摘要:

The fields due to a magnetic dipole on the ground plane with a dielectric cover are derived. Based on this knowledge, the mutual coupling admittance between radiating edges of a microstrip antenna with a dielectric cover layer is obtained by modelling the edge fields as equivalent magnetic currents divided into small sections. Experimental results verifying the proposed method are presented.

ISSN:0272-6343    

DOI:10.1080/02726348908915238

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The propagation in a non-linear dispersive medium is analysed by using differential equation techniques. A dispersive semi-infinite space with a cubic order instantaneous non linearity, is considered. The proposed analysis is based on to transform time dependent Maxwell equations into a slowly varying envelope function differential equation. The derived partial differential equation has many similarities with the so-called Schrödinger equation but it includes an additional term arising from the first order dispersion. This non-linear equation is solved by application of the Inverse Scattering Method for the initial condition |q(x,t = O)| = Asechx. The N-soliton solution is developed analytically in the case of reflectionless potentials. The single and double soliton solution are derived explicitly. Numerical results presenting the pulse propagation inside the non-linear dispersive medium are also given.

ISSN:0272-6343    

DOI:10.1080/02726348908915239

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The circular waveguide antenna feed with multiple coaxial cups is analyzed using the method of moments. The radiation properties of this type of prime focus feed are examined with particular emphasis on the level of cross-polarized radiation. It is demonstrated that by optimizing the feed dimensions the cross-polarization can be maintained below − 27 dB over a 20% bandwidth for a feed with a single coaxial cup.

ISSN:0272-6343    

DOI:10.1080/02726348908915240

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

By using a second order generalized impedance boundary condition to model the effect of a thin dielectric coating, the problem of a plane wave incident on a coated right-angled wedge is considered. The solution is derived using an extension of Maliuzhinets' method in which a key role is played by the particular solution of the difference equation for the spectral function. It is verified that the field satisfies the reciprocity and edge conditions, and the diffracted, geometrical optics and surface wave contributions are determined.

ISSN:0272-6343    

DOI:10.1080/02726348908915241

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

For large scatterers whose operator is discretized by a prohibitively large matrix. It may be advisable to build the solution in a gradual manner while relying on previously known information on a portion of the body. In this way, rather than analyzing the large composite body, a succession of calculations of small additions is carried out, starting at the point where the partial solution is known. The “Add On” method, introduced recently, has done this successfully for a number of large planar problems. The method reconstructs the matrix solution without building the entire matrix up and without inverting It. A companion formulation, based on matrix partitioning, is used in this work to compare the “Add-On” technique with the matrix formulation. It is shown that the two formulations yield the same results. However, the numerical advantages of the “Add On” technique are clearly shown, especially with regard to storage problems, since the full N × N matrix need not be generated and stored. Instead, the responses to P sources are handled, making the storage requirements similar to an N × P matrix, where P is typically much smaller than N. Speed advantage is also seen In this method, where the maximum amount of computations, assuming no previously known Information, is proportional to N2or N2.5, depending on the problem at hand. Examples with up to 6000 unknowns have been worked out and are presented below.

ISSN:0272-6343    

DOI:10.1080/02726348908915242

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor