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A surface-wave-based endfire antenna with an enhanced impedance bandwidth is presented in this paper. The antenna consists of a surface-wave guide (SWG) and five strips printed on the SWG. The endfire radiation benefits from the surface-wave diffraction of the SWG which is investigated with the Snell's law, effective surface impedance and eigenvalue analysis. A prototype is fabricated and measured, and the measured results indicate that the antenna has two resonances and its bandwidth is enhanced up to 16.1% (4.0-4.73 GHz). The proposed endfire antenna also exhibits high gain, good gain flatness, low cross-polarization level and low profile. [ABSTRACT FROM AUTHOR]

Here, new kinds of surface waves on nanostructured metamaterial (MM), crossing the light line with a substantial portion at lower frequencies lying above the free space light line, are considered. We present the numerical study of dispersion features of hyperbolic MMs for various cases, and the tunability of hyperbolic MMs based on grapheme-dielectirc multilayers and transparent conducting oxide-dielectric multilayers have been demonstrated. Similar to grapheme-dielectric MM, the propagation of the new surface waves on nanostructured MM presented in this manuscript is sensitive and can be controlled by the parameters of the materials employed in nanostructures. Remarkably, the parameters of the materials employed in nanostructures dramatically influence the propagation of such surface waves. Additionally, the Ferrell-Berreman modes are detected under certain conditions, providing a fertile ground for device fabrications. [ABSTRACT FROM AUTHOR]

In this paper, reflected, transmitted, and loss powers of p-polarized electromagnetic waves through a lossless dielectric slab embedded between two double negative media are studied. Lorentz and Drude medium models are both considered for the dispersion of the double negative materials in the surroundings. The dependences of reflected, transmitted, and loss powers on the incidence angle, incident wave frequency, and dielectric slab thickness are investigated. The results reveal many interesting features. The damping frequency has a slight effect on reflected, transmitted, and loss powers in most waveguide configurations considered. Moreover, the loss power is small and can be significantly reduced by considering Drude dispersion model and careful choosing of the proposed structure parameters. [ABSTRACT FROM AUTHOR]

In this paper, the interaction between terahertz wave and a non-uniform magnetized plasma slab is investigated. The electric field distribution in non-uniform plasma is presented and used to calculate the attenuation of the electromagnetic wave through plasma. Several types of electron density profiles are proposed and discussed. Effects of different plasma parameters (electron density, collision frequency, plasma thickness) and magnetic field amplitudes on THz wave attenuation characteristic are investigated. The transmission ratios at several typical THz signal frequencies in both unmagnetized and magnetized plasma are presented as well. These simulation results are meaningful for the flight communication. [ABSTRACT FROM AUTHOR]

This paper presents a digitally supported signal injection technique for the intermodulation distortion terms (IMDs) resulting from the non-linearity of Traveling-wave tube amplifiers. It is shown that the state-of-the art analog techniques have inherent limitation due to the inaccuracy of analog components. The proposed technique provides more accurate cancellation of third-order IMD as compared to its analog counterpart. Moreover, it is shown that the presented technique can be easily extended to compensate for higher order IMDs simultaneously. [ABSTRACT FROM PUBLISHER]

My efforts to “bridge the gap” span a period of nearly 40 years and consist of over 100 courses on microwave tubes presented to well over 2000 scientists, engineers, and technicians. I developed the first five-day course for the US Navy. After several more courses, I wrote Microwave Tubes. In 1988, I developed the equivalent of a one-semester course on traveling wave tubes for the Navy and presented it several times each at Teledyne, Litton, Varian, and Hughes. In 1994, I wrote Principles of Traveling Wave Tubes, which was translated and published in Russia. I continued expanding and refining the courses and, in 2011, I wrote Klystrons, Traveling Wave Tubes, Magnetrons, Crossed-Field Amplifiers, and Gyrotrons, which was translated and published in China. Most recently, my courses have been attended by scientists and engineers from China, Sweden, Turkey, the United Kingdom, and Germany as well as the United States. [ABSTRACT FROM PUBLISHER]

In this paper, a new approach for electromagnetic modeling of the diffraction of finite multi-dielectric thickness in metallic wave-guides is presented. The proposed model, based on the method of moments combined to the generalized equivalent circuit, can concern several applications such as the investigation of vegetation leaves properties. Hence, in this work, we are interested in studying a corn leaf which is assumed as a superposition of rectangular dielectric slabs. We develop an electromagnetic analysis of a rectangular wave-guide loaded with a dielectric model that is composed of a leaf plant with a finite thickness. Interest has been focused on the influence of the wave diffraction according to the geometrical intern of the corn leaves. In this paper, we are particularly interested in studying these parameters against the dielectrics widths and the distances separating them. To validate this work, the obtained results are compared with those previously measured and published. A good agreement with literature is shown. [ABSTRACT FROM PUBLISHER]

A novel planar travelling-wave ring array with polarisation agility is introduced. The array is built by applying the sequential rotation technique with the complementary strip-slot element. This element is a conventional microstrip series-fed slot with the special feature of very broad impedance bandwidth thanks to the strip superimposed into it on the microstrip layer. The feeding of the array elements and the required phase shift between them are provided by a ring-shaped microstrip line, which is terminated in two ports. Vertical linear polarisation, horizontal linear polarisation, right-handed circular polarisation and left-handed circular polarisation can be generated with this very simple planar structure, just by controlling the phase and amplitude of the excitation at the two ports. Moreover, thanks to the wide impedance bandwidth of the element, multiband behaviour is achievable. A design example that operates at three different bands (centred around 6, 9 and 12 GHz) is analysed, which presents very good matching ( dB), polarisation purity and broadside radiation pattern. [ABSTRACT FROM AUTHOR]

This paper presents a discrete model for rotor shaft and stator winding of an electrical machine. Multi-conductor transmission line theory is used for modeling connecting cable, stator winding, and rotor shaft. The conductors used in a stator winding are connected similarly to a multi-conductor transmission line using electrical and magnetic coupling effects. Modal theory is applied to the wave equations of the stator winding to obtain a discrete model for electrical machines winding. The voltage distribution in the stator winding, rotor shaft, and bearings were obtained by numerical simulation under symmetrical conditions and compared with published results for time-domain method. The consequences of a static eccentricity fault on shaft voltage were determined and evaluated using a symmetrical machine. [ABSTRACT FROM AUTHOR]

We propose the design of a dual-anode electron gun, so named due to the presence of an additional electrode, namely, the control anode in the vicinity of the cathode in addition to the ion-barrier anode and the ground anode. We found the potential of the control anode to play an important role in enhancing the life of a space traveling-wave tube. By a telemetric command, one could control the control anode potential with a view to enhancing the cathode current that would otherwise deteriorate with the progress of time. Further, due care was taken in the thermal design by providing a heat shielding of the cathode of the proposed dual-anode gun to ensure that the cathode, which is operated at a lower temperature for a longer cathode life, does not further suffer a decrease in temperatures due to heat dissipation. Furthermore, to compensate for the deterioration of the cathode current with the progress of time, we propose the application of a nominal change in the control anode potential by a telemetric command. The electrostatic and thermal simulations of the proposed dual-anode gun were carried out by the commercial simulation codes EGUN and ANSYS, respectively. The paper presents the effect of heat shield thickness and material property on the cathode temperature as well as the effect of the structural deformation caused by the axial and radial expansion of the cathode on electron beam optics, a demountable dual-anode gun was set up for validating the cathode temperature against simulation. [ABSTRACT FROM PUBLISHER]

A multi-stage traveling-wave waveguide-based spatial power divider/combiner using waveguide-to-microstrip (Wg-Ms) probe-pair coupling structure is proposed and applied to the design of a broadband power-combined amplifier module at Ka-band. An eight-way passive back-to-back power divider-combiner with four-stage Wg-Ms probe-pair transitions has been designed, fabricated, and tested. The measured overall insertion loss is less than 1.5 dB from 28 to 40 GHz, which demonstrates the low-loss performance of the proposed multi-way dividing/combining structure. Based on the passive power divider/combiner, an eight-device power-combined amplifier has been implemented with eight broadband medium power amplifier chips. The measured small-signal gain of the amplifier is more than 18 dB and the output power at 1-dB gain compression (P-1 dB) is higher than 30 dBm in the frequency band of 28–40 GHz. Power combining efficiency is within the range of 76–88%. Furthermore, the performance degradation of the power-combined amplifier due to device failure is also analyzed and tested. The experimental result indicates the reliability of this type of power-combined amplifier. [ABSTRACT FROM PUBLISHER]

We investigated the dependence of the input impedance and radiation characteristics on the connection angle between the DC bias stripline and the center dipole of a terahertz coplanar stripline dipole antenna in a semi-infinite substrate. Three connection angles, namely 0° (typical horizontal connection), 45° (diagonal connection), and 90° (vertical connection), were examined and an overall performance comparison was provided. The antenna with a sufficiently long bias stripline exhibited a traveling-wave behavior with stable impedance variation, regardless of the connection angle between the DC bias stripline and the center dipole. The antenna with diagonal and vertical bias connections performed much better than the typical H-shaped electrode with a horizontal bias connection in terms of radiation characteristics exhibiting flat gain and low frequency cut-off of the radiation efficiency. In addition, the antenna with a diagonal bias connection exhibited a better radiation pattern and more efficient use of a given substrate area than that with a vertical bias connection. The result indicates that in terms of the overall aspect of the terahertz stripline dipole antenna designs on a high-dielectric-constant substrate, the antenna with a diagonal bias connection is the best configuration. [ABSTRACT FROM AUTHOR]

By means of the coordinate transformation method, displacement cloaks, which can transform an object into a much bigger illusion elsewhere, were presented and verified. The illusion possesses much stronger scatterings and is at an oblique distance from the object. In this way, detections or attacks are diverted to the non-existent illusion, rather than the true object. Full wave simulations on the basis of the finite element method verifies the designed displacement cloaks. [ABSTRACT FROM AUTHOR]

Based on compressing coordinate transformation (CCT) that transforms a region into a smaller region, a rigorous method for designing a cloak with controllable open window is proposed. The open cloak consists of a portion of an ideal closed cloak and an independent system whose position and parameters can be controlled. The system could be circular or diamond-shaped with coordinate transformation in radius direction and one axis of Cartesian coordinates, respectively. This cloak is able to externally hide an arbitrary-shaped object with arbitrary material property including PEC, and the object is open to the outside space. Full-wave simulations validate this rigorous cloaking concept. [ABSTRACT FROM AUTHOR]

In this pater, a novel substrate-integrated waveguide (SIW) square cavity dual-mode filter is proposed. By using an orthogonal input and output feed-line and two tuning metal vias for disturbing two degenerate modes, a transmission zero is derived. A SIW dual-mode filter with the center frequency of 14.7 GHz was fabricated and measured, in which fractional bandwidth is 3.8%. The measured results show good agreement with the simulated ones and validate the structures of the dual-mode filters. [ABSTRACT FROM AUTHOR]

A novel fractal triangular monopole antenna with truncated and notched ground for the ultra-wideband (UWB) application is presented and studied in this paper. The proposed antenna is designed based on the fractal theory. By inserting three small triangles and three thin slots central symmetrily in the radiation patch, smaller antenna size and more resonant frequencies in the required frequency range are obtained. The antenna has been simulated, fabricated and measured. It is shown that high performance of the designed-antenna is obtained and the Voltage Standing Wave Ratio (VSWR) requirement of less than 2.0 in the frequency band from 2.6 GHz to 14.26 GHz is well satisfied. [ABSTRACT FROM AUTHOR]

In this paper, exponential finite-difference time-domain (E-FDTD) method is applied for the calculation of plasma dispersive medium. The high efficiency and accuracy of this method is verified by calculating the reflection and transmission of the plane electromagnetic wave impinging on a plasma dispersive medium slab. The result of E-FDTD method is compared with exact result, auxiliary differential equation (ADE) and frequency-domain finite-difference time-domain ((FD)2TD) method. It proved the E-FDTD method has high efficiency and accuracy in plasma dispersive medium computing. [ABSTRACT FROM AUTHOR]

The multi-objective optimization NSGA-II approach has been proved that, in most of times, it has much better spread of solutions and better convergence near the true Pareto-optimal than mostly Pareto-optimal method. But there are also disadvantages to restrict the spread uniformity in some problems. This paper overcomes these disadvantages to get three modifications such as the cumulate dummy fitness strategy, disconnected filling strategy, and throwing off strategy by selection limit. The comparison with simple NSGA-II shows that the great efficiency is achieved by using the improved NSGA-II in most of times, because the improved approach can spread value space and give a more reasonable rule for preponderant individuals. [ABSTRACT FROM AUTHOR]

A resolution enhancement method for estimating the direction-of-arrival (DOA) of signals for coherent signals impinge on a uniform circular array is proposed. It increases the aperture size by virtually expanding the sensor spacing of original antenna array which is constructed by the steering matrix of the virtual array using the proper transformation matrix. Superior resolution is achieved with this method in comparison with the standard Deterministic Maximum Likelihood algorithm for coherent signals impinge on a uniform circular array. [ABSTRACT FROM AUTHOR]

The article presents a list of books and reports related to the topic of electromagnetic waves. The reports and books include "Progress in Electromagnetics Research," by J.A. Kong, "Metamaterials Exhibiting Left-Handed Properties and Negative Refraction," by T.M. Grzegorczyk, "Electromagnetic Applications of Photonic Band Gap Materials and Structures," by A. Priou and T. Itoh "Polarimetric Microwave Remote Sensing of Wind-Driven Ocean Environment," by Y. Zhang and T.M. Grzegorczyk and "Geometric Methods for Computational Electromagnetics," by F.L. Texeira.

Plane electromagnetic wave propagating in perfect electromagnetic conductor (PEMC) is considered. Its wave number has no connection with the frequency. An interface is introduced between an ordinary isotropic medium and PEMC. The wave in PEMC is matched to plane electromagnetic wave incident normally on the interface from the ordinary medium and reflected from it. Then the plane-parallel slab made of PEMC is considered and a plane wave is found in it. [ABSTRACT FROM AUTHOR]

An anisotropic mushroom-like electromagnetic bandgap (EBG) structure is studied. Different to the conventional EBG structures with square unit cell, the presented EBG structures are with anisotropic periodicity. The periodic spacing or the metal patch length is different along the two periodic directions. So the reflection phase and the frequency bandgap will show distinct characteristics compared to the conventional EBG structures. These two features of the anisotropic EBG structures have been calculated numerically using FDTD method. The results show that the frequency of in-phase reflection is dependent on the polarization of incident plane wave, and the frequency bandgap along the two orthogonal directions could be designed to be similar or even overlapped. [ABSTRACT FROM AUTHOR]

The article presents a list of books and reports related to electromagnetic waves. The information resources include "Scattering of Electromagnetic Waves: Advanced Topics," Vol. III, by L. Tsang and J. A. Kong, "Electromagnetic Wave theory," by J. A. Kong, "Progress in Electromagnetics Research," by J. A. Kong, "Polarimetric Microwave Remote Sensing of Wind-Driven Ocean Environment," by Y. Zhang and T. M. Grzegorczyk, and "Electromagnetic Theory and Network Methods," by M. Tateiba and L. Tsang.

In this paper, we study rain attenuation at Ka-band in northern Taiwan from long-term experimental measurements using a Ka-band (28.35 GHz) CW system at vertical polarization, optical rain gauge, and 2D optical distrometer that measures the rain drop size distribution (DSD). The DSD were measured and analyzed for different seasons under various rain rates. The variability of DSD in both space and time was clearly shown even in the not so large area of Northern Taiwan. It follows that a relationship between rain rate and DSD was established. From statistical regress, it was also found that the DSD follows the Gamma distribution best in most cases. Making use of the Gamma-distribution for DSD along with a two-year set of continuously measured data (2002–2003), a semi-empirical rain attenuation model was then developed. To validate the model, we compared it with the measured data. The results show that the proposed model matched very well with in-situ measurement from a two-year data set. [ABSTRACT FROM AUTHOR]

A simple and systematic derivation of strongly well-posed perfectly matched layer (PML) in cylindrical and spherical coordinates is presented. The unsplit-field PML formulations are expressed in terms of the complex coordinate stretching approach which was originally proposed for split-field PML. The well-posed PML formulations include the symmetric hyperbolic system besides some lower order terms which do not affect the well-posedness of the system. Numerical simulations validate the accuracy and efficiency of the unsplit-field PML. [ABSTRACT FROM AUTHOR]

This paper presents a new set of formulas to compute the field distribution near an electrically large conductor modeled by non-uniforrn rational B-spline (NURBS) surfaces using physical optics (PO) method. Stationary phase method is applied to calculate the PO integral on the rational Bezier Surface. Results obtained by these formulas and by traditional PO method using triangle-modeling technique agree well, which show the accuracy and efficiency of this method. [ABSTRACT FROM AUTHOR]

The article lists books and reports related to electromagnetic waves, including "Scattering of Electromagnetic Waves (Vol. Ill): Advanced Topics," by L. Tsang and J. A. Kong, "Progress in Electromagnetics Research," by J. A. Kong, "Electromagnetic Scattering by Rough Surfaces and Random Media," by M. Tateiba and L. Tsang.

Simultaneous measurements of Ku-band attenuation and rain-rate give A0.01 and R0.01 9.7 dB and 54 mm/hr respectively, Unlike the monotonous variation predicted by the ITU-R model, breakpoints wore observed in both the rain-rate and Ku-band attenuation exceedances. Similar observations were reported from other stations in the tropics. The accumulation time factor measured at the breakpoints remained almost a constant in these stations. Using this it is predicted that for stations with high elevation angle receivers, at breakpoint rain-rates, one rain-cell intercepts the propagation path of the signal. It is estimated that, in the tropics, the diameter of a rain-cell is ∼1.5 km when the rain-rate begin to saturate. [ABSTRACT FROM AUTHOR]

A novel method is presented for scattering by cylinders uniformly moving in free-space. The method is based on the application of differential-operators to the rest-state scattered waves. This method is applicable to any solution of the Helmholtz wave equation expressed in terms of a separable coordinate-system, in particular it is demonstrated here for circular and elliptical wave-functions. The analysis applies to arbitrary cylindrical geometries and is based on plane-wave representations which facilitate simple and compact formulas. [ABSTRACT FROM AUTHOR]

Analytic solution to the problem of scattering of a plane electromagnetic wave by a dielectric coated confocal conducting elliptic cylinder loading a semi-elliptic channel is investigated. The incident, scattered and transmitted fields in every region are expressed in terms of Mathieu functions. Applying the boundary conditions at various interfaces along with the partial orthogonality properties of angular Mathieu functions, the unknown scattered and transmitted field coefficients are obtained and written in matrix form. The presented numerical results show that the presence of a dielectric coated conducting elliptic cylinder changes significantly the echo patterns width of the elliptic channel. [ABSTRACT FROM AUTHOR]

The modes of electromagnetic wave propagation in a circular tunnel with lossy walls such as concrete are obtained by applying the impedance boundary conditions on the wave solution inside the tunnel. The attenuation coefficients of the lowest order modes are calculated as a function of frequency. The results are found to agree well with the published results using other methods. An equation is proposed to represent the attenuation as a function of frequency and tunnel radius. This work can be easily extended to the case of rectangular tunnel. [ABSTRACT FROM AUTHOR]

A sensitive microwave detector based on carrier wave zero-balance technique for abstracting human microwave cardio-graph (MCC) is established. More than eight hundred MCGs under various conditions are collected with this apparatus. It is shown that all the MCGs present a strong dependence on those conditions, such as the position of the receiving antenna, persons under testing, and their postures. Careful analyses of the experimental results show that the operation mechanism of this type of detector should be attributed to both the Amplitude Modulation (AM) and Phase Modulation (PM) of the heartbeat to the scattering field, instead of well-known Doppler effect, even though almost a similar apparatus is used. [ABSTRACT FROM AUTHOR]

We present a modified version of the curvilinear coordinate method (C.C.M.) for simulating electromagnetic waves scattering by rough surfaces. Numerically the field is obtained from the solution of an eigenvalue problem in Fourier Space. Unfortunately, it appears that the field suffers from parasitic oscillations related to finite spectral resolution. These oscillations are successfully removed by coupling the C.C.M. with the Stratton­Chu formulas. [ABSTRACT FROM AUTHOR]

This paper present a numerical method for solving the controlled Duffing oscillator. The method can be extended to nonlinear calculus of variations and optimal control problems. The method is based upon interpolating scaling functions. The differential and integral expressions which arise in the system dynamics, the performance index and the boundary conditions are converted into some algebraic equations which can be solved for the unknown coefficients. Illustrative examples are included to demonstrate the validity and applicability of the technique. [ABSTRACT FROM AUTHOR]

The scattering of a plane electromagnetic wave from a dielectric or metallic sphere external to another one, also dielectric or metallic, of electrically small radius, is examined. The method of separation of variables is used, in conjunction with translational addition theorems for spherical vector wave functions. Analytical expressions are obtained for the scattered field and the various scattering cross-sections. Numerical results are given for dielectric and metallic spheres and for various values of the parameters. [ABSTRACT FROM AUTHOR]

As a target is immersed in the rain medium, its detection and identification become difficult due to that scattering wave from the target is mixed with echoes from raindrops. These clutters induce a strong effect in millimeter wave band and the signal-versus-clutter ratio (SCR) is therefore deteriorated at the receiving terminal. In this paper, Lagrange multiplier method combined with iteration method is proposed to calculate the optimal polarization characteristics both for the transmitting and receiving antennas of radar to improve SCR for the coated target in rain medium. As an application for the method, polarization status of antennas with best SCR both for co-polarization channel and cross-polarization channel are obtained utilizing the rain statistic data of Xi'an China. This hybrid method for calculating polarization parameters has applications in self-adaptive polarization matching of antenna in the electrical system. [ABSTRACT FROM AUTHOR]

A new non-uniform structure is presented to reduce the crosstalk and maximize the delivered power to the main load in VLSI circuits. This interconnect is designed to meet the matching requirements in the load (user) and the source (die). In this structure some grounded non-uniform lines are added in the empty space between signal traces and so no additional space is required. This structure is compared with the conventional interconnects. The method of the solution is based on steplines approximation of non-uniform lines and modal decomposition method for the coupled lines. [ABSTRACT FROM AUTHOR]

The cutoff characteristic equation of the modes in circular waveguide is derived in this paper. The TM01 mode inversion has been investigated. Two kinds of technique of dielectric loading have been discussed. When the dielectric tube is filled in the waveguide next to the waveguide wall, there is no window of TM01 mode inversion observed in the cutoff characteristics. Contrarily, when the dielectric is filled centrally in the circular waveguide, there always exists one "window" within which the TM01 mode can propagate in the waveguide in the sense of single mode. [ABSTRACT FROM AUTHOR]

In this article we present a simple and practical analytical approach based on scalar wave approximation to estimate the modal dispersion characteristics and cutoff condition of an optical waveguide having an arbitrary and uniform core cross-section. This structure represents the core of a circular waveguide which is compressed at both the ends of diameter. We choose the new and appropriate orthogonal coordinates for the proposed waveguide structure and impose the boundary conditions under the weak guidance approximation to get the modal eigen value equation. Using this equation we achieve numerical results in the form of dispersion curves and cutoff frequencies. Further representing the normalised frequency parameter a V and normalised propagation constant as b the dependence of &fracd(VV)dV; on V has been obtained and shown graphically. A brief comparison of the proposed waveguide and the circular waveguide has also been made in respect of the number of sustained modes and waveguide dispersion [ABSTRACT FROM AUTHOR]

Open-ended coaxial probes are commonly employed for the dielectric characterization of materials due to several well-known advantages. This measurement technique, consisting in measuring a relfection coefficient, Γ involves an inversion procedure: given the measured Γ the unkown complex permittivity, εM of the material under test (MUT) is computed by means of an electromagnetic (EM) model of the probe contacting the MUT. For this purpose, a mixed analytical/empirical/full-wave optimization to permittivity measurement is here proposed. The experimental results obtained by a 3D full-wave mode of the finite-flanged coaxial probe in the 2–3 GHz range, are discussed by comparing with those computed according to an analytical EM model involving an infinite flange [1]. Thee effect of the flange size on the permittivity measurement precision is also analyzed. [ABSTRACT FROM AUTHOR]

The distortion of pulse waves propagating in some shielded composite ferrite microstrip transmission lines (FMTLs) is studied in this paper. The mathematical treatment is based on the Galerkin’s method in the spectral domain and the fast Fourier transformation (FFT). The hybrid effects of the biasing magnetic dc field intensity and its orientation on the pulse wave distortion are examined and compared. It is shown that the pulse distortion can be effectively reduced by changing the biasing field intensity or orientation. [ABSTRACT FROM AUTHOR]

A model for a chiral material in which both the permittivity and permeability are equal to zero is discussed. Such a material is referred by us as a g on what level of spatial aggregation is employed. This note combines a multivariate extension of earlier bivariate, ordinal analyses (Thompson, 1972, 1975) conducted at the world level with a comparative examination of Latin American and sub-Saharan African data. The outcome indicates that regional aggregations do provide stronger support for regime vulnerability hypotheses than do world aggregations but that the amount of variance accounted for by the indirect variables encompassed by regime vulnerability arguments continues to leave much to be explained. [ABSTRACT FROM AUTHOR]

Some properties of Green's functions of waves at boundaries are presented in this paper. Of particular interest is their behaviour like Dirac delta distributions whose domain is the manifold of the boundary under consideration. We have obtained relations involving dyadic Green's functions for electromagnetic wave scattering problems with PEC, PMC and penetrable boundaries. Both isotropic and anisotropic homogeneous media are considered. Situations with multiple bodies with disjoint smooth boundaries are also part of our study. Some similar results for acoustic waves are given without proofs. [ABSTRACT FROM AUTHOR]

Focuses on the full wave analysis of the integrated planar structures in the spectral domain. Use of the microstrip and microslot integrated structures in microwave and millimeter wave applications; Characteristics of the integrated antennas; Diffraction of the surface waves.

Presents a study which analyzed the full wave of rounded ends iris and its applications in coupling. Discontinuity between rectangular iris and rectangular waveguide; Configuration and analysis; Analysis of numerical results.

Focuses on a study which analyzed the diffraction of focus wave modes by circular and rectangular plane apertures using the Kirchhoff-Huyghens diffraction integral. Extension of Kirchhoff-Huyghens diffraction integral to arbitrary time-dependent fields; Approximation of the Kirchhoff-Huyghens integral.

Deals with a study which proposed a model for Doppler effects involving translatory and moving surfaces on which certain boundary or source conditions are prescribed. Discussion on integral representations and wave fields; Limitations of spatiotemporal analysis; Origin of consistent and inconsistent approximations.

A new formation of a time domain incremental theory is introduced. This approach is applied to the scattering of a pulsed plane wave incident on a circular disk. It is shown that the scattered field is free from singularities at caustics and exhibits a notable wave structure outside Keller's cone. [ABSTRACT FROM AUTHOR]

An efficient, static fast multipole method (FMM) based algorithm is presented in this paper for the evaluation of the parasitic capacitance of 3-D microstrip signal lines embeddedin stratified dielectric media. The effect of dielectric interfaces on the capacitance matrix is included in the stage of FMM when outgoing multipole expansions are used to form local multipole expansions. The algorithm retains O(N) computational and memory complexity of the free-space FMM, where N is the number of conductor patches. [ABSTRACT FROM AUTHOR]

The range profile is an easily obtainable and promising feature vector for a real-time radar target recognition system. However, the range profile is highly dependent on the aspect angle of a target. This dependency makes the recognition over a wide angular region difficult. In this paper, we propose a classifier with a subclass concept in order to solve this dependency problem. Recognition results with six aircraft models measured at a compact range facility are presented to show the effectiveness of the proposed classifier over a wide-angular region. [ABSTRACT FROM AUTHOR]