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In this paper we consider the propagation of transverse-magnetic (TM) (HZ=0, E_{Z}\neq0) electromagnetic waves in an ideal regular waveguide of arbitrary cross section. It is assumed that the permittivity and permeability of the magnetodielectric filling of the waveguide are functions of the coordinate and time (\varepsilon(z, t), \mu(z, t)). From the system of Maxwell equations, the wave eq...Show More
A finite-element formulation for electromagnetic waveguide problems is described using the transverse electric field component. In this approach, the electric field components can be directly obtained as an eigenvector of a matrix eigenvalue problem. Furthermore, no spurious solutions are involved in the entire region of a propagation diagram, and the dimension of the final matrix equation is redu...
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Laser driven terahertz radiation sources have been developed to enable energy modulation of relativistic electron bunches on a sub-picosecond timescale. Photoconductive and nonlinear optical generation schemes capable of providing the required > 1MV cm-1 field strengths, and longitudinal polarisation components, are discussed.Show More
This paper compares power-amplifier-inserted transversal filter (PAITF) with 180° hybrids and T-junctions for envelope pulse-width modulation (EPWM) transmitters on power efficiency and modulation accuracy. A computer simulation that combines digital signal processing and microwave circuit simulation shows no significant difference between the transmitters with the two power combining methods. How...Show More
The electric field of the modes of rectangular dielectric waveguides is known to diverge in the corners of the waveguide. An accurate numerical computation of the vector mode fields for a sample waveguide exhibits clear signs of this divergence. The divergence makes the design of rapidly converging numerical algorithms for vector mode field computations difficult.<>Show More
The behavior of the field components near the edge has been shown to be that of the static fields, which is derived here without rigor for an infinite wedge. Fields scattered by a finite dielectric wedge illuminated by an arbitrary plane monochromatic wave are computed using either singular or hypersingular integral equations (SIEs or HIEs), derived by the single integral equation method. Field co...Show More
An attempt is made to present unified, cohesive, and complete derivations of the classical representations of solutions to Maxwell's equations. The traditional arguments are reviewed with an eye towards generality, as regards the assumptions about the nature of the medium and the source terms. In this manner very specific results are obtained categorizing the existence, universality, and utility o...Show More
The homogeneity of the transverse electromagnetic (TEM) field in a TEM device is a necessary condition for the compliance of emission and immunity measurements in TEM test facilities with standards. Under these conditions, the behavior of the TEM mode over the desired frequency range has to be verified. This homogeneity, indeed a figure of merit of the waveguide, is investigated using the generali...Show More
A power-amplifier filter architecture is described in which a switching-mode power amplifier with pulse density modulation is inserted in each path of a transversal filter. This filter suppresses the quantization noise that remains at the output of the component power amplifiers as well as amplifies the signal with high efficiency. The center frequency and pass bandwidth of the filter can be varie...Show More
Radar is a device which detects distant or non visible objects by means of reflected radio waves. The quality of the reflected signal depends on the shape and orientation of the target with respect to the type of polarization used. Most of the antennas currently used on radar systems employ one type of polarization at a time for target detection. This paper describes the importance of employing po...Show More
The mode theory of the strongly anisotropic a axis step-index single-crystal fiber is studied in this paper. The electromagnetic field equations of the a axis step-index single-crystal fiber are solved under the strongly anisotropic condition, and the transverse electric field components are obtained. The dispersion equations far from cutoff, near cutoff, and in the guided mode region are discusse...Show More
Three YBCO coated conductors with various critical currents, up to 189 A, were prepared. The magnetization losses without transport current and the total AC losses of the conductors carrying various transport currents in transverse magnetic fields with various orientations were measured electromagnetically to study the AC loss characteristics systematically. The measured total AC losses were compa...Show More
The transverse component of magnetic flux intensity is pivotal that affect the utilization rate of target material and quality of deposition film as well as the instability of the sputtering process. The distribution of transverse component of magnetic flux intensity on the surface of the target was calculated by means of the finite element method. Furthermore, the experiment distribution of the t...Show More
A rigorous analysis of the electromagnetic guiding properties of three-layer, coaxial, dielectric-loaded cylindrical waveguides is presented. It is shown that three types of modes can exist on the structure: transverse electric, transverse magnetic, and hybrid. Explicit expressions for the characteristic equation are presented, and numerical methods of solution are discussed. The numerical results...
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In this paper, a new type of antenna arrays, that is, a twelve-element CTS antenna array is discribed. The Continuous Transverse Stub (CTS) array represents a unique class of array antenna that exploits the low-loss, low-dispersion, dimensional robustness, and design flexibility of an open parallel-plate structure as both its transmission-line and radiator basis. The design of the CTS array was op...Show More
A theoretical study of TE-wave propagation in a hollow circular waveguide with a graded dielectric medium is presented. The medium is modeled using a squared cosine function that oscillates between two unique complex dielectric media to simulate a periodic multilayer structure. The proposed model is applicable to arbitrary complex permittivities of the two media, including negative values for chir...Show More
The expressions of the transverse electric (TE) and transverse magnetic (TM) modes of the isosceles right triangular waveguides with unusual boundary conditions are discussed in this paper. Based on the initial solution formed using a finite sum of rectangular harmonics, boundary conditions are discussed, and TE and TM mode expressions are presented in this paper for the isosceles right triangular...Show More
The aim of this study was to compare the knee kinematics of anterior cruciate ligament reconstructed (ACL-R) and healthy subjects (CG) during gait and classify the status of normality. Ten healthy and six ACL-R subjects had their gait analyzed at 60 fps. 3D knee angles were calculated and inserted into three separate matrices used to perform the principal component (PC) analysis. The scores of PCs...Show More
Electromagnetic fields in homogeneous source-free regions can be decomposed into fields that are TE and TM with respect to a particular reference direction (e.g., the z direction). If transverse sources exist, both TE and TM fields may be excited simultaneously. This paper considers the case of two infinite regions having a common planar interface and prescribed sources (surface currents) on the i...Show More
The torque and unbalanced magnetic forces in a small flux concentrating permanent magnet transverse flux machine (FCPM-TFM) in segmented compact structure, which are the resultants of the tangential; axial and normal magnetic forces, respectively, are in general influenced by pole-teeth-winding configuration. The paper calculates the torque and unbalanced magnetic forces using finite element (FE-)...Show More

Site-specific strong ground motion prediction using 2.5-D modelling

Geophysical Journal International
Year: 2001 | Volume: 146, Issue: 2 | Journal Article |
An algorithm was developed using the 2.5-D elastodynamic wave equation, based on the displacement–stress relation. One of the most significant advantages of the 2.5-D simulation is that the 3-D radiation pattern can be generated using double-couple point shear-dislocation sources in the 2-D numerical grid. A parsimonious staggered grid scheme was adopted instead of the standard staggered grid sche...Show More

Site-specific strong ground motion prediction using 2.5-D modelling

Year: 2001 | Volume: 146, Issue: 2 | Journal Article |

Evaluation of time domain electromagnetic fields radiated by constant velocity moving particles traveling along an arbitrarily shaped cross-section waveguide using frequency domain Green's functions

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Radio Science
Year: 2012 | Volume: 47, Issue: 05 | Journal Article |
A technique for the accurate computation of the time domain electromagnetic fields radiated by a charged distribution traveling along an arbitrarily shaped waveguide region is presented. Based on the transformation (by means of the standard Fourier analysis) of the time-varying current density of the analyzed problem to the frequency domain, the resulting equivalent current is further convolved wi...Show More

Evaluation of time domain electromagnetic fields radiated by constant velocity moving particles traveling along an arbitrarily shaped cross-section waveguide using frequency domain Green's functions

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Year: 2012 | Volume: 47, Issue: 05 | Journal Article |
Summary form only given. For higher order mode excitation in a system with a cylindrical symmetry such as a cylindrical waveguide, a higher order Bessel function is required and numerically an expansion of this function in terms of a series is mostly used. However, the accuracy of mode pattern excited is getting worse when one pushes it to higher and higher order mode with a limited number of expa...Show More
The spectral-domain technique is utilized to analyze the coupling characteristics of coplanar waveguides and microstrip lines coupled with multilayer lossy dielectric media. Numerical results illustrating the dispersion characteristics of coplanar and microstrip lines, as well as the various electric field components coupled to highly lossy dielectric media, are presented. It is shown that the pre...Show More