Design and experimental investigation of a multibeam integrated reflector antenna of the millimeter wave band

A multibeam integrated reflector antenna operating in the millimeter wave band is considered. The antenna consists of a radiating array, a planar mirror, and a multichannel feed. The results of simulation of a radiating array of slots in a metal screen are presented. The array is manufactured on the basis of a medium with forced refraction, including a double-slot array, which can radiate along the normal to the array plane. Operation of the array in the multibeam mode is analyzed. It is shown that application of a medium with forced refraction increases the array aperture efficiency in this mode. The results of the design of a planar two-layer mirror are presented and the mirror’s quality indices are estimated. A multichannel radiator designed as an array of planar H-plane horns is studied. The results of simulation of such a radiator with the help of an approximate technique and numerical solution of an electromagnetic problem are considered. The design of the multibeam antenna and its experimental characteristics are presented.     

非球面齐明透镜的设计

鉴于过去文献只对非球面消球差透镜做了分析,根据初级像差理论给出了非球面齐明透镜(同时消球差和彗差)初始结构的求解方法,包括非球面齐明单透镜和非球面齐明双透镜的求解方法;并利用Zemax光学设计软件验证了这种求解方法的正确性.通过大量的计算给出了各种关系曲线,并分析了相对口径与透镜球差的变化关系,这些分析对光学系统的设计都是有益的.     

An experimental study of planar impact of a robot manipulator

An experimental study of planar impact of a robot manipulator with a stationary rigid surface is presented. Using the data collected from a series of experiments, this paper investigates the post-impact behavior for different pre-impact conditions such as the configuration of the robot, the angle and the velocity of impact. A better understanding of the post-impact behavior for various pre-impact conditions can lead to improved control strategies during impacts in robotic manipulation. Potential applications of this study include robotic assembly and contact tasks. Further, this study could be seen as a preliminary experimental work on impact of general kinematic chains.     

An experimental study of collinear and planar arrays

Measurements are described that serve to verify a recently reported new theory of arrays of arbitrarily located parallel elements especially including ones that are collinear and staggered. Since the theory takes full account of the effects of mutual coupling in determining the distributions of current in each element of an array, the experimental studies involved the determination of distributions of current and charge as well as admittances and field patterns. Since the theory should be a good approximation for dipole elements well over a wavelength long, complete measurements are reported for arrays of both half-wave and full-wave elements in collinear and planar arrangements. Experimental and theoretical results are in good agreement.     

Design of aplanatic waveguide Fresnel lenses and aberration-freeplanar optical systems

A modification of the waveguide Fresnel lens design that has phase-shifting zones placed on the curved contour is suggested. It is shown that the selection of a suitable shape for this contour allows coma aberration to be eliminated. Computer simulation results are presented to demonstrate the significant improvement of the optical characteristics for curved contour lenses. The aplanatic homogeneous refracting waveguide lenses are also considered. It is found that thick aplanatic refracting lenses and the proposed Fresnel lenses have field curvature aberration of opposite sign. This fact allows planar optical systems free from low-order aberration to be designed by combining refracting and Fresnel lenses. An algorithm for producing such a system is presented     

光电目标快速捕获系统设计及其实验研究

在空间光通信系统中,终端平台目标光的捕获技术是通信链路建立的一项关键技术。考虑到传统的扫描捕获方式,系统捕获概率低、且耗时长,不利于通讯系统链路建立,因此提出采用GPS 进行目标快速定位,搭配水平和俯仰基准传感器,利用GSM 网进行无线传输,进而辅助APT 系统完成目标捕获的终端技术,并建立了目标快速捕获系统。基于该系统开展了多项实验研究,结果表明:对于固定点捕获,概率可达100%;对于模拟目标运动捕获,当模拟转速增大时,捕获平均时间增大,捕获概率降低,但仍然能维持在60%之上;对于低速动态捕获,也能较好地完成系统链路建立需求。     

Analysis and experimental evaluation of a new planar piezoelectricaccelerometer

The behavior of a new planar piezoelectric accelerometer is investigated, both theoretically and experimentally. The proposed accelerometer is composed of a piezoceramic ring filled, in its inner space, with a seismic mass. The theoretical analysis has been carried out by using a matrix model of the radial symmetric modes of the thin piezoceramic ring, proposed by the authors (1996). The numerical results obtained for the empty ring show that, with the response being constant, the bandwidth increases when the annulus radius increases. On the contrary, by inserting a high-density and stiffness seismic mass, both the response and the bandwidth increase by increasing the percent quantity of the seismic mass. The measurements of admittance and sensitivity, carried out on a test specimen, validate the computed results and demonstrate that the accelerometer is planar. Finally, an accelerometer composed of two of such elements, stacked and connected in parallel, has been realized     

Design and experimental confirmation of a novel switched hyperchaotic system

To generate complex pseudo-noise (PN) sequences for chaos-based communications, this article presents a novel switched hyperchaotic model, which is constructed based on a modified Chen system by introducing a dynamical controller. The system consists of two different hyperchaotic subsystems and can change its behavior randomly via a switching function. Basic dynamical behaviors of the hyperchaotic system are further investigated. Furthermore, the switched system is confirmed by its positive Lyapunov exponents and laboratory measurements by an electronic circuit.     

宽频带多波束天线阵及其RCS的缩减设计

设计了一种工作于P,L波段多波束天线阵,形成的9个波束在方位面实现90°空域范围覆盖。多波束通过模拟延迟线构成的移相网络实现,同时运用小型化技术将移相网络集成到功分网络中。通过印制电路板工艺实现各馈线所需的相移值。阵列单元采用印刷对数周期天线形式,同时在阵列安装座底板上粘贴吸波材料,进而显著缩减了阵列在X,Ku波段的雷达散射截面(RCS)。理论仿真分析及实验测量结果证明,该天线阵不仅具有宽频带、波束方向图特性良好,而且方位面180°范围内平均RCS小于16 m2,满足系统设计要求。     

激光熔覆孔式同轴送粉系统设计及实验研究

为了解决送粉激光熔覆系统中因重力作用发生偏聚及水冷效果差等问题,采用以激光束轴心为中心轴圆周均匀分布送粉孔的方法,没计了一系列孔式同轴送粉喷嘴(主要结构包括激光束通道、保护气体通道、水冷通道、气载送粉通道),从而获得良好的粉末流形态,提高送粉激光熔覆的质量。用该系列喷嘴在竖直(90),60,30和水平(0)等工况下进行粉末汇集性实验,发现粉末汇集效果良好。通过对Ti和Ni粉末、工具钢和等材料进行熔覆实验,送粉系统输送的粉末稳定、均匀,得到的熔覆样品表面光滑、熔覆层组织均匀,熔覆层与基体呈冶金结合。结果表明,孔式同轴送粉系统较好地满足了激光熔覆对送粉喷嘴的要求,并且能用来进行多种元素粉末的材料合成。所开发的送粉系统适用于材料表面改性和熔覆3维制造。     

平面螺旋天线的设计与实现

平面阿基米德螺旋天线具有极宽的工作频带，然而其匹配平衡电路的宽频带实现则较难，尤其是在加反射腔以使其单向辐射时。在4-6GHz范围内仿真并实际制作出了用于某S波段雷达系统单向辐射的平面螺旋天线，给出了设计参数值、仿真结果及实测结果。     

Design and performance of a planar star mixer

This paper describes the realization of a hybrid star mixer as a planar circuit. The mixer has a minimum conversion loss of 5 dB and, for a conversion loss of less than 9 dB, spans over 2.2 GHz in IF bandwidth and 8 GHz in RF/LO bandwidth. The mixer employs a novel, planar balun structure, similar to conductor-backed CPW, that is suitable for realization as a monolithic circuit     

An experimental study of a pulse compression scatterometer system

The ideal scatterometer, operating from either an aircraft or a satellite platform, should be capable of making rapid, accurate estimates of the sea backscatter cross sectionsigmaover as wide a range of grazing anglespsias possible. Efficient operation over a large range of grazing angles is desirable because 1)sigmabehavior for90deg geq psi geq 70degyields rms gravity wave slope information and is an indicator of sea state and 2)sigmabehavior for70deg geq psi geq 0degyields data on surface wind magnitude and direction as well as information about the power spectrum of the sea. A "hybrid" estimation procedure has been developed for pulse compression radars which uses both frequency and spatially decorrelated samples ofsigmato provide an unbiased estimate ofsigmahaving minimum variance over the entire range of grazing angles for which radar reception is not noise-limited.     

Design and quasi-static characteristics study on a planar piezoelectric nanopositioner with ultralow parasitic rotation

This paper presents a particular mechanism design which is inherently inclined to have no parasitic rotation. The flexure-based stage comprises symmetric flexure guiding mechanism and two piezoelectric stack actuators. The layout of the stage is evaluated by finite element analysis, and the results indicate that the proposed design exhibits ultralow parasitic rotation. A prototype of the stage is then fabricated, and its performance is tested. Experimental results show that the stage has a stroke of 500 μm × 500 μm and the crosstalk is less than 1%. The maximum parasitic rotation is ±1.2 arcsec at a stroke of 500 μm.     

基片集成波导双极化多波束天线的设计

提出了一种基于基片集成波导技术的双极化多波束天线设计方法,利用Butler矩阵作为波束成型网络,通过激励成对的正交缝隙辐射单元组,实现双极化多波束辐射特性。通过配置正交辐射单元组之间的相位关系为同相或反相,可以分别实现极化共波束和极化独立波束的多波束辐射特性,从而适应不同无线通信场景需求,利用空间波束分集或极化分集方式提升无线通信容量。最终,在X波段给出了一种基于基片集成波导技术的双极化独立波束的多波束天线设计实例,仿真结果表明该天线阻抗带宽为9.64~10.25 GHz,对4个输入端口分别激励时可实现双极化四波束辐射,波束增益为14 dBi,验证了所提出的设计思想和方法。     

一种小型平面超宽带天线的设计与研究

提出了一种新颖的小型平面超宽带(UWB)天线.该天线由微带槽天线的基本结构变形而来,为获得超宽带频率特性,设计时馈电微带线采用了渐变结构的叉形调谐支节,金属底板的开槽设计成对称多边形.首先通过数值计算来获得最佳的天线几何尺寸,并制作了实际的样品.对天线的反射特性、方向图以及增益都进行了测试,然后利用时域有限差分(FDTD)方法计算了天线收发脉冲信号的保真度.研究结果显示该天线具有良好的超宽带特性.     

海上光电监视系统的设计与研究

介绍了一种海上光电监视系统的总体方案设计思想、系统构成及主要工作原理,总结了系统的主要技术特点,同时对其技术指标目标与作用距离之间的关系进行了讨论。其设计结果满足舰船的探测距离≥15 km的指标要求。该套系统具有体积小、质量轻、功能多等特点,特别适合中小型舰艇的使用。     

THEORETICAL STUDY OF A STRIPLINE PLANAR ANTENNA

Numerical results,of the aperture field,radiation pattern and directivity of a stripline planarantenna element are obtained by the moment method.The difficulty of singularities in the integral equationhas been overcome by a simple shift of the testing functions.