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The present paper gives an interaction of electromagnetic waves with a smooth convex tri-angular obstacle and its adjacent wedge regions. We attempt to find the power of groove fields under Dirichlet conditions associated with axisymmetric electromagnetic field. A field intensity may be expressed in terms of a damped wave with a space attenuation depending on the physical parameters like conductivity, permittivity and permeability associated with an obstacle placed across the lines of force due to a given EM field. Groove field and their associated powers based on Dirichlet conditions on the groove surfaces have been determined. Knowledge of groove field is essential for precise designing of triangular corrugated structures for studying the blazing effect of propagating EM wave. We find that an echellete model or an antenna may act as a Sensor for receiving wide range of frequencies subject to the restriction lambda>2pi/xi_i whereas the said antenna would act as a Transmitter for radiating wide range of frequencies subject to the restriction lambda<2pi/xi_i. The governing Maxwell's equation is solved subject to the Dirichlet condition of the field intensity on the boundaries of the said groove regions. Theory of Fourier-Bessel series has been applied for the present purpose., Comment: Conflict between authors

The present work is concerned with the propagation of electro-magneto-thermoelastic plane waves of assigned frequency in a homogeneous isotropic and finitely conducting elastic medium permeated by a primary uniform external magnetic field. We formulate our problem under the theory of Green and Naghdi of type-III (GN-III) to account for the interactions between the elastic, thermal as well as magnetic fields. A general dispersion relation for coupled waves is deduced to ascertain the nature of waves propagating through the medium. Perturbation technique has been employed to obtain the solution of dispersion relation for small thermo-elastic coupling parameter and identify three different types of waves. We specially analyze the nature of important wave components like, phase velocity, specific loss and penetration depth of all three modes of waves. We attempt to compute these wave components numerically to observe their variations with frequency. The effect of presence of magnetic field is analyzed. Comparative results under theories of type GN-I, II and III have been presented numerically in which we have found that the coupled thermoelastic waves are un-attenuated and nondispersive in case of Green-Naghdi-II model which is completely in contrast with the theories of type-I and type-III. Furthermore, the thermal mode wave is observed to propagate with finite phase velocity in case of GN-II model, whereas the phase velocity of thermal mode wave is found to be an increasing function of frequency in other two cases. We achieve significant variations among the results predicted by all three theories., Comment: 12 pages