UTD solution for the diffraction by an anisotropic impedance wedge at arbitrary skew incidence: Numerical matching method based the revision of Maliuzhinets function

Abstract

The previous numerical matching method can't apply in the whole angle space (0° ≪ β 0 ≪ 90°) whether only based on the normal incidence case nor based on grazing to the edge incidence case when solving the diffraction problem of the anisotropic impedance wedge at oblique incidence by plane wave. A revised numerical matching method (NMM) based on the framework of the uniform geometrical theory of diffraction(UTD) is proposed to build the spectral functions for computing the diffraction field by anisotropic impedance wedge at an arbitrary skew incidence. Firstly, Maliuzhinets function for the skew incidence is revised according to the physical meaning of spectral functions. The satisfactory Maliuzhinets function is obtained when the skew incidence angle is large deviations from normal incidence. Then the UTD solutions of the anisotropic impedance wedge at arbitrary sampled skew incidence (0° ≪ β 0 ≪ 90°) can be obtained by applying the revised NMM based on the normal incidence only. For efficiency consideration, the spectral functions of a few number of incident angles are derived with NMM and set as the sampled data set. Thirdly, on the basis of these sampled incidence cases, the Asymptotic Waveform Evaluation (AWE) technique is employed to construct the spectral function at any other skew incidence in the whole angle space rapidly and the UTD solutions at arbitrary unsampled skew incidence are obtained with revised NMM. Finally, the validity of the numerical results is established by comparison with the MM-PO hybrid method. The proposed revised NMM-UTD solution overcomes the standard limitation of applied angle of the previous NMM.