大阵面天线液压折叠技术研究与实现

为了实现对大尺寸平面阵列天线的公路和铁路快速运输,把大阵面天线分割成相互独立而又连接的上下2个阵面.系统采用液压控制技术和伺服控制技术,以液压回转缸作为天线展开/折叠的驱动执行机构,以可编程控制器PLC为伺服控制器,实现天线自动展开、折叠与锁固.试验及实践表明:该系统性能稳定,操作简单,阵面重复面精度高,锁定简单可靠,具有广阔的应用前景.     

用于交通信息检测的开关天线阵列雷达研究

针对智能交通系统日益复杂而精确的交通信息检测需求,本文提出基于开关天线阵列的交通信息检测雷达,介绍了其系统组成、工作原理以及信号模型和处理流程。该雷达采用调频连续波体制,可同时准确检测多条车道车流量、车道占有率;利用开关天线阵列技术进行单通道测向,根据目标车辆相对天线的方位角度变化率可准确测量车速、判断车型,而且成本低廉。理论分析和仿真结果表明,开关天线阵列雷达距离分辨率达到0.5米,测角精度小于0.1度(0dB信噪比)。     

ADF在相控阵天线阵设计中的应用

针对商用仿真软件ADF在天线阵列中的应用,对矩形多波束平面相控阵天线建立了天线单元模型和25×25模型的仿真,仿真了该阵列的内部天线单元的增益、轴比等性能,仿真结果表明该软件在阵列天线仿真具有很高的使用价值,对相控阵天线的设计应用具有重要的工程指导意义。     

野外监测折叠无人机

正设计说明:该无人机为大型六旋翼折叠多轴无人机,主要用于野外监测,森林草原防火监测,户外全景视频监控等领域,具有飞行载荷大、滞空时间长、可全景拍摄的特点。旋臂采用三幅折叠结构,每根支撑两个螺旋桨。折叠收缩后可紧密围绕在雷达天线的周围。载荷部分由三组可变焦摄像头实现了360°全景监控,并配备了红外热敏感应装置,     

一种星载Ka频段圆极化振子天线阵列设计

针对Ka频段卫星通信系统的需求,设计了一种应用于卫星通信的星载Ka频段圆极化振子天线阵列.天线单元采用非对称双臂振子单元形式,十字交叉振子采用自相移结构来实现圆极化.天线阵列采用三角形排布的方式,通过调整布阵时天线单元旋转相位,来实现阵列的右旋圆极化.仿真结果表明：天线阵列驻波比除阵面四周由于边缘效应引起的驻波比偏大外,其余都小于1.5;天线阵列的轴比小于2.3 dB;扫描60°时,天线增益下降小于5 dB,表明天线阵列具有较高辐射功率.该天线阵列可作为相控阵天线的馈源,在卫星通信系统具有良好的应用前景.     

X波段32元高增益阵列天线设计与仿真

本文研究了一种X波段32元高增益带状线天线阵的设计方法。阵元排列采用泰勒分布实现低副瓣。通过优化带状线对称振子结构,展宽了阵列天线阻抗带宽。讨论了天线单元结构尺寸与天线阵列带宽之间的关系,介绍了带状线天线阵馈电网络以及带状线转微带接头的工程实现途径。仿真计算结果表明,天线阵列在8%的相对带宽内电压驻波比小于1.4,增益大于20dB,并具有良好的阵列方向图。     

大型数字阵列天线的软件化测试

数字阵列由于其众多的优点使其在雷达、通讯领域都得到广泛的应用。但是阵列天线各种系统的误差,严重影响系统的性能。所以,阵列天线的校正测试十分重要。随着大型天线阵面的发展,成千上万的天线单元增大阵面测试的复杂度和工作量。而专门的测试系统一般开发成本极高,而且不具备通用性要求。虚拟仪器系统开发平台LabVIEW结合通用的数据采集仪器,通过软化设计,编制具有友好人机交互界面的数据采集和监视VI(虚拟仪器),实现阵列天线测试过程中的通道监视、数据采集,最终完成数字天线阵列的测试工作。     

平面等角螺旋天线阵列/树脂复合材料的吸波性能研究

研究了含平面等角螺旋天线阵列复合材料的微波吸收特性,并对天线阵列的吸波机理进行了初步的探讨。结果表明:含平面等角螺旋天线阵列复合材料的吸波性能与天线的起始半径、外半径和两臂间电阻阻值密切相关,经合理设计,吸波材料的有效带宽达6.64GHz,最大吸收峰值-19dB。     

卫星天线一体化轴系驱动机构研究

导航卫星天线指向驱动机构是实现卫星星间链路天线高精度、长寿命可靠指向的核心部件。根据驱动机构需经历的发射段力学环境，入轨后真空、高低温等约束条件及星间链路天线的高精度、长寿命的特殊要求，提出了在步进电机、谐波减速器、编码器串装和一体化轴系的基础上，提高驱动机构精度和寿命的设计方法。理论分析了驱动机构预紧轴系受力状态及其影响因素，并进行了驱动机构轴系预紧力、启动转矩等效试验和使用寿命试验，分析了所设计驱动机构的负载特性；对驱动机构轴系的锁紧螺母进行结构改进，使驱动机构轴系的受力得到了较好的优化。为验证所设计驱动机构及其改进方法的正确性，在地面开展了不同热环境下精度和寿命等测试试验，最终验证了该导航卫星天线驱动机构能够满足天线在特殊环境下高精度、长寿命在轨稳定运行的要求。机构轴系预紧力的分析和试验验证工作具有一定的工程指导意义。     

四连杆机构的合理化设计

介绍一种新型简单的平面四连杆机构的运动综合图解方法，并用实例说明如何用这种方法对水平变幅起重机臂架四连杆机构和自动开门机构进行合理化设计。     

纸箱封装机折页机构的设计与研究

目的 为解决现有的纸箱自动化包装生产线上纸箱封装机的折页机构折侧页不可靠、无法对多规格的纸箱进行折页的问题,设计一种可靠、适用于多规格的纸箱折页机构以提高纸箱包装质量和包装效率。方法 通过对折页功能、纸箱状态和封装机整体进行分析研究,设计2组纸箱折页机构;用机构的动态静力分析方法对2组折页机构进行运动学分析和动力学分析,用Matlab对运动学方程和动力学方程求解;用SolidWorks软件对2组折页机构进行结构设计和三维建模;将所设计的2组折页机构实物组装在封装机上进行现场试验。结果 运动学分析结果表明,2组折页机构带动纸箱页旋转的最终角位移能够准确地使纸箱页完成折叠工作;动力学分析结果表明,2组折页机构所需的驱动力矩和驱动力符合动力元件的力矩和力的使用范围。现场试验结果表明,所设计的折页机构能够对多种规格的纸箱实现可靠的折页工作。结论 该纸箱折页机构能够可靠地完成不同规格的纸箱折页工作,实现了纸箱折页的自动化与柔性化,可在一定程度上提高纸箱包装生产线的包装效率。     

Millimetre-wave monopulse antenna incorporating substrate integrated waveguide phase shifter

A compact planar E-plane monopulse antenna is proposed and realised at 36.5 GHz for millimetre-wave radar or direction-finding system application, which is built on the substrate integrated waveguide (SIW) technology. A phase shifter having a non-uniform SIW width configuration is self-consistently made of a periodically embedded via array and it can achieve good performances over a relative broad bandwidth. A 180deg directional coupler incorporating this proposed phase shifter structure is developed in the design of an integrated feeding network for the monopulse antenna. Four elements array based on the configuration of antipodal linearly tapered slot antenna is designed as radiator, offering a pair of 'sum' and 'difference' beams along the long direction of the substrate. Measured gain of the 'sum' beam is higher than 16 dBi, whereas the zero depth of the 'difference' beam is lower than -38 dB. This type of monopulse antenna presents an excellent candidate in the development of intelligent millimetre-wave directional- finding system.     

Design and implementation of low sidelobe substrate integrated waveguide longitudinal slot array antennas

Low sidelobe longitudinal slot array antennas are investigated based on substrate integrated waveguide (SIW) technology. The design method consists of the characterisation of the radiating element, the synthesis of the linear array and the development of the planar array including a feeding power divider by performing fullwave electromagnetic simulations for the final accurate design. Two planar slot array antennas are fabricated with a normal printed circuit board (PCB) process. Low sidelobe features are verified by the measured results which are in agreement with the simulated results. For an 8 x 8 SIW slot array antenna, the measured sidelobe levels (SLLs) are below 236 dB in the H-plane and below 225 dB in the E-plane with the Gain of 20.3 dB at 9.9 GHz. And for a 16 x 16 antenna, the SLLs are below 230 dB both in the E-plane and H-plane with the Gain of 24.4 dB at 10 GHz. The achieved design goals on the radiation patterns therefore validate the proposed low sidelobe SIW slot array antennas to be valuable candidates for high performance communication and radar applications.     

Radar Interferometric Measurements With a Planar Patch Antenna Array

A planar patch antenna array has been made for radar interferometry. The antenna array consists of 32 rectangular patches on a ceramic loaded teflon substrate. The patches are individually coupled to the microwave electronics in two orthogonal circular polarizations. The radar interferometer is intended for topographic imaging in industrial environment, in this case, a blast furnace producing hot metal for the steel and metal industry. Ordinary imaging techniques with IR or visible radiation are not possible to use due to high temperatures, scattering from dust and particles. A model of blast furnace burden material surface was measured and detected.     

传声器阵列反方法及其对飞机噪声源识别

为了完善飞机气动噪声源识别测量技术,并认识当代大型客机气动噪声源的基本特征,改进噪声源识别的大型平面传声器阵列。该阵列由104个传声器组成,104个传声器在平面中的位置通过计算机优化设计的方法确定。并用数值模拟的方法检验平面传声器阵列的频谱特性。应用此阵列在西安咸阳国际机场对近20个架次的进场着陆飞机噪声源进行试验测量。通过实验验证传声器阵列技术和传声器阵列数据处理软件。     

Modulating and driving system for the application of microelectromechanical system infrared source array

A problem demanding to be solved in the development of microelectromechanical system (MEMS) IR source array has been the driving circuit and system. A method that can achieve the requirements of high driving power, high output efficiency, high voltage precision, voltage compensation, and deep frequency modulation for driving and modulating a MEMS IR source array was proposed. A liner DC steady voltage integrated circuit ADP3336 is used to drive the source array directly with a programmable compensation module ensuring the precision of radiation peak wavelength. And a FPGA as the control core of the system modulates the frequency and width of the driving pulse to control the array coding pattern. The engineering value of the system would be increased with the application of the MEMS IR source.     

面状不良地质体钻孔雷达响应特征及正演研究

依据钻孔地质雷达探测工作中常见的面状不良地质体,利用几何-物理模型分析方法,推导了面状不良地质体的钻孔雷达反射波的传播距离和双程走时公式,研究了不同倾角、不同收发天线距的面状地质体的雷达反射截面特征,分析了面状地质体反射截面倾角随节理裂隙倾角的变化关系,以及钻孔雷达天线收发间距对雷达波传播距离变化的影响。同时,还利用时域有限差分(FDTD)数值模拟方法,对不同宽度的面状不良地质体进行了雷达响应正演研究,为钻孔雷达在岩体工程勘察中的应用及数据解译提供了直观的感性认识和丰富的判读基础。研究钻孔雷达电磁波波在各种地质条件下的传播,对于提高勘察效果和地质解译的准确性具有重要意义。     

Experimental investigation of directional characteristics for ionospheric clutter in HF surface wave radar

The unwanted radar echoes from the ionosphere are collectively called ionospheric clutter. It has proved to be the greatest impediment to achieve consistently good performance in long-range detection of surface vessels and sea-state monitoring for high-frequency surface wave radar (HFSWR). Field experimental data recorded by the HFSWR OSMAR2003 (Ocean State Monitor and Analysis Radar, manufactured in 2003) has been used in detailed investigations of the directional characteristics for this ionosphere clutter, leading to the development of effective mitigation techniques based on antenna design and adaptive signal processing. Particular attention is given to the amplitude and phase relationship among multiple spatial channels for two types of ionospheric clutter. Preliminary experimental results show that the random gain and phase variation of the antenna pattern overhead null destroyed the amplitude and phase consistency among channels. As a result, no significant measured directivity is observed in this type of specular clutter. For the incidence clutter from a lower elevation angle, it is observed that the spread clutter possesses high directivity. A nonlinear receiving array composed of multiple V-shaped antennas without deep and broad null at near-vertical incidence is proposed for adaptive ionospheric clutter suppression