最新刊期
卷 ， 期 9 ， 1998
- 摘要：Some methods are suggested for improving the stability and convergence of thc solution in the inversion methods applied to the reconstruction of tww-dimensionaI axisymmetric inhomogeneous media. First, the stability of solution is improved by the iterative method itself; Second,a hybrid Born iterative methed is protw for improving the stability of solution and enhancing the convergence speed inthe inversion methed; Third, the stability of solution is improved by changing the regularization parameters in the regularization method. The stability and convergence of the solution in the least squarc method are investigated. Several examples are presented to show the superiority of these methods.关键词：Solution stability;Iterative method;least squares method;Regularization parameters2|47|1更新时间：2025-12-08
- 摘要：The characteristic model of interconnects in VLSI is proposed. The model is numerically synthsized in time-domain by nunerical deconvolution technique from response voltage and current waveforms simulated by finite-difference time-domain （FDTD） methed. With this model, the transient response waveforms of the interconnects with any excitatipn and loads can be rapidly obtained by numerical convolution.关键词：Interconnects in VLSI;Characteristic model;Synthesis in time-domian;FDTD method2|48|2更新时间：2025-12-08
- 摘要：The concept of the modified edge and equivalent edge currents（EECs）by the modified edge representation are intreduced. and they are applied to calculate bistatic RCS of obects. A rule to determine the direction of the modified edge is presented based on the geometrical thoory of diffraction （GTD）,which is not considered as an empirical one. EECs by the medified edge only use the modified edge and the classical keller’s diffraction coefficients to obtain EECx out of the keller, and they overcome the ambiguity about definition of EECs at general edge points except for diffraction points. Numerical results show that the rule presented in this paper is reasonable, and that EECs by the modified edge representation posses high accuracy and do not cause additional false singularities.关键词：Bistatic RCS;Modified edge;equivalent edge currents2|140|5更新时间：2025-12-08
- 摘要：The paper presents a new numerical synthesis algorithm, goal pattern iterative algorithm,for antenna arrays. This algorithm adjusts the actual pattern of arrays by modifying goal pattern in iteration. It can be applied to arbitrary array in which the individual elements have arbitrary radiation pattern. Some representative antenna arrays are sruthesized to show the validity of the methed, the calculated results are presented and discuased in detail.关键词：antenna arrays;pattern synthesis;numerical method;iterative algorithm2|361|2更新时间：2025-12-08
- 摘要：Based on the first airbome underwater targets detection test in China and Monte Carlo simulation, me key factors to the airberne oceanic lidar system, which include effective attenuation coefficient,atmosphere, speed of wind, turbidity layer, sloping of the undempter target, are studied. Some new approximation estimation formulation and curves which are suitabIe for engineering design are firstly derived. The abnormal phenomena in the test are explained. The problems needed to pay nrore attention to are also put forward.关键词：Airborne oceanic lidar;Effective attenuation coefficient;atmosphere;Turbidity2|212|1更新时间：2025-12-08
- 摘要：By the analysis of the shortcomings of the previous volume definitions of the wideband ambiguity function（WM）, a nedified WAF’s volume definition is first proposed. Secondly, in the wideband signal’s resolution analysis the timescale transform, freguency-seale transform and scale spectrum[1] are uesd and it is proved that the WBS’s range and velocity resolutions are determined by the WBS’s frequency spectrum and scale spectrum respectively. Fanally, sevaral kinds of signals are analysised by the method proposed in this paper, this provides an efficient analysing tool for the wideband signal processing.关键词：宽带模糊函数;距离和速度分辨率常数;时间-尺度变换;频率-尺度变换;尺度谱2|329|4更新时间：2025-12-08
- 摘要：Sparse-array Synthetic Impulse and A perture Radar （SIAR） can isotropicly radiate by etnploying multiple frequencies （synthetic pulse） and multiple antennas（synthetic antenna） without beam spanning. The detection ability to low RCS targets（especially to stealthy targets） is improved by use of VHF band and long-time coherent integration. An effective methed to reduct its range sidelobes with frequency-coding agility among these frequencies is presented. Also, the bandwidth of transmitting signals is raised by stepped-frequencies. The high range resolution is obtained by stepped-dfrequency synthesis and impulse synthesis of SIAR. A simple appoch for comensating the effect of target velocity on stepped frequencies is presented. Finally, the preliminary test is given.关键词：Sparse-array;synthetic impulse and aperture radar;Radar performance;Stepped-frequency synthesis;High-range-resolution2|254|2更新时间：2025-12-08
- 摘要：In this paper, the optimal estimators of the coefficients of a second-order bivariate polynomial for piecewise grayvalue distributions of image are derived by using the least quadrate multiplication,and the remaning components within eath patch can be attributed to white noise with zero meanvalue.Therefore, the quadratic model is set up, which is the best approacl to piecewise grayvauc distributions.In order to detect changes between consecutive frames, the statistical assumption test model which follows F-distribution with degrees of freedon（n+ 3, 2n-12） is detived based on the quadratic model,where n is the number of pixels in detection window. Because singe motion target can not be generally selected from the detected changes if there is noly F-test, the techniques of clustering analysis and filling holes are also designed, which can make the target loss and false alarm appronch to zerr. The experimental results made with the television-and infrared image sequences fully show the validity and compatibility of the technique route and key techniques proposed.关键词：image sequence;The quadratic model;Statistical assumption test;clustering analysis;Filling holes;False alarm2|131|3更新时间：2025-12-08
- 摘要：This paper considers the problem of tracking with multiple paseive sensors in the nonGaussian noise environrnent. The measurements possibly include random interferene and Glint noise. The methed of targt state estimation in this paper is a dynamic programming approach. Unlike the traditional method, we reduce the estimating problem to a multiple hypothesis-testing problem, and then use the dynamic programming algorithm to solve the problem of tracking with non-Gaussian noise.The simulation results show the superiority of new method.关键词：跟踪;动态规划;卡尔曼滤波;闪烁噪声2|302|4更新时间：2025-12-08
- 摘要：The electromagnetic reflecting characteristics of a plane wave incident on an infinite stratified Ω medium coated on metal are investigated by using Wave-Splitting Method in Frequency Domain,and some useful results are presented by examining the conditions which affect the reflecting characteristics.Finaly,we have designed theoretically anti-EM Ω reflection coating which can elfciently absord EM energy in a broad frequency range.关键词：Ωmedium;EM reflecting characteristics;Waves-Splitting Method in Frequency Domain2|45|0更新时间：2025-12-08
- 摘要：The problem of high resolution echoes time delay estimation for large time-bandwidth preduct LHM signals is investigated. A novel algorithm based on FFT for LFM signals enhancement used for preprocessing to raise the effective signal-to-noise ratio （SNR） is presented. In Order to overcome the redution difficulty in the case that echoes are highly correlated or coherent, ROOT-WSF algorithm is applied by use of inverse filtering in signal bandwidth. Finally, simulation results are included to demonstrate the improved perfornmnce achieved by the proposed method.关键词：linear frequency modulation;superresolution;signal enhancement;Root-WSF algorithm2|115|1更新时间：2025-12-08
- 摘要：Trilemna effect is an importarlt criteria for the self-convergence deflection system. The influence of the higher order Trilemma effect should be taken into account for the correction of the higher-order deflection aberrations. In this paper, when up to the seventh-order Trilemma contants are adjusted, the expression of the innuence of 2n-pole multipole field on n-th order Trilemma constant has been deduced and this innuence has been calculated.关键词：Picture tube;Trilemma effect;Deflection aberration2|17|1更新时间：2025-12-08
- 摘要：The quality factor of an open resonator with spherical circular mirrors and IE10 mode rectangular waveguide is calculated. The calculation is performed in the dipole approximation, but thc effect of the waveguide walls is taken into account in the magnetic polarizability tensor of the coupling hole. The calculations agree well with experimental data of the reference[2].关键词：Open resonator;coupling;quality factor2|78|1更新时间：2025-12-08
- 摘要：Simulation of wedge cathode vacuum microtriodes is presented. The characteristics of vacuum microelectronic devices are given by analyzing the results and calulating the relevant parameters.关键词：Vacuum microtriode;Wedge cathode;Simulation2|39|0更新时间：2025-12-08
- 摘要：In the electron beam scanning flat CRT, the electron beam usully is deflected several times. This paper analyses the deflection structure of FCRT. The electric field expression of the structure is given. From the variation equation, the Gauss trajection equation in the deflected optical axis coordinate is given. By comuter calculation, the factors affecting electron beam deflection is analysed.关键词：Electron-optics;electron beam;Electron-beam tube2|40|0更新时间：2025-12-08
- 摘要：The Conservation of Complex Power Technique is an effective methed in analyzng planar transmission lines and their discontinuity. In this paper, the Conservation of Complex Power Technique’s formulas are derived, and difterent ways are protw to sove som of thase problems. Detailed disoussion of the convergope of calculation results is given and the abruptness of calculation results is discovered.A simple methed to sove the problem is proposed within the limted computer resource.关键词：复功率守恒法;平面传输线;收敛性;突变性2|96|1更新时间：2025-12-08
- 摘要：This paper puts the random research strategy of simulated annealing methed into the Powell algorithm,calling them PSAM in brief. It can pretent optimizing course from trapping the local minimum and can get the global minimum, moreoer, a large number of iteration can be reduced. A typical algebraic equation with many local minimums is optimzed by PSAM. Its optimized course ooincides comletely with the idea of this paper and it presents a lot of advantages. At last, an ion source extraction system is also optimiZed by PSAM and satisfactory results have been got on the 586 microcomputer.关键词：Optimizing design;Simulated annealing method;Extraction system2|221|16更新时间：2025-12-08
- 摘要：This paper presets the explicit expression of gedesic equation on a paraboloids of revolution using differential geometry which avoids the complexity of geodesic ray tracing by numerical apprcach.The mutual coupling is derived using uniform geomtrical theory of Diffraction （UTD） and then is calculated by approximate apprcaches including Surface Radiation Pattern Methed （SRP） and Medified Surface Radified Pattern methed （MSRP）, which is important to the analyss of cohformal arrays.关键词：UTD;Conformal array on parabeloids of revolution;mutual coupling2|88|2更新时间：2025-12-08
- 摘要：Based on the multiscale idea,a fast algorithm to reconstruct the signal from its wavelet transform modulus maxima is built, in which the wavelet transforms of a step function are used as bases to reconstruct the wavelet transform of the sigul according to the medulus maxima on every scale, and then all of these components are used to reconstruct the signal by inverse wavelet transform. This methed is of explicit physical meaning and can be implemented conveniently. The methed of error medification is also given in this paper. Numerical results show that the fast reconstruction algorithm is effective for different types of signals.关键词：wavelet;Medulus maxima;Edges detection;signal reconstruction;multiscale analysis2|420|11更新时间：2025-12-08
- 摘要：A novel method named as VIM for microwave imaging of twodimensional dielectric cylinder in free space is presented. It is an iterative method based on volume equivalence principle and variation principle. The performance of it is examined throgh the reconstruction of many kinds of objects in the presence of random noise. Compared with the well known BIM, it inverts the unknown objects mor quickly and more accurately. It can rerenstruct the distribution of permttivity and conductivity simultanamsly. It is also shown that it can invert those complex objects such as multi-cylinder object, large object, high-contrast object. The behavior of this method in the case of incomplete scattering data is taken into account too. The effect of random noise and the capability of this method to invert unknowns using singe frequency scattering data are also investigated. We have also explained the reason why our method behaves better than the formr methods such as BIM and DBIM.关键词：Two-dimensional dielectric cylinder;microwave imaging;Variation principle;Inversion property2|89|1更新时间：2025-12-08
- 摘要：The TM0n multi-modal excitation of a coaxial line probe-to-circular waveguide is rigorously treated using the conservation of complex power technique. The overall scattering matrices of the coaxial line probe-circular wavguide are deduced, and computing results for the reflection coefficient of the coaxial line are then compared with the experimental results, both agree well. We also investigate the power distribution of various order modes excited in circular waveguide as a function of the probe length,and the analysis shows that the powper of the highest order mode excited in circular waxeguide is usually the largest.关键词：Coaxial line probe;circular waveguide;Multi-modal excitation2|368|2更新时间：2025-12-08
- 摘要：This paper solved the problem that are essential to the application of 2-D interpolation in analyzing the RCS of arbitrary shaped cavities. Such problems include selecting and changing of coordinate When setting up the inteedation function of the cavity’s inner surface, constructing the interpolation function and calculating the normal and curvature of the surface. This paper also discussed a general algorithm of tracking the rays in arbitrary cavities.关键词：Numerical methods;cavity structure;RCS;Ray methods2|83|1更新时间：2025-12-08
- 摘要：The method of differential-Thompson transformation is applied for the first time to the field of electromegnetic scattering by the authors. The complex objects and their comutational region are transformed by Thompson transformation to a regular region. By applving Fnite Difference. Time Domain method, the field distribution in regular region is solved conveniently. The results show that it is superior to the previous approaches.关键词：EM scattering;FDTD;Thompson transformation;Complex objects2|70|1更新时间：2025-12-08
- 摘要：A new EM scattering analysis methed for cavity structurcs, the Gaussian Ray Beam methed which synthesizes the advantages of both GO Rays and Complex Rays, is prooped in this paper.The plane wave simulation by using Gaussian Ray Beam and the reflection of Gaussian Ray Beam on curved interfaces are discussed. hane results of EM scattering analysis of cavity structures are given by using the Gaussian Ray Beam method.关键词：EM scattering;High frequency approximation;Cavity structure;numerical calculation2|72|2更新时间：2025-12-08
- 摘要：Trunk and Wilson proposed an algorithm for associating the DF （Direction-Finding） measurernents with radar tracks in [1],which is suited for the situations where both radar and DF traks are specified by different numbers of measurements. In 1he algorithm of [1], the decision thresholds were obtained by using Monte Carlo simulation techniques. The analytic expnaions of the deicsion thresholds in [1] are derive based on statistical theory, and the results are obtained by using numerical method.The computational results show that the analytical expressions are correct, and that it takes much less time to obtain the values of the thresholds by using the derived analytical expressions. Finally, simulation is made with satisfactory results.关键词：radar;DF;Association;Decision-thresholds3|51|1更新时间：2025-12-08
- 摘要：In this paper, the coupled-mode equations for chirowaveguides filled with homogenoous and isotropic chiral media arc derived,starting from Maxwell’s equations and the constitutional relations of chiral media. For the hybrid coupled modes existing in chirowaveguides, we get the general expressions of the coupled-mode equations, then under the condition of weak-coupling, we point out the idea of solving the coupledmode equations by the perturbation theorems, so a new theoretical aprroach has been formulated to analyze the discontinuily in chirowaveguides.关键词：Chirowaveguides;Coupled-mode equations;Eigen-function expansion theorem;Reference waveguide2|61|0更新时间：2025-12-08
- 摘要：The backscattering enhancement due to the surface-volume interaction in a vegetation canopy is investigated in this paper by directly adding up the scattering fields of scatterers and applying the Monte-Carlo simulation technique. The results indicate that stronger backscattering enhancement occurs when the canopy layer is thinner. The angular width of backscattering enhancement due to the surface-volume interaction is of the order of 1040 degrees.关键词：Random media;Electromagnetic scattering from vegetion;Backscattering enhancement;Monte-Carlo simulation2|152|2更新时间：2025-12-08
- 摘要：In this paper we use the moment method to analyze the characteristics of an isolated centered inclined slot on the broad face of a rectangular waveguide. Then we derive the scattering, matrix and the. equivalent impedance formulas. There are several triple integrals in the elements of admittance matrix. During numerical integration the triple integral is time consuming and divergent when the number of higher waveguide medes increases. Thus, we use an appropriate methed to reduce the triple integrals to double integrals, which are convergent, time saving and have better accuracy during numerical integration.The characteristic paramters obtained in this paper may be used to design a centered inclined slot array.关键词：裂缝;裂缝阵;波导裂缝;科研通信2|89|1更新时间：2025-12-08
- 摘要：In the measurrment and control system of aircraft, the quali1y of application software directly affects the reliability of the system. This paper will introduce the structure and charactcristics of the multi-process real-time software of the system, and will discuss the demand, methods and techuique of the software testing. An idea is proposed that a testing data dictionary is built, it has been proven practically that testing efficiency is greatly promoted.关键词：Multi-process;software test;Aircraft4|93|1更新时间：2025-12-08
- 摘要：Rewritting the independent loop’s equations of non-linear network given by field theory into network hole’s equations and solving them, a theoretical new formula for calculating the matrix element of independent loop by network hole’s determinant in non-linear or linear network was derived.Then the correctness of the formula was illustrated.关键词：Independent loop;Matrix element of independent loop;New formula2|74|2更新时间：2025-12-08
- 摘要：A novel 3-D time domain electromagnetic wav simulator for charactetistics of highspeed digital transmission lines in accordance with IC structures is described. It simulates a Gauss pulse to travel on arbitrary coplanar-type transmission line in the IC structures in 3-D space and time. It has been implemented on Convex 240 Vector/Parallel computer. The simulator is useful for the design of highspeed connection in IC and MCM.关键词：High-speed digital transmission lines;Full-wave simulation for electromagnetic field2|38|1更新时间：2025-12-08
- 摘要：In this paper, the application of the Measured Equation of Invariance in analysing transmission line with round outer conductor is intreduced. drie typical examples are numerically calculated.Good agreement between the results and those available in references is shown.关键词：Measured equation of invariance;transmission line2|47|1更新时间：2025-12-08
- 摘要：A new 3-D fusion tracking system for an anti-air missile homing system based on radar and imaging sensor is developed. The attitude measurements from the imaging sensor is used to improve the tracking performance. Data fusion techniques are employed to get least-mean-squares estimates. Computer simulation results indicate that the tracking system greatly reduces the tracking errors compared with trackers without attitude measurements, and achieves small miss distances even when the target performs a big maneuver.关键词：data fusion;Imaging sensor;Augmented porportional navigation;miss distance2|345|6更新时间：2025-12-08
- 摘要：The properties of disk-loaded coaxial resonator with slow wave mode are analyzed by the Borgnis’s potential function method. The characteristic equations and prerequisites to exist exclusively for the doninant mede among TM modes are obtained. Numerical evaluation is taken to show the dimension condensing effect of the slow wave structure. The results reveal that this kind of resonator is practical at frequencies down through micrvave band and RF band. Some working examples are also given.关键词：Disk-loaded;Coaxial resonator;Slow wave2|43|2更新时间：2025-12-08
- 摘要：This paper analyzes the statistic performance of the high resoution parameter estimation algorithm （MUSIC） in the presence of channel mismatch. The influence of Channel mismatch on spatial spectrum and the relationship between mismatch squaroerror and resolution ability are derived.The theory shows that the effect of channel mismatch on the performance of the algorithm is obvious.These formulas were validated by comuter simulation.关键词：Channel mismatch;Direction-of-arrival（DOA） estimate;error analysis2|227|10更新时间：2025-12-08
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