摘要:

A systematic development is presented of three distinct mixed-potential integral equations for the analysis of printed circuits, microstrip resonators, and antennas embedded in multi-layered, planar, uniaxial media of infinite lateral extent, with emphasis on microstrip structures comprising non-planar conductors of irregular or arbitrary shapes.

ISSN:0920-5071    

DOI:10.1163/156939393X00101

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An analysis of scattering of transverse electric (TE) illumination by inhomogeneous lossy dielectric/ferrite cylinders near a planar media interface by employing the hybrid surface/volume integral equation method is presented. The inhomogeneous cylinders are of general cross section, of infinite extent, and their axes are parallel to the interface. Coupled hybrid integral equations are formulated and a numerical method is developed for solving them. In the formulation of the hybrid integral equations, both the surface equivalence principle and the volume equivalence theorem are employed, and attention is focused on minimizing the computation of Sommerfeld integrals and on reducing the number of unknowns. From the numerical solution of the equivalent surface current, the far-zone scattered field is calculated. Data depicting the equivalent current distribution and the far-zone field patterns are presented and discussed for various cylinder and half-space parameters.

ISSN:0920-5071    

DOI:10.1163/156939393X00110

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In this paper, first a detailed derivation of the Singular Integral Equation (SIE) method for application to finlines on isotropic substrates is given. The formulation is largely based on the one given by R Mittra et al. [1] for the microstrip line. The derivation is validated by computing the propagation constants of the dominant and higher order modes of bilateral finline. Next, simple perturbation formulas are given to extend the above SIE derivation to obtain the propagation constants of finlines containing anisotropic material. Numerical results are given for the propagation constants of finlines containing either an anisotropic dielectric substrate or a magnetized ferrite.

ISSN:0920-5071    

DOI:10.1163/156939393X00129

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Microwave radiometers, operating at 3.95, 19.5, 37.5 and 150 GHz and placed in a tower, were used for snow measurements during the winters of 1985-1989. The effects of snow structure, wetness, and grain size were examined in detail. The emissivity of snowpack has been calculated by a quasi-static method and by applying the equation of radiative transfer. The latter takes into account the physical-mechanical properties of the real snowpack obtained by direct glaciological methods. The experimental data are compared against theoretical results. The quasistatic model is shown to be adequate for f < 20 GHz whereas the radiative transfer model agrees for f < 150 GHz, especially when the size distribution of ice particles in snow is included.

ISSN:0920-5071    

DOI:10.1163/156939393X00138

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Image theory, previously developed for the analysis of a conducting half plane by the present authors, is extended to problems involving a conducting wedge. It is shown that the classical two-dimensional electromagnetic field problem of a perfectly conducting wedge can be solved by interpreting the contribution due to the wedge as arising from a suitably defined image source consisting of a discrete and a continuous part located in complex space. The image currents give the exact field, do not depend on the point where the field is calculated and can be expressed in terms of simple trigonometric functions in contrast to more complicated functions characterizing the physical surface currents on the wedge or non-physical approximate currents applied in the Physical Diffraction Theory. Also, the image theory applies to the corner reflectors of any corner angle. The classical image theory with discrete images for corner angles of the form π/n is obtained as a special case.

ISSN:0920-5071    

DOI:10.1163/156939393X00147

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Cassegrain antennas have been utilized in applications where small size is critical. It has been observed that for antennas having subreflectors of the order of only several λ in diameter, near-in sidelobe levels rise beyond normally predicted values. E-plane sidelobes are often several dB higher than those in the H-plane. Disturbances in the illumination of the primary reflector due to diffraction limitations of the electrically small subreflector are a possible cause of the sidelobe phenomenon. In this work, the results for 3 to 8 λ -diameter hyperboloidal subreflectors, using the geometrical theory of diffraction (GTD) are presented and compared with the physical optics approach and other data. Degradation of the scatter patterns are observed as the subreflector size is decreased, and the differences in the E-and H-plane phase and amplitude patterns are observed in the GTD solution.

ISSN:0920-5071    

DOI:10.1163/156939393X00156

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In this paper, a formulation for the dyadic Green's function of cylindrical multilayered chiral media is presented at first using the methods of eigenfunction expansion and scattering superposition. The specific expressions of the dyadic Green's function are also found in terms of normalized cylindrical vector wave functions, when the electric current sources are placed both inside and outside of a chiral circular cylinder and a cylindrical chirodome. The radiation characteristics of a point dipole antenna on the axis of chiral circular cylinder and cylindrical chirodome are analysed. For both cases, the results show that by changing the size of chiral circular cylinder, the thickness of cylindrical chirodome and the parameters of chiral media, purely circular and linear polarization can be obtained in the far field. Also, the expressions of dyadic Green's function given in this paper can be directly used to analyse the radiation characteristics of cylindrical chirostrip antennas.

ISSN:0920-5071    

DOI:10.1163/156939393X00165

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939393X00174

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939393X00183

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor