The paper describes the application of the finite-differencemethod in the timedomain for obtaining the cutoff frequencies of TE and TM modes in waveguides of arbitrary cross-section. Maxwell's equations are disc...
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The paper describes the application of the finite-differencemethod in the timedomain for obtaining the cutoff frequencies of TE and TM modes in waveguides of arbitrary cross-section. Maxwell's equations are discretised in a two-dimensional space. The application of the discrete Fourier transform also provides the spatial distribution of the modes in the cross-section of the waveguide. The method is validated against rectangular and a circular waveguides, each with a known cutoff spectrum. Finally, the method is applied to determine cutoff wavelengths and modal field distributions in a square coaxial waveguide
An absorbing boundary condition is given for the application of the pulsed incident electromagnetic field form of the finitedifferencetime-domainmethod to the analysis of waveguide discontinuities. Its application i...
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An absorbing boundary condition is given for the application of the pulsed incident electromagnetic field form of the finitedifferencetime-domainmethod to the analysis of waveguide discontinuities. Its application is illustrated by example.
The finite-differencetime-domain (FD-TD) method is proposed as a means of accurately computing electromagnetic scattering by arbitrary-shaped extremely complex metal or dielectric objects excited by an external plane...
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The finite-differencetime-domain (FD-TD) method is proposed as a means of accurately computing electromagnetic scattering by arbitrary-shaped extremely complex metal or dielectric objects excited by an external plane wave. In the proposed method, one first uses the FD-TD method to compute the near total fields within a rectangular volume which fully encloses the object. Then, an electromagnetic-field equivalence principle is invoked at a virtual surface of this rectangular volume to transform the tangential near scattered fields to the far field. To verify the feasibility of this method, the surface currents, near scattered fields, far scattered fields, and radar cross section of two canonical two-dimensional objects are presented. For these cases, it is shown that the FD-TD method provides magnitude of current and field predictions which are within ± 2.5 percent and further phase values within ± 30 of values predicted by the method of moments ( MOM) at virtually every point including in shadow regions.
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