摘要:

Previous papers have determined the corner correction for axial current in a conducting wedge with an internal right angle. The corner constant for transverse current is now defined to correct the power dissipation of the simple impedance solution at the corner. Previous results are used to calculate its value for the case of an internal right angle in this paper. For arbitrary internal angles an integral representation is found for the transverse corner constant; it is used to obtain the transverse corner constant in the case of an external right angle. Furthermore, it is also briefly shown how the corner corrections for both axial and transverse current apply to the calculation of the propagation constant in a waveguide.

ISSN:0920-5071    

DOI:10.1163/156939396X00865

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The technique of separation variables combined with boundary-value method and additional theorem for the cylindrical wave functions is employed to examine the multiple scattering from two infinitely long, parallel, non-erlapping circular impedance cylinders eccentrically coated with Faraday chiral media at normal incidence. Parametric study is performed to show the effects of constitutive and geometrical variables as well as the incident wave direction on the scattering cross section and other scattering characteristics of two composite eccentrical cylinders. It is believed that the present study provides us some insight into the physical properties of Faraday chiral coatings.

ISSN:0920-5071    

DOI:10.1163/156939396X00874

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this paper, an analysis of VLSI interconnetions of a cylindrical multiconductor microstrip transmission line (MMTL) in a multilayered dielectric media based on finite and infinite element methods is presented. An approach is proposed for electromagnetic modeling of cylindrical MMTL (CMMTL) used in circuit simulations. This development is based on the assumption that the finite circuit transverse dimensions are comparable with the operating wavelength and quasi-TEM mode can be applied. A Maxwellian capacitance matrix per unit length (MCMPUL) is derived using energy functional formula of the Laplace's equation. The network equations are also derived applying the modified nodal admittance (MNA) method. The most useful parameters, e.g., modal characteristic impedance, normal mode propagation constant, effective dielectric constant, and networking function are obtained in terms of the MCMPUL. Numerical results are compared with those obtained by means of series expansion method. It is found to agree with other investigated results.

ISSN:0920-5071    

DOI:10.1163/156939396X00883

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Altimetric height can be underestimated on ice sheet surfaces, because of penetration of the radar wave inside the snowpack. Estimation of the induced bias is quite impossible, because of the large number of parameters involved both in surface and subsurface scattering. Indeed, altimetric echo of snow surface is controlled by antenna pattern, surface microroughness and kilometric roughness, internal stratification, scattering and extinction coefficient. Most of these parameters are radar frequency dependent, the dual-frequency Topex altimeter thus gives an opportunity to empirically detect this bias. Indeed, volume signal is clearly suggested by comparing the C-band and Ku-band altimeter heights and waveform parameters. Altimeter height difference are of a few decimeters only, and have kilometric scale variations: induced volume error seems to be more linked with the waveform deformation by the surface topography than with the intensity of the subsurface signal.

ISSN:0920-5071    

DOI:10.1163/156939396X00892

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Reflection and transmission coefficients for an electromagnetic wave are usually computed using the frequency representation: a monochromatic plane wave decomposition [1-2]. Even though this method is a powerful tool, the physical meaning can be hidden by some mathematical complexity coming from Fourier integrals, complex analysis and matrix manipulation. Furthermore, the Maxwell equations, when the fields are only dependent on x and t, are very simple and can be solved using elementary calculation [3]. It will be shown that the physical propagation mechanism, which includes initial conditions, transmission and reflection, can be completely built up within the space-time, rather than in the frequency domain. This would shed a new light on traditional well known results.

ISSN:0920-5071    

DOI:10.1163/156939396X00900

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Three methods to obtain compromised sets of excitations in monopulse antenna arrays are investigated. The techniques involve minimizing a scalar-valued performance measure, called cost function, via the use of simulated annealing method. The unknowns in the cost function are the weight factors of each sub-array or the relative amplitudes and the phases of the excitations of the array elements. Several examples are presented to illustrate the optimal results obtained.

ISSN:0920-5071    

DOI:10.1163/156939396X00919

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939396X00928

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939396X00937

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor