最新刊期
卷 ， 期 3 ， 1999
- 摘要：The blind direction-of-arrival estimation implies estimating direction-of-arrival of source signals under the unknown channel structure and responSe and can extensively be aPPlied to wireless communications, radar, sonar and so on.Since the convergence of the existed adaptive blind separation algorithms is dependent on the statistic properties of the unknown source signals, in order to overcome this shortcoming, we propose an efficient algorithm for adaptive blind direction-ofarrival estimation based on the asymptotically convergent analysis for the available adaptive blind separation algorithms. Its handedness and asymptotic stability are given and proved. According to the requirement of the asymptotic stability of algorithm,we select appropriately the nonlinear functions in algorithm. For inhibiting the noise and estimating the number of sources, this algorithm also includes the whitening prccers of signals. The simulation rlts show that algorithm is efficient and robust, and estimates the direction-of-arrival from the source signals with noise.关键词：direction-of-arrival estimation;Blind separation;adaptive algorithm;Asymptotic stability2|183|2更新时间：2025-12-08
- 摘要：A new method is proposed to provide the simultaneous estimation of both the Doppler frequency and the direction of arrival of multiple signals received by a pulse Doppler phased array radar whose array manifold has an unknown structural form. The robustness of the new method is based on a blind beam-forming framework proud in the paper which is computationally efficient and is corn firmed by computer simulations.关键词：High-resolution array processing;Paramerter estimate;blind signal processing2|297|2更新时间：2025-12-08
- 摘要：This paper studies a design method of decentralized signal detection system which consists of adaptive fuzzied local-detectors and a data fusion rule of on-line self-learning weights. The local--detectorS for inaccurate signal parameters are modeled by means of fuzzy sets which can be adapted to change of the inaccurate signal paraxneteres. The data fusion center Where the optimal decision rules are used as objective function can learn the local decision weights on-line. The robustness of the fuzzied local-detectors and the adaptability of the self-learned fusion rule make it true that the detection performance of the decentralized detection system is improved under uncertainty and this system can also process the decentralized signal detection with a unknown parameter of unknown distribution or non-random unknown parameter.关键词：Multisensor fusion;Decentralized detection;Fuzzy information model representing uncertainty;Self-learning fusion rules2|122|6更新时间：2025-12-08
- 摘要：It is found that the reflection error of Mur’s first-order absorbing boundary condition can be cancelled effectively by applying the ABC twice to an electromagnetic field on two diagonally neighboring nodes on the x-t, y-t and z-t planes, according to which a twofold Mur’s first-order ABC（TMFABC） is developed. It is very convenient to apply TMFABC to multilayer structures. The absorption efficiency of TMFABC is obviously better than that of Mur’s first-order ABC and its super algorithm,especially at lower frequencies. A FDTD software using TMFABC has been written to extract the circuit model parameters of transmission lines in high-speed integrated circuits.关键词：FDTD;boundary condition;Reflection;Transmission lines2|60|0更新时间：2025-12-08
- 摘要：Based on the theory of wide electron beam focusing having curvilinea axis, the nature of electrostatic conic lens was studied, and the definitions of fundamontal electron optical parameters of conic lenses in focusing of electrortatic conic lens was studied, and the definitions of fundamontal electron optical pammeters of conic lenses in electrostatie field, such as focal point, focal length etc, were given, in which the principal trajectory having a planar cuive was considered. For example,the relationship between different electrostatic parameters and electron optical parameters of two types of electrostatic conic lens was shown.关键词：Electron optig;Electrostatic conic lens;Curvilinear axis electron beams2|87|0更新时间：2025-12-08
- 摘要：On the basis of Acousto-Optic Correlation technique, aiming at the problem of correlation peak extraction of Time-Integrating Acousto-Optic Correlator （TI AO Correlator）, an experimental system design is presented in this paper. The mathematical model is established, the optic system and experimental circuits are designed, and the correlation peak is extracted sucessfully, while 51. 9dB of systemic gain is achieved.关键词：Acousto-optic interaction;Time-integrating;Correlation peak;Extraction4|62|6更新时间：2025-12-08
- 摘要：The system model, which is set up by queueing service theory in this paper, for CSMA/CD optical fiber bus LAN with heterogeneous environment is mathematically analyzed and evaluated, and the calculating formula Of bus availability ratio, the important performance parameter of LAN, is derived. In addition, the mathematical model is preliminarily verified by GPSS simulating and the ideal result is obtained.关键词：CSMA／CD;光纤;总线LAN;非均匀;分析2|65|2更新时间：2025-12-08
- 摘要：In this paper, a fourth-order cumulant-based estimation method is presental. As the MUSIG-like method,the method can extend the red array to a virtual extensive array. Especially the paper analyses the characterizations of the two extensive arrays in detail. The relative conclusions are got and verified by the simulation experiments.关键词：:DOA;estimation;High-order spectrum;Array extending2|591|11更新时间：2025-12-08
- 摘要：The imaging algorithms available to maneuvering targets can deal only with the targets with first order Doppler variation of scatterers [4]. An adaptive signal decomposition based on Chirplet is given. An imaging algorithm to maneuvering targets with higher order Doppler variation of scatterers based on the decomposition is proposed, which is verified by raw radar data.关键词：Maneuvering targets;imaging;Chirplet2|259|8更新时间：2025-12-08
- 摘要：A multithreshold method for image segmentation based on objects’ character is proposed in this paper. The prior knowledge of the scene is presented in the form of characteristic vectors in the procedure of segmentation, and therefore the image segmentation is converted to the graylevel-geometric space clustering from the graylevel only based clustering. The experiment results show that the method proposed can segment the object which has considerable graylevel variance from complicated scenes.关键词：image segmentation;Geometric invariant;Character mathch2|249|2更新时间：2025-12-08
- 摘要：A scheme of FDTD near-to far-zone transformation for scattering from an object over the curved earth is presented in this paper. With the equivalence principle, the eqUivalent electric and magnetic currents can be obtained from FDTD near fields output boundaries. The fields radiated by these currents in the presence of curved earth are then calculated using the reciprocity theorem and the known ground wave propagation formula of a vertical electric dipole （S. Rotheram,1992）. Numerical results show excellent agreement between this scheme and analytical results. The feasibility of another approximate approach （Q. L. Li et al, 1997）is also tested by this scheme.关键词：curved earth;scattering;FDTD method;near-to far-zone transformation2|168|1更新时间：2025-12-08
- 摘要：In this paper a newly developed helieal coordinates is used to make out the solution of electromagetic fields in the helix gap and calculate dispersion characteristics of tape helix slow wave structure for the first time. Strict boundary conditions for magnetic fields are adopted and are treated rigorouSly by Fourier expansion. boldes, the radial propagation constant of every layer in the dielectric-loaded region is differentiated. Some of practical tape helix slow wave structures have been calculated for dispersion characteristics and the calculated values accord with measured values very well. The authors also compare the calculated results with experiments for different structures by changing tape thickness or other structure parameters and find that the theory in the paper is universal.关键词：Helical coordinates;Tape helix;dispersion characteristics2|111|5更新时间：2025-12-08
- 摘要：This paper solves the canonical equations for a ray path in arbitrary ahere using difference method, and makes corrections practically for the refraction errors of positioning with monopulse radar and positioning and velocity-measuring with trilateration radar.关键词：Correction for refraction error;Canonical equation for ray2|211|6更新时间：2025-12-08
- 摘要：Long term stability is the main factor that influences the minimum detestable signal of microwave radiometers. Two new types of microwave radiometer are develoed: a computer gain Compensative microwarve radiometer and a continuously calibrated microwave radiometer. The long term stability of both designs is optimal because they are insensitive to system gain fluctuations. The continuously calibrated microwave radiometer is also insensitive to system noise fluctuations. The minimum detectable signals are 0. 13 and 0. 19K respectively under an integration time of 0. 6s.关键词：microwave radiometer;Radio telescope;Computer gain compensative microwave radiometer;Continuously calibrated microwave radiometer2|168|6更新时间：2025-12-08
- 摘要：The signal cross-correlation model of the histogram summing to realize the pulse pairing in TDOA （Time Difference of Arrival ） location system is presented in this paper. The reason of the generation of false peaks in the histogram summing process is analyzed.Some methods to eliminate the false peaks to realize pulse pairing and pulse deinterleaving are also poined out finally.关键词：TDOA location;Pulse pairing;Histogram summing;Signal cross correlation2|337|8更新时间：2025-12-08
- 摘要：A new multivalue feedback closed-loop control algorithm for handling and preventing congestion in highspeed networks is proposed and analyzed. The asymptotical stability （oscillation-free） of this algorithm is proved. The issue of optimal parameter design which gives the optimal transient behavior （in the sense that the asymptotic approach to steady state is fastest）, and the optimal steady-state behavior （non-oscillation, maximum of throughput and minimum of delay） is presented. Extensive simulation results show the robustness of the algorithm and the better performance than other multivalue feedback closed-loop control algorithms.关键词：Closed-loop congestion control;Difference-differential equation;ATM network2|48|2更新时间：2025-12-08
- 摘要：In this paper, the maximum traffic of broadband LAN,on condition that the upper limit of system mean response time is given and theoretically analyzed for four-layer protocol model, and the approximate solution is obtained. Meanwhile, the relation between maximum traffic capacity and upper limit of mean response time and the effects of unbalanced input traffic on mean response time are discussed by numerical examples.关键词：Broadband LAN;response time;traffic2|25|0更新时间：2025-12-08
- 摘要：In this paper, the frequency selective reflection characteristics of dielectric periodic structures for the oblique incidence of a plane wave are analyzed by a method which combines the multimode network theory with the rigorous mode matching method. The variations of the total reflection frequency lopoints, the total reflection bandwidth and the total reflection lopoint within a certain frequency band with the changes of the thickness of the periodic layer, the thickness of the added uniform layer and the dielectric constant of the layer are also analyses. Moreover, the relationship between the related wave phenomenon and the dispersion characteristics of multilayer plane dielectric structure is explained using the theory of planar dielectric waveguide.关键词：frequency selective surface;dielectric periodic structure;multimode network;Total reflection2|131|2更新时间：2025-12-08
- 摘要：A kind of 2-D Unitary ESPRIT method is proposed for use in conjunction with a uniform centro-symmetric array （UCSA）. It is a new closed-form high resolution algorithm to provide automatically paired source azimuth and elevation estimates. In the final stage of the algorithm, the real and imaginary parts of the ith eigenvalue of a matrix are one-to-one related to the respective direction cosines of the ith source relative to the x and y axes. Except for the initial transition and the final eigenvalue decomposition of dimension equal to the number of sources, it is efficiently formulated in terms of real-valued computation throughout It can operate in a reduced dimension in DFT beamspace, and reduce computational complexity. The asymptotic performance of the algorithm is presented. Simulation results are presented verifying the efficacy of the method.关键词：Closed-form 2-D angle estimation;2-D Unitary ESPRIT;Uniform centro-ssymmetric array;Automaticaliy pair2|133|1更新时间：2025-12-08
- 摘要：In this article, the specialt y of pseudo-random code CW（PRC-CW） radar was firstly discussed, then we analyzed the statistical characteristics of some typical land clutter. In accordance with the problem of time spread of echo signal under the condition of low grazing angle, we proposed a superposition method to get real clutter echo of PRCCW radar.Through the computer simulation, we find out the model of pdf （probability density function） after superposition.关键词：Pseudo-random code;CW radar;Weibull clutter2|183|5更新时间：2025-12-08
- 摘要：The radiating properties of a linear dipole antenna loaded by lumped resistors are firstly calculated by 3-D FDTD method. The current waveforms on the antenna are given. The influence of the loaded lumped resistors and the parameters of lossy media on the current waveforms is also calculated and analysed. The pseudo-color pictures of the objects buried in different media are calculated by 2. 5D FDTD methed. The comparison between the result obtained by FDTD method and that by our Ground Penetrating Radar （GPR） system is made,and excellent agreement is obtained. The parameters of lossy media to influence the detectable depth and the resolution of GPR are studied.关键词：FDTD method;Carrier-free ground penetrating radar;Linear antenna loaded by lumped resistors;Transient radiating and scattering poperties2|218|2更新时间：2025-12-08
- 摘要：The multistep sparse technology （MST） is described in this paper. Using multistep amplitudes （including 0 and 1） the prescribed array can be thinned. Compared with the statistic density tappering technology （only using 0 and 1 ）,MST can improve the sidelobe level of the sparse array obviously. Here, with the help of the Probability Theory and the Optimum and Consistent Aproaching Method, MST is presented in details and the probability of the peak sidelobe level less than the given value is given.关键词：sparse array;Multistep sparse technology;Sparse parameter;Peak sidelobe level;Average value;variance4|196|21更新时间：2025-12-08
- 摘要：A UTD（Uniform Geometrical Theory of Diffraction） is developed for the HF electromagnetic radiation and diffraction field from slot on a conducting convex surface coated with a dielectric layer. With the aid of the caonical problem UTD solution, the dyadic transfer function（DTF） between the source and the radiation（or diffraction） field is derived for the problem. The radiation and diffraction field are expressed by compound Fock’s functions （CFF）. The compound Fock’sfunctions reduce to the geometrical optics field in the deep lit region and are deseribed by creeping waves in the shadow region and also remain uniformly crossing the boundary between lit and shadow region.Some numerical results based on the UTD solution are given and shown to agree well with experiments or exact results.关键词：Conducting convex surface with a dielectric coating;Uniform geometrical theory of diffraction;Dyadic transfer function2|88|5更新时间：2025-12-08
- 摘要：Propagational properties of parallel ferrite and dielectric slab loaded speific waveguides are analyzed by using combining methods of lines and transverse resonance. The results indicate that the ferrite loaded ridged waveguide has broadband frequency properties and the grooved waveguide has greater differential phase shift suitable for making the high figure of merit phase shifters.关键词：Specific waveguide;Method of lines;ferrite;Dielectric slab2|47|1更新时间：2025-12-08
- 摘要：The wide band characteristics of millimeter wave can be applied for solving many problems on wide band wireless access. This paper presents the basic concept of indoor radio wave propagation at first. Then it introduces and analyzes recent works on the millimeter wave indoor propagation, including the millimeter wave characteristics of construction material, the measurement and simulation of millimeter wave indoor propagation.关键词：millimeter-wave;Wide-band wireless access;Construction material characteristics;Indoor propagation measurement;computer simulation2|297|3更新时间：2025-12-08
- 摘要：Space-time adaptive processing （STAP） is a crucial technique for the new generation airborne radar. In this paper, the status of space-time adaptive processing for airborne radar is reviewed, in which some of our work are included.Some frontiers and related problems on STAP are also discussed.关键词：airborne radar;Space-time adaptive processing;clutter suppression4|598|2更新时间：2025-12-08
- 摘要：Thsi paper deals with the profile reconstruction of the incomplete data from the deep Induction Tool （6FF40） using the distorted Born iterative method （DBIM） and an efficient numerical mode-matching （NMM） method for the conductivity distribution in a two-dimensional axisymmetric medium. In each iteration of DBIM, ill-condition problem can be improved by using the Tikhonov regularization method. NMM is applied to solve a forward solver. Meanwhile, the analytic expression of the integration in the nonlinear integral equation has been derived and then both the inversion of the efficiency and the accuracy improved dramatically. Some numerical simulation examples show that this method is useful for the interpretation of electrical logging data.关键词：Efficient Inversion;Deep induction tool;Poor information;DBIM;NMM2|65|3更新时间：2025-12-08
- 摘要：Based on typical array geometry and the flexible definition of fourth order cumulant of array output signal, a novel method for estimating multiple spatial narrow-band signal 2-D directions of arrival is presented in this paper. Without spectral peak searching and pairing among parameters, it can greatly reduce array aperture and be employed to arbitrary Gaussian noise environment. Computer simulation confirms its availability.关键词：array signal processing;Azimuth;elevation;Fourth order cumulant2|200|9更新时间：2025-12-08
- 摘要：This paper presents a new method named Optimal Beamforming Matching Method, which realizes high-resolution bearing estimation using the output of beams. It can efficiently estimate the direction-of-arrival DOA of multiple targets through beamforming system and can deal with complete coherent sources. Monte Carlo test shows its stable performance and promising application.关键词：DOA;High-resolution technique;Beamforming system2|144|3更新时间：2025-12-08
- 摘要：In this paper, a novel method of matched correlation for high range resolution polarization radar target recognition is presented. At first the theory of multiple-polarized range profiles recognition using matched correlators is introduced.Then the approach to construction of multi-dimensional matched correlators is given. At last experimental data of radar targets are used to test the performance of the method. Theoretical analysis and experimental result show that effectual use of polarization information can enhance the performance of radar target recognition.关键词：radar target recognition;polarization;Range profiles;Matched correlators2|230|6更新时间：2025-12-08
- 摘要：In this paper, the analysis of broadband interaction and harmonic suppression is presented. A special dispersion shape used in broadband TWTs is obtained, and the theoretical and experimental studies of dispersion shaping are given.On the basis of these studies, a broadband high power TWT is designed. In the frequency range 6. 518GHz; the output power is 180 watts at band edge and 250 watts at mid band. The gain is greater than 35dB.关键词：broadband;TWTs;Metal loading;Dispersion shaping;harmonic suppression2|136|4更新时间：2025-12-08
- 摘要：The quantization precision is determined by the word-length of analog-to-digital converters. But by adding noise to the signal before quantization and averaging a set of quantization results, the quantization error can be reduced. A strictly mathematical analysis is given in this paper. The conditions for unbiased estimation and the minimum sampling number needed in averaging in order to reach a given quantization precision are given. Particularly, the performances using Gaussian noise and uniform distribution noise as the additional noise are analyzed and compared in detail.关键词：quantization;precision;noise;Finite-word-length2|77|3更新时间：2025-12-08
- 摘要：The coventional clutter map CFAR method is often used to detect targets in a temporally stationary and spatially nonhomogeneous background. It averages radar returns temporally over several radar scans to form estimates of the mean background level for each clutter map cell. so it’s called as clutter map CFAR point technique. A new approach of clutter map CFAR plane technique was proposed by Shen Fuming[1], which can be applied in a temporally and spacially homogeneous background. and is called plane technique. An analytic expression of detection performance of this technique is derived, and a performance comparison to clutter map point method is also given. It’s shown that the performance of plane technique is superior to that point method in a temporally and spatially homogeneous background.关键词：radar;detection;CFAR;clutter map2|376|4更新时间：2025-12-08
- 摘要：In this article, converted measurement kalman filter （CMKF） is inferred in 3-dimensional space. A target tracking application is simulated to compare the converted measurement KF and extended kalman filter（EKF）. The result is that CMKF has a higher accuracy than EKF.关键词：Converted measurement kalman filter;Extended kalman filter;Radar target tracking2|1147|24更新时间：2025-12-08
- 摘要：A Ka-band frequency synthesizer based on mm-wave harmonic mixer as well as IF PLL is described in this paper. The synthesizer design together with its implementation is illustrated. The main specifications of the prototype mmwave synthesizer are: frequency range: 26. 5 40GHz, out-put power: > + 5dBm, resolution: 1MHz, phase noise: （10KHz） <-65dBc/Hz, phase spuriousness: < -55dBc.关键词：Freuqency synthesizer;mm-wave signal source;phase noise;Phase lock loop2|190|14更新时间：2025-12-08
- 摘要：In this paper, a novel phased array radiating element for use in wide-angle scanned plannar slot array is discussed. The important problems in array design-characteristics of asymmetric single ridge waveguide are studied with FD-TD method. Some waveguide properties such as electromagnetic field distribution.travelling wavelength and radiation characteristics are obtained. Furthermore. the relationship between alers characteristics and the degree of asymmetric is founded. The results are investigated for the design of wide-angle scanned planar slot phased array.关键词：Asymmetric single ridge waveguide;FDTD;slot antenna2|161|1更新时间：2025-12-08
- 摘要：Finite Element Method （FEM） was first applied to calculate the impedance and resonant frequency of a thin substrate rectangular antenna with tuning post. The results of the resonant frequency are in agreement with the experimental data very well. In principle, this method is applicable to the antenna with many tuning posts in arbitrary places. Perhaps this method is the best one for analyzing the rectangular antenna with tuning posts.关键词：矩形贴片天线;谐振频率;输入阻抗;调谐销钉;有限元2|216|1更新时间：2025-12-08
- 摘要：FDTD method has been widely studied and applied in the recent years. It has many advantages over other numerical methods. When CAD technique gets involved,FDTD method makes a large pace toward its practicableness. In this paper,we introduce how to use CAD software to generate the original geometreic-electromagnetic parameter description file provided to the FDTD calculation code to solve the electromagenetic scattering problem of those objects with complex geometric shape and electromagnetic parameter distribution. Using this technique, we can get the geometric-electromagnetic parameter description file from the design drawing, sectional drawing or other ways of description of the objects. As an example, a kind of plan’s RCS in the resonance frequency was calculated.关键词：FDTD;CAD;RCS;electromagnetic scattering;Complex object2|373|5更新时间：2025-12-08
- 摘要：A new method of full-wave analysis for arbitrary guiding structure using a symmetrical condensed node TLM is developed. The numerical results confirm that the method retains all the characteristics of the 3-D analysis, but requires much less memory space and CPU-time.关键词：Electromagnetic wave simulation;TLM;Wave guide2|55|3更新时间：2025-12-08
- 摘要：In this paper we discuss a kind of multitarget tracking and association method based on data fusion of heterogeous multiple feature data gained by a sensor such as space state,signal amplitude,Doppler frequency and so on. We define a correlation measure which we explain as the generalization of conventional association decision.Correlation measure can take any real value from 0 to 1 to represent the extent Of correlation. Considering the practical circumstances that some feature data might not be easily gained successively, we introduce an effective factor to deal with the cases. In the paper we also discuss the association results by comparison of computer simulation tests.关键词：Feature data;data association;target tracking5|521|10更新时间：2025-12-08
- 摘要：This paper proposes a new way to calculate the influence of electrode perturbation on particle trajectory. In terms of variational principle, the derivative of potential versus electrode displacement is computed first. Then the derivative of practical trajectory is calculated and the influence of electrode perturbation on trajectory is obtained. Compared with old method, this algorithm can improve the computational accuracy and efficiency.关键词：Electrode perturbation;Charged particle optical system;Particle trajectory4|69|3更新时间：2025-12-08
- 摘要：An instability of a cold, relativistic beam of electrons gyrating in a combined solenoidal and longitoudinally polarized periodic wiggler magnetic field interacting with a peniotron electromagnetic field is studied. It is shown that the instability works at the hybrild frequency of ω≈ωc+kwv, and its working mechanism is based on the peniotron’ s. Therefore,this device has merits of both high frequency and efficiency. An efficiency of 36% is found in computational calculations. Furthermore, its output power is adjustable with the wiggler field.关键词：Free electron laser;Peniotron;efficiency2|28|0更新时间：2025-12-08
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