最新刊期
卷 ， 期 9 ， 1996
- 摘要：The difference equation with nine-point mesh of electromagnetic scattering from two-dimensional transversally anisotropic medium is derived in this paper.Themeasured equation of invariance and the difference equation are used to analyze electromagnetic scattering from transversally anisotropic medium cylinders with arbitrary section ,inhomogeneous,lossy and general electromagnetic parameters. Some results obtained for canonical anisotropic structures are given. The results show that this method is avail and have advantage in anlyzing and calculating this kind of problems.关键词：Anisotropic medium;electromagnetic scattering;Finite difference equation;Measured equation of invariance2|53|3更新时间：2025-12-08
- 摘要：Based on the consideration of different antenna height between transmitter and receiver and the height of super-refractive layer ,the XPD and CPA statistical distribution and its linear relation under the condition of equal probability are obtained ,which showing good agreements between simulations and experiments. Meanwhile , the effection to XPD and CPA distribution by the cross-polarization orientation patterns are also analysed.关键词：XPD;CPA;Computer simulation2|56|0更新时间：2025-12-08
- 摘要：The numerical method for derivation of diffraction coefficients of wedge characterized by fractal surfaces is described.We use the Finite-difference Time-domain （FDTD） method to compute the scattered field of an object possessing several scattering centers.The numerical diffraction coefficient of the scattering center under investigation is then obtained by solving simultaneous equations established via GTD consideration. The examples show the feasibility of the present method.关键词：FDTD method;GTD;fractal;Diffraction coefficient2|79|1更新时间：2025-12-08
- 摘要：Based on the scattering formulation of the physical optics,the distribution of the scattering energy determined by the variations of incident radar wave direction and main shape sizes is studied and the integration theory of shaping is put forward in the paper.It is concluded that the optimum sizes of two-dimensional wing shape should be satisfied with the zero point requirement of the sinc pattern and the sidelobe requirement of the same pattern. As the results of simulations, the curves of optimum size ranges in a two-dimensional model wing’s shaping are computed and drawn out.关键词：radar cross section;Integration of shaping;Flying object wing;Physical optics2|33|0更新时间：2025-12-08
- 摘要：The E,B representation of constitutive relations are given, the wave equation in moving medium and the equations which the longitudinal components of field quantities E,H satisfied are derived. For electromagnetic wave normally incident in an oncoming plasma half space,the wave reflection and transmission are solved,the dispersion relation and frequency relation of transmission wave are obtained,its frequency shift,wave cutoff and propagation reversion are discussed.For a pulse wave inczident,the reflected pulse compression and pulse amplification are calculated.关键词：Moving plasma;Constitutive relation;dispersion relation;Frequency shift;Wave cutoff;Pulse amplification.2|61|2更新时间：2025-12-08
- 摘要：The paper studies the near-field microwave imaging with the principles of CT and radar turntable imaging introduced. As extension of the back-projection,a concept of spherical back-projection（SBP）is proposed,and then a SBP algorithm is presented to reconstruct near-field microwave images of conducting objects.Numerical results show that the de4scribed method can be a cost-effecttive approach in near-field microwave imaging systems.关键词：microwave imaging;Near-flied imaging;Spherical back-projection2|97|7更新时间：2025-12-08
- 摘要：With the states of targets being projected into the measurement spaces of 2-D radar and IRST sensor,the JPDA algorithm is extended into the multisensor tracking system consisting of the two heterogeneous sensors for the appropriate data association to enhance the tracking performances based on fused data from multiple sensors.关键词：multitarget tracking;data fusion;data association2|423|51更新时间：2025-12-08
- 摘要：From the backscattering measurements of a two-point target consisting of two spheres,it is found out that the backward angular glint can be obtained by evaluating the derivative of the measured data of backscattering echo relative phase vs incident angle.A representative vector model of a N-point target consisting of N anisotropic scattering elements is proposed and investigated to reveal the inherent law implied by the experimental phenomenon. The theoretical results show that, under given conditions,there exists equivalence between the backward angular glint and the derivative of backscattering echo relative phase with respect to incident angle. This work not only clears up a misunderstanding on the concept of angular glint ,but also provides theoretical basis for obtaining angular glint by backscattering measurement in the case of no bistatic measurement capability.关键词：Echo phase;angular glint;radar target;electromagnetic scattering2|232|17更新时间：2025-12-08
- 摘要：The paper describes a kind of microwave probe survey system which can be used to measure plasma density variation of archeated tunnel.It also gives plasma shaping of arc-heated tunnel flow field. Experimental result of thermal ionization materials proves that the arc-heated tunnel is a good test means for seeking high ionization degree material of magneto-generation.关键词：microwave;Probe;Plasma diagnosis;Arc-heated tunnel2|213|7更新时间：2025-12-08
- 摘要：Effect of a wave modulated by symmetrical condensed node TLM mesh is researched for the analysis of electromagnetic wave using numerical method. A modified formulation is developed. The numerical results obtained with the formulation are compared with the analytical results.关键词：Electromagnetic field simulation;TLM method2|48|4更新时间：2025-12-08
- 摘要：A 3-D contour technique for curved surfaces in FDTD method is presented.It has been used in modeling the parabolid and Cassegrain antenna system.The near field distributions obtained are in good agreement with the values from other method and measured values.关键词：finite-difference time-domain method;Contour for curved surfaces;modeling;Cassegrain antenna system2|151|6更新时间：2025-12-08
- 摘要：The characteristics of the curvilinear dipole arrays with finite-size plate-reflectors are calculated by a hybrid method which combines the method of moment and the UTD,the dipole shapes and the array structures of some antennas are optimized for maximum gains.关键词：antenna;Reflector antenna;Curvilinear dipole;hybrid method;optimization2|77|2更新时间：2025-12-08
- 摘要：A new method for the measurement of complex permittivity of multilayered dielectric samples at millimeterwave and submillimeterwave bands by means of an electromagnetic open resonator is proposed. At Ka band an electromagnetic open resonator dielectric measurement system is designed and constructed using a specially machined open resonator set,and measurements on some multilayered dielectric samples are made,the results are in good agreement with the criterion values.关键词：Electromagnetic open resonator;Complex source-point theory;Multilayered dielectric sample;Dielectric measurement2|94|8更新时间：2025-12-08
- 摘要：In this paper,the unified theory on space-time adaptive signal processing for airborne radar has been proposed ,and a unified model for reduced dimension space-time adaptive processing has been developed. Based on this model,several typical local domain adaptive processors have been studied. Afterwords,a new concept,local domain clutter degrees of freedom , has been presented. It is very useful for designing the processor.Simulation results also have been given and made comparision in this paper.关键词：Space-time adaptive processing;airborne phased array radar;clutter suppression2|507|53更新时间：2025-12-08
- 摘要：A high-order mixed-edge rectangular element method is proposed for analysis of lossy dielectric guiding structures.The emphasis is laid on the investigation of the space construction of the high-mixed-order edge rectangular element and the explicit form of the shape function is given. The method provides a direct solution for propagetion constants wrthout the spurious solutions. The computationsof the propagation constants for the eigen modes in the rectanguar waveguide and slab loaded waveguide show that the accuracy of the high-order mixed-edge element approach is about one order higher than that of the lowest-order one. The calculations of the dispersion for the dominant mode in a lossy dielectric loaded waveguide verify the accuracy and efficiency of the present method.关键词：Lossy dielectric waveguide;High-order mixed-edge rectangular element2|36|3更新时间：2025-12-08
- 摘要：Motion compensation is the key of ISAR imaging,and is usually carried out in two steps. First,compensate the time delay of complex envelope ,which is a roughly alignment. Second,search for a reference point to precisely adjust the initial phase,which is usually referred to as autofocusing. The paper presents two improved autofocusing techniques called weighted multiple scatterer algorithrn （WMSA）and improved scatter centroid tracking （ISCT）. They are analyzed and compared with the dominant scatterer algorithm （DSA）. Finally ,the outdoor measured ISAR data of aircrafts are processed and the imaging results are compared with each other.关键词：ISAR;motion compensation;Autofocusing3|400|98更新时间：2025-12-08
- 摘要：The wide-band effect of the elliptical resonant iris in rectangular waveguide is treated as the variational stability of the geometry of iris,so the wide-band design method of this kind of iris is presented.It is also shown that the wide-band effect is the result of the shift of resonant frequency and the change of the slope of conductance-frequency curve.关键词：resonant iris;variational stability;wide-band design2|104|1更新时间：2025-12-08
- 摘要：In this paper,Equivalent Small Parameter Method（an improved perturbation technique）[6]is utilized to analyze the PWM converters containing multi working stages, such as cosverters in discontinuous conduction mode （DCM）or with multi switches. The solutions are all the symbolic expressions.关键词：Switching power converters;Discontinuous conduction mode;Multi working stages;symbolic analysis2|212|36更新时间：2025-12-08
- 摘要：The multiple access protocol of the third generation microcelular wireless communication systems is researched in this paper.The performance of priority packet reservation multiple access（Pprma）joint high and low priority voice terminals is discussed. Adaptive packet reservation multiple access （Aprma）is proposed. System simulation is carried out and performance of Aprma is evaluated.关键词：Packet Reservation Multiple Access;priority;adaptability2|36|1更新时间：2025-12-08
- 摘要：This paper introduces a signal sorting method based on a self-organized probabilistic neural network （PNN） and mainly discusses its application for sorting radar signai. A synthetical sorting method for special radar signal is discribed.The feasibility of this method is verified after lots of emulated experiments.关键词：neural network;signal sorting;radar2|363|34更新时间：2025-12-08
- 摘要：An iterative algorithm is proposed in this paper. To reconstruct the complex pernuttivity of a 2-D inhomogeneous lossy dielectric object from the measured scattered fields ,the object is illuminated successively by TM plane waves of different angles of incidence,and the scattered fileds are measured,for example,at a measurement line.By using the method of moment ,the integral equation can be discretized into matrix form.Starting from Born approximation,the coupled matrix equations are solved iteratively.In general ,inverse scattering problems are mostly illconditioned. In order to overcome the ill-conditioness ,we apply the conjugate gradient method.The computer simulations show the feasibility of the proposed reconstruction scheme.关键词：inverse scattering;reconstruction;CGM;Mom;iterative method2|71|7更新时间：2025-12-08
- 摘要：Rectangular microstrip antennas with deilectric cover have been investigated theoretically and experimentally.A full-wave analysis modelis developed to analyze microstrip antennas with dielectric cover. Formulas for the input impedance and radiation pattern of antenna are given.Practical microstrip antenna problems,such as the effect of superstratum on resonant frequency and input impedance are discussed.The numerical results have been verified by the experimental results.关键词：Microstrip antennas;Dielectric cover;Full-wave analysis;Antenna experiment2|223|5更新时间：2025-12-08
- 摘要：The estimation of instantaneous frequency using the peak of the Wigner-Ville distribution（WVD） is unbiased for sinusoid of constant amplrtude and linear modulated frequency. In this paper we analyze the effects of the time-varying amplitude of a monocomponent signal on the WVD peak estimator,and find that if the modulated signal satisfies the Bedrosian theorem,the time-varying amplitude does not affect the estimation of instantaneous frequency.And the unbiased condition of the peak estimator is loosened.关键词：Instantaneous frequency estimation;Wigner-Ville distribution;signal processing2|247|15更新时间：2025-12-08
- 摘要：A novel unit for phased array antennas,of which the current can be detected,is presented. A small-loop antenna is introduced on using it for a prober and its effection is discussed to the characteristics of the unit and array. On the tested results,the conclusion can be obtained that the performance of new model unit is almost the same as that of the unit which is without the detecting antenna.关键词：Phased-array antenna;Array unit;Detecting antenna;Unit performance2|199|3更新时间：2025-12-08
- 摘要：We report a nhole-induced subcritical period-doubling bifurcationi and the corresponding type Ⅱ intermittency that was observed numerically in a circle map describing an electronic relaxation oscillator. Compared with the conventional subcritical period-doubing bifurcation ,its characteristic is that the pair of the unstable periodic orbits ,which collide with the stable periodic orbit ,originate from two special discontinuities of the map.关键词：Relaxation oscillation;discontinuity;Intermittency2|33|2更新时间：2025-12-08
- 摘要：A new method describing the relation of the fields on two closed curve surfaces by matrix is introduced. By utilizing this method ,an object functional on phase inverse problem which has been focused in recent years in near and far field transformation is created. Comparing with other functionals,this functional belongs in real space rather than complex space. Its form is very simple and it is easy to calculate the gradient of the functional.The data processing is decreased greatly. The conjugate gradient method （CGM） is taken to mininize the object functional.The numerical results show that the phase of a closed curve surface can be retrieved completely when the initial phase value points are located in the vicinity of the solution. At last,the existence of multipolar value in phase inverse problem is discussed by functional theory.关键词：Near and far field transformation;phase retrieval;Far field reconstruction2|127|0更新时间：2025-12-08
- 摘要：An adaptive pulse compression filter apphed to signal processing of subsurface radar is introduced ,and LMS algorithm is improved. The results of computer simulation show that the filter has good tracing compression properties for oblect echo and the vertical resolution of subsurface radar is improved obviously.关键词：Subsurface radar;adaptive filter;pulse compression2|161|6更新时间：2025-12-08
- 摘要：The theoretical analysis of fin line with anisotropic substrate is researched rigorously for the first time.In the spectral domain,we determined the general dependences of wave vector, polarization properties and scalar wave eqaations on the major axis in the birefringent plates,and carried out the field solutions and G martices of the fin line with Z-cut and Y-cut crystal substrates for examples.关键词：Fin line;Anisotropy;Spectral domain;Wave vector;Polarization2|45|0更新时间：2025-12-08
- 摘要：In this paper we analyse the metal-clad antiferromagnetic slab frequency properties. The comparision of propagating properties of antiferromagnetic slab with those of dielectric slab are discussed in detail.关键词：Antiferromagnet;Salb2|27|1更新时间：2025-12-08
- 摘要：天津大学电子工程系Ｄｅｐｔ．ｏｆＥｌｅｃｔｒｏｎｉｃＥｎｇｉｎｅｅｒｉｎｇＴｉａｎｊｉｎＵｎｉｖｅｒｓｉｔｙ天津大学电子工程系的前身天津大学电信工程系成立于１９５２年，１９５５年天津大学电信工程系迁往北京，创建北京邮电学院，１９６０年５月天津大学恢复...2|22|0更新时间：2025-12-08
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