摘要:

The complete eigenfunction expansion of the electric field dyadic Green's function in spherical coordinates is presented with particular attention given to the significance of the longitudinal eigenfunctions in this expansion. It is shown that the spectrum of the transverse eigenfunctions contribute zero frequency static like modes that cancel the longitudinal modes outside the source region. Inside the source region the cancellation is not complete but the non-cancelling part can be expressed as a delta function contribution in full agreement with the results obtained by Tai by a different method. Various representations for the dyadic Green's function in free space and in a spherical cavity are presented. The paper includes a brief historical survey of the development of the eigenfunction expansion method for the dyadic Green's function in order to highlight some of the early difficulties that were encountered.

ISSN:0272-6343    

DOI:10.1080/02726348608915211

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The conventional formulation of the electromagnetic field solution for a cylindrical dielectric rod is re-interpreted in a novel fashion in order to show the presence of surface waves which propagate over the rod's surface along helical paths. The solutions of the characteristic equation of the rod are interpreted in terms of the resonances at which these helical surface waves azimuthally match phases after each circumnavigation of the rod, effectively forming resonating standing waves around the rod. This interpretation permits us to obtain the pitch angle of the helix, and the dispersion curves (phase velocity as a function of frequency) of the helical surface waves.

ISSN:0272-6343    

DOI:10.1080/02726348608915212

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Kirchhoff Integration over a vertical aperture is used to obtain a simple expression for radio-wave propagation from a forest to a clearing. Numerical results are presented for a frequency of 10 MHz, and the classical recovery effect is observed. Numerical comparisons are made with a previous integral equation solution, and the agreement is good.

ISSN:0272-6343    

DOI:10.1080/02726348608915213

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Annular sector and circular sector microstrip antennas have been analyzed for input impedance and radiation patterns. The analytical technique used is the generalized transmission line method which has the advantage of estimating the phase of aperture fields correctly. Agreement between the theoretical and the measured characteristics of annular sector antenna are found to be good. Semicircular annular ring antenna appears to be promising.

ISSN:0272-6343    

DOI:10.1080/02726348608915214

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This article presents the solution to the heretofore unresolved problem of precise computation for the near field of printed circuits and printed circuit antennas on cylindrical substrates. The procedure involves a recurrence/continued fraction algorithm development for the evaluation of the Green's function pertinent to this particular configuration of printed circuit elements. With this new algorithm, arbitrary size cylindrical substrates can be modelled with an extremely high degree of accuracy. Computation of the input impedance of center fed and axially symmetric microstrip dipoles is used as an example. Excellent agreement is found for large cylinders with the limiting case of center fed microstrip dipoles on planar substrates.

ISSN:0272-6343    

DOI:10.1080/02726348608915215

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

It is shown that the disctete system solved by the Spectral Iterative Technique (SIT) is of Toeplitz or block Toeplitz form, and thus may be more amenable to direct solution in certain cases. In addition, the discrete system associated with the SIT is shown to be equivalent to a moment method matrix equation, with basis and testing functions chosen implicitly in the process. Thus, there is no additional generality in the SIT type of approach compared to the conventional method of moments. These statements concern the discretization procedure used within the SIT, and apply whether the SIT is implemented in its original form or in connection with the conjugate gradient method. Simple examples of scattering from a single strip and from a periodic array of strips are used to illustrate the concepts.

ISSN:0272-6343    

DOI:10.1080/02726348608915216

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor