摘要:

Uniform asymptotic Physical Optics diffraction coefficients for an anisotropic half-plane illuminated at oblique incidence are given in this paper. From the electromagnetic viewpoint such a structure is characterized by suitable anisotropic impedance boundary conditions. The principal axes of anisotropy can be not coincident with the half-plane edge. The solution is obtained by using a Physical Optics approximation of the equivalent surface current densities on the half-plane and by performing an uniform asymptotic evaluation of the radiation integral. Some numerical results are reported to demonstrate the effectiveness of the proposed approach.

ISSN:0920-5071    

DOI:10.1163/156939399X00439

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Open-end of a waveguide or a window backed by a waveguide can be used as an EMI sensor. A Moment Method analysis of such sensors, illuminated by an uniform plane wave incident from any direction in space is presented. The antenna factor of the sensor i.e., the incident electric field required to generate an input voltage at the measuring port of the sensor, is derived. Numerical and experimental data are presented for open-ended waveguide sensor, thick window sensor and dielectric backed waveguide sensor. The results are also compared with an empirical antenna factor formula used by EMC practitioners. The experimental results show a very good agreement with the theoretically predicted data.

ISSN:0920-5071    

DOI:10.1163/156939399X00448

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

An electromagnetic wave scattering model based on a hybrid SPM/MoM technique has been developed for the study of the EM wave interaction of a conducting object above a rough surface. In this hybrid technique, the Green's function and surface variables are expanded in terms of the surface height function on the mean surface, so that the integral equations based on the extinction theorem and boundary conditions can be decomposed into different orders. Each order represents the problem of EM wave scattering from an object on a flat interface excited by a wave from an equivalent source. With the introduction of the dyadic Green's function for layered media, the integral equations are reformulated and solved without involving the surface variables on the interface. Since the returned fields using the hybrid technique are expressed term by term, the EM wave interaction of the object with the rough surface can be clearly identified and characterized. The total returned fields calculated by the hybrid technique, which are the sum of individual interaction terms, are compared with simulation results computed with the standard MoM, and good agreement is obtained.

ISSN:0920-5071    

DOI:10.1163/156939399X00457

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The major defects of the Woodward-Lawson method of shaped pattern synthesis (lack of control over side lobes and ripple, and high dynamic range ratios) can be overcome by perturbing the field samples weighting the component sin(Nx)/sin(x) beams. If a real field is not necessary, further improvement (especially as regards dynamic range ratio) can be achieved by optimizing the phases of the coefficients of the component beams. These procedures are illustrated by linear arrays producing a symmetric flat-topped beam and a cosecant squared pattern.

ISSN:0920-5071    

DOI:10.1163/156939399X00466

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

An integral equation for electrostatic field in inhomogeneous medium is deduced by employing dyadic Green function. On this basis the strong fluctuation theory is build for electrostatic field. It is shown that the theory gives the Bruggeman formula for effective permittivity in zero order of perturbation theory. The accuracy of the strong fluctuation theory is analyzed.

ISSN:0920-5071    

DOI:10.1163/156939399X00475

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939399X00484

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939399X00493

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor