对无临近点信息干涉条纹的参数估计

用广义radon变换可以从运动目标产生的干涉条纹中估计出目标的运动参数和波导不变量。但是当干涉条纹中没有出现临近点时,用此方法估计不出真实值。为了解决此问题,提出了一种新的估计方法。主要过程是先从时频图中提取出干涉条纹轨迹,再去搜索与此轨迹误差最小的最优曲线,此曲线的参数值代表目标的运动参数和波导不变量。仿真和海试结果表明,在干涉条纹无临近点信息情况下,用广义radon变换估计的参数值与真实值偏差很大,但是文中提出的方法仍能估计出较准确的结果。     

真空波导磁场控制型ECR溅射法的实验研究

微波电子回旋共振（delectroncyclotronresonance．ECR）等离子体溅射法是能在低温下制备高质量薄膜的最新镀膜技术．在该技术中,微波输入窗口易受金属粒子污染,导致微波在窗口反射,从而影响装置的正常工作。本文初步探讨了在ECR溅射装置中．采用真空波导与共振腔连成一体,在连接处配置磁轭（纯铁）．通过改变共振腔与波导连接处的磁场分布,能有效的避免微波窗口污染的技术途径,并较细致的研究了该装置的放电特性。     

招贴创意的拓展与整合研究

准确的创意是招贴的灵魂,使受众产生心灵促动和共鸣。文章从以下三方面来阐述美学意义上的创意:1、招贴的属性分析;2、招贴的创意准确性与多样性把握与创意积累探讨;3、招贴创意思维方法的研究。因此得出结论:创意是招贴设计的灵魂,具有内在的气质美,决定着作品的设计感。招贴创意的是通过各种推导方式产生并需要重再推敲和不断完善的过程。     

Waveguide filter with improved stopband response using transversal slots

In this article, the design and realization of waveguide filter with improved stop‐band response is presented. By inserting transversal slots at the proper position of cavities, without disturbing the field distribution of the dominant mode, the second longitudinal resonant modes are radiated out. This caused the out‐of‐band frequency response of the filter to be improved. The validity of the proposed technique is confirmed by comparison between measurement values and simulation results from the finite element method through the commercial software (high frequency structure simulator). Also, to assure electromagnetic compatibility the slot surfaces are covered by absorbing material. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

基于扩展收敛域CORDIC算法的FM信号数字化解调实现

提出一种新的FM信号数字化解调实现方案。该方案在研究CORDIC算法原理和结构的基础上对其收敛域范围进行了扩展,能解调调制指数较大的宽带调频信号,适合在软件无线电中的应用。扩展收敛域CORDIC算法模块免去了传统的CORDIC算法中的预处理和后处理过程,降低了计算的复杂度和系统的硬件资源消耗。通过Matlab系统仿真和Modelsim硬件描述语言仿真,在SNR≥0dB和载波频偏△fc≤100ppm[1]的情况下,均具有较好的解调效果。     

Pattern squint elimination for quad‐ridged conical and pyramidal horn antennas using bended probes

This article describes a new technique for pattern squint elimination of quad‐ridged conical and pyramidal horn antennas by introducing bended coaxial probes. Because of the phase difference and mutual coupling between vertical and horizontal polarizations, the radiation patterns of the conventional quad‐ridged conical and pyramidal horn antennas squint over a wide bandwidth. The proposed technique substantially reduces the phase difference and coupling between the two probes, so a significant improvement in the radiation patterns over the frequency band of 8–18 GHz can be achieved. The designed modified horn antennas are most suitable as a feed element in reflectors of radar systems and EMC applications. The proposed modified antennas have a voltage standing wave ratio (VSWR) less than 2.2 for the frequency range of 8–18 GHz. Moreover, the proposed antennas exhibit high gain, dual‐polarization performance, good isolation, low SLL, low back lobe, low cross polarization, and satisfactory far‐field radiation characteristics for the entire frequency band. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE 2010.     

非线性扩展结构大系统自适应神经网络跟踪控制

针对一类非线性关联大系统在结构扩展时的跟踪控制问题, 提出一种采用自适应神经网络的控制方法. 该方法要求在不改变原结构系统控制律的前提下设计新加入子系统的控制律和自适应律, 使扩展后所有子系统都具有很好的跟踪性能. 这里主要利用神经网络的逼近功能以及Backstepping 技术来设计自适应律和控制律, 通过Lyapunov 理论证明在该控制器的作用下闭环系统的所有信号均是有界的, 并可使系统准确跟踪. 仿真结果验证了所提出方法的有效性.

     

Wideband turnstile junction coaxial waveguide orthomode transducer

A wideband turnstile junction coaxial waveguide orthomode transducer (OMT) is presented in this paper, featuring coaxial waveguide input and orthogonal rectangular waveguide outputs. It primarily comprises of a turnstile junction, bending stepped impedance transformers and power combiners. The symmetrical geometry helps achieve wide operating bandwidth and balanced output phases. The OMT covers the whole Ku band from 12 to 18 GHz, which aims at wideband dual‐polarized signal combination and separation within coaxial‐type multi‐band antenna systems. An experimental prototype is manufactured and the measured results confirm that the reflection coefficient is lower than ?15 dB within the whole band, and the port isolation is better than 35 dB. Turnstile junction coaxial waveguide OMTs can be adopted widely in circular/coaxial waveguide hybrid feeding networks for multi‐band satellite communication/remote sensing antenna systems.     

小型水电站扩容增效技改中同期点和同期方式选择

本文针对目前每个小型水电站扩容增效技改中微机监控设计和改造中必须解决的同期点选择和同期方式确定问题结合相关理论、规范,在总结常规监控方式下同类问题的解决办法基础上结合工程实际提出了切实可行解决问题的方法和依据。     

基于有限差分法求解单脊波导的并行算法研究

有限差分方法广泛应用于求解波导问题,具有易于并行的特点。为了求解大规模多脊波导场结构问题,试图从并行计算的角度提供一种有效的解决思路,给出基本算法,验证一个实例,在基本算法的基础上可进行一些必要的扩展,对求解多脊波导提供参考。