Mutual Interference of Millimeter-Wave Radar Systems

This paper examines the probability that any millimeter-wave radar systems will interfere mutually by considering spatial, temporal, and operational frequency-related overlaps. It examines the nature and magnitude of the interference under different conditions and for different sensor types before concluding that in an overlapping frequency band, the probability that interference will occur is high. It goes on to demonstrate that, though there are some forms of interference that can be identified and controlled, there are others which are impossible to isolate, resulting in degraded target detection performance and tracking     

射频干扰对消技术抗单音干扰性能分析

传统的抗射频阻塞干扰方法会引起有用信号的畸变,同时仅部分抑制了射频阻塞干扰。为了解决这些抗干扰方式存在的不足,提出了一种解决方案射频干扰对消,给出了射频干扰对消抗阻塞干扰的实现方法,并对其抗单音干扰的性能做了计算仿真。结果表明,采用射频干扰对消技术后,在Eb/N0相同的条件下,干信比在10~30dB范围内,对误码率没有影响。     

On the Generation of Mutual Interference Matrices

This paper is concerned with the presentation of an algorithm for the construction and display of a mutual interference chart of any size from a list of interference lines belonging to any paired transmitter and receiver. Such charts have found use in procedures for assignment of noninterfering frequencies in a communication network. This algorithm is primarily concerned with the interpretation and conversion of lines of interference, having an arbitrary width, from a continuous frequency space to a discrete integer space represented by a mutual interference chart. The widths of the interference lines are related to equipment frequency guardbands. The discrete integer space is related to equipment channel and band numbers. The method of construction is proved to be consistent with respect to element value assignments.     

IR-UWB技术互干扰性及DAA技术的研究现状

超宽带（UWB：Ultra—widthband）是指信号的一10dB相对带宽超过中心频率的20％,或一10dB绝对宽带超过500MHzI“。UWB通信系统作为一种新颖的室内短距离无线电通信系统正在受到广泛的关注。     

编队中雷达互扰模型研究

舰艇组成编队时,雷达间可能有新的干扰产生,需要对编队雷达进行互扰预测分析。给出了雷达间干扰产生的条件,并建立了编队互扰预测模型。该模型考虑到了影响编队中不同舰船平台上雷达互扰的所有因素,能够较精确地对编队中雷达互扰进行预测。     

Coaxial Cables as Sources of Intermodulation Interference at Microwave Frequencies

Intermodulation interference arising from nonlinearities in braided coaxial cables at microwave frequencies is discussed. Detailed investigations have been carried out using a large number of commercially available and specially constructed cables to isolate and assess the relative contributions of different parameters of coaxial cables responsible for the generation of intermodulation products (IP's) at L-, S-, and C-band frequencies centered on 1.5, 3, and 5 GHz. Ambient temperature in the case of polythene dielectric cables and oxides on copper-wire braids affect considerably the IP's generated in a coaxial cable.     

谐振腔本征值问题的多极理论分析

本文给出用多极理论分析谐振腔本征值问题,以及用多极理论分析谐振腔本征值问题的使用规则。通过数学分析,导出用多极理论分析谐振腔本征值问题的计算公式。实例计算结果表明：用多极理论分析谐振腔本征值问题不仅具有较高的计算精度,而且可方便地应用电磁工程问题的设计与计算,是一种有效的谐振腔本征值问题分析方法。     

不同频率位置的窄带干扰对DSSS通信性能的影响分析

衡量窄带干扰抑制算法性能高低的一个主要标准是评估干扰处于最恶劣频率位置时的干扰输出平均功率的大小。在扩频序列周期很长且严格平衡的理想条件下,最恶劣干扰的频率位置为DSSS信号载波频率。基于典型的m序列DSSS系统,分析了处在不同频率位置的窄带干扰对DSSS系统的影响,所得结果与理想条件有所不同,这对于扩频系统的设计与应用具有指导意义。     

Suppression of Time-varying Multi-tone Interference Based on Frequency Domain Interference Detection

Existing active multi-tone interference (MTI) suppression methods used in direct sequence spread spectrum (DSSS) consider the interference to be time-invariant. However, in most practical scenarios, the interference is time-varying. These conventional analytic models cannot be directly applied to current realistic systems with time-varying interference. Hence, in this paper, we propose a novel approach based on frequency domain interference detection to suppress MTI experiencing a time-varying fading channel. Our approach operates in two steps. Firstly, we calculate the interference decision threshold by the probability of false alarm based on the Neyman-Pearson (NP) criterion. Secondly, we consider that the frequency bin is corrupted by interference, and the corresponding point is set to zero if the magnitude of the received signal exceeds the threshold. The simulation results demonstrate that our proposed method can mitigate time-varying MTI effectively, and can approach the interference-free performance limit over practical ranges of interference power levels and mobility levels.     

Frequency Control of a Resonant Radio Absorber with a Free Space

Journal of Communications Technology and Electronics - Abstract—Numerical calculations of the matching of a resonant radio absorber (RA) have confirmed that the ideal matching of such an RA...     

面向车载应用的混沌激光成像雷达抑制交叉干扰实验研究

激光雷达已经成为无人智能车必备的环境感知设备.现有基于脉冲测距体制的车载激光雷达极易受到其他车载激光雷达的交叉干扰,导致雷达虚警和误判,引发交通事故.文章利用布尔混沌信号调制激光器产生的混沌激光作为雷达探测信号,结合扫描成像技术,构建混沌激光成像雷达系统,实验实现了 目标物体的三维成像,并对其抑制交叉干扰的能力进行了实验测试.实验结果表明,在不采取任何抑制干扰措施的前提下,基于布尔混沌雷达波形的正交性,仍可在高强度干扰下实现探测目标的三维重构,有效抑制交叉干扰的影响.     

全频段导航压制干扰信号产生技术研究

随着卫星导航技术高速发展,卫星导航装备已广泛应用于军事、交通、金融、电力等诸多领域,国内相关场所建设了一些卫星导航欺骗攻防测试环境,但是,对于全频段卫星导航压制干扰技术,国内研究较少。同时,我国北斗系统建设及导航工程应用实际表明,针对导航系统,尤其是针对导航服务频段的有意、无意干扰越来越严重,涉及单载波、脉冲、扫频、宽带白噪声及其组合干扰等多种干扰类型。通过对卫星导航压制干扰信号产生技术开展相关的研究工作, 以支撑压制条件下的卫星导航攻防测试环境构建。     

Mutual Coupling Between Box-Horn Elements of a Phased Array Terminated in Three-layered Bio-Media

The ldquoplane wave spectral techniquerdquo is used to investigate theoretically the extent of mutual coupling between two box-horn elements of a phased array terminated in three-layered bio-media (skin, fat, and muscle layers). The results obtained have been validated against published results in the literature. Each box-horn of the array is assumed to be filled with water to provide good impedance match to the bio-media. Also, it reduces the dimensions of each box-horn which makes it suitable for array configuration. The effects of relative position of elements, spacing between elements, frequency, aperture size of each element, relative phase and amplitude of excitation of the elements on mutual coupling coefficients are numerically investigated and presented for an array of two box-horns terminated in bio-media. The specific absorption rate (SAR) distributions along the direction of the array axis in muscle layer of the bio-media in direct contact with a collinear array of two box-horns both with and without mutual coupling considerations are also computed and presented. The results of the present research work can provide useful design guidelines for the development of prototypes of box-horn array for hyperthermia treatment of tumors. Bio-media, box-horn, hyperthermia, mutual coupling, phased array, plane wave spectra.     

电磁干扰中元件的高频特性研究

电力电子设备产生的电磁干扰都会超过可接受的水平,所以要利用滤波电路降低他们产生的EMI,这些滤波电路由串联扼流圈和并联电容器构成低通滤波器,文章对EMI滤波元件的高频特性进行分析,给出了电容、电感、电阻等的高频特性、等效电路以及仿真曲线。得出的结论体现出与工频下不同的特性,对滤波设计有重要指导意义。     

Interference and Sharing at Medium Frequency: Skywave Propagation Considerations

A considerable amount of work dealing with nighttime skywave propagation has been done; however, some areas remain to be explored. For example, short-term variation of field strengths has been overlooked. Daytime propagation is far from being quantitatively understood. Also, it is not quite possible to determine interfering signal levels which may be present for a small percentage of time with high accuracy. During sunspot cycles 18 and 19, the Federal Communications Commission conducted an extensive field-strength measurement program in the midlatitude areas of North America. These and other data are revisited with a new emphasis, namely interference and sharing. This paper discusses, among other things, determination of field strengths exceeded for different percentages of time (1 to 99%), diurnal variation of field strengths, favorable conditions for daytime skywave propagation, effect of magnetic storms, frequency dependence as observed at daytime and nighttime. *Views and opinions expressed in this paper are those of the author and should not be interpreted as official FCC policy.     

Frequency assignment: Theory and applications

In this paper we introduce the minimum-order approach to frequency assignment and present a theory which relates this approach to the traditional one. This new approach is potentially more desirable than the traditional one. We model assignment problems as both frequency-distance constrained and frequency constrained optimization problems. The frequency constrained approach should be avoided if distance separation is employed to mitigate interference. A restricted class of graphs, called disk graphs, plays a central role in frequency-distance constrained problems. We introduce two generalizations of chromatic number and show that many frequency assignment problems are equivalent to generalized graph coloring problems. Using these equivalences and recent results concerning the complexity of graph coloring, we classify many frequency assignment problems according to the "execution time efficiency" of algorithms that may be devised for their solution. We discuss applications to important real world problems and identify areas for further work.     

自由空间微光学元件的研制

介绍了一种新近产生的被称为自由空间微光学平台（ Ｆ Ｓ Ｍ Ｏ Ｂ）的三维空间集成光学系统。并提出了一种用二氧化硅（ Ｓｉ Ｏ２）作光学材料、光刻胶和溅射铜（ Ｃｕ）薄膜作牺牲层、电镀铁镍（ Ｆｅ Ｎｉ）作支撑结构的制作自由空间微光学元件的新工艺。研制成功了多种与基底相垂直的三维位相型微光学元件。     

利用时频分析抑制射频干扰

提出了一种适合于线性调频体制射频干扰滤除的方法,该方法基于短时傅立叶变换(STFT)的基本原理。针对单一频率的射频干扰在线性调频体制中非平稳性和瞬时性的特点,利用STFT 对含干扰的信号进行分析,并且在时频分布上利用特征值分解的方法得到信号子空间和噪声子空间,利用信号子空间构造投影矩阵滤除射频干扰的影响。经过实测数据的检验,信噪比提高了近10 dB,表明该方法能有效地解决射频干扰的抑制问题。     

用MOM-UTD混合方法计算共形天线阵单元间的互耦

采用矩量法(MOM)结合一致性绕射理论(UTD)来计算共形天线阵单元间的互耦。这种混合方法通过UTD来修正MOM中的广义阻抗矩阵将理想导体曲面对天线的影响考虑在内。克服了单独采用这两种方法的缺点。既减少了计算量又达到了一定的精度。计算结果与文献中已有的结果吻合得相当好。     

强干扰下跳频信号的提取

强干扰存在的情况下,跳频信号检测和特征提取十分困难,为此,结合图像处理和噪声峰值提取的思想,提出了完整的提取跳频信号特征的方法:以短时傅里叶变换时频谱为基础,改进了一种利用形态学图像处理估计噪声基底的方法来消除噪声;然后,对每个时刻的频谱估计出信号个数和对应频率,根据统计的所有时刻的各类信息,将干扰信号排除,得到跳频信号.仿真实验表明,该方法能够在强干扰存在时,检测出幅度较弱的跳频信号,具有较好的抗强干扰性能.