学位级别】:博士
【学位授予年份】:2014
【分类号】:TN821.8

【参考文献】

相关期刊论文 前1条

1 邱志成;史双瑾;邱琪;;高精度光纤延迟线的研究[J];光电工程;2009年06期



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