## 1. Introduction

[2] Anisotropic media are extensively utilized in electromagnetic modeling and design due to their directionally dependent properties. In *Luo et al.* [2006], a modulated Gaussian beam transmitted into an anisotropic metamaterial with special dispersion relation exhibits a superluminal group velocity for the peak of the wave packet. In addition, anisotropic substances, comprised of periodic lattices and wires, that demonstrate negative refraction and focusing have been reviewed and presented [*Fang et al.*, 2009]. An optical backward-wave bianisotropic composite medium matched to free space is also suggested in*Tretyakov et al.* [2007] suitable for operation in the optical range where artificial magnetism is not easily achieved. Furthermore, interesting properties of an infinite homogeneous circular cylinder with full permittivity tensor, excited by a straight strip of arbitrary axial magnetic current, have been examined [*Valagiannopoulos*, 2007b]. It has been finally shown that a metal film with an one-dimensional array of subwavelength slits can be accurately designed with use of anisotropic and non-dispersive substances [*Shin et al.*, 2006].

[3] On the other hand, structures with nonparallel boundaries such as wedges, junctions, and tapered waveguides are employed in numerous theoretical considerations and actual experiments because of their receptivity to semi-analytical treatment and their simplicity in construction. In*Nefedov and Tretyakov* [2011], the wedge of an ultra-broadband electromagnetically indefinite medium, formed by aligned carbon nanotubes is employed to transform incident evanescent waves into propagating transmitted modes. The wavefront-tilt effect in nonparallel optical waveguides, caused by junctions in the input and output of the filter, is also treated with help from mode-matching methods [*Huang and Lessard*, 1992]. Furthermore, the operation of conical horn antennas has been investigated in *Hamid* [2003], where edge modification and wall corrugation are utilized to improve its radiation characteristics. Corners owned by devices with polygonal shape existing in any laboratory of electromagnetics, are modeled with two nonparallel metallic planes to proposed ways of reducing the singular field concentration along the edges [*Valagiannopoulos*, 2009]. Surface waves transmitted through prismatic structures composed of birefringent media, have been also theoretically explored in *Takayama et al.* [2011], where unexpected high transmission above the critical angle is predicted.

[4] In this work, we combine the two aforementioned topics (anisotropic materials, nonparallel boundaries) to formulate a simple, iterative method that solves the scattering problem defined by the plane wave excitation of an anisotropic prism. The structure is comprised by a front and a rear planar surface, nonparallel each other, and therefore is not possible for a single wave to satisfy simultaneously the necessary boundary conditions along both of them. Accordingly, we solve each time a partial, simplified boundary value problem along one surface by ignoring the presence of the other. In fact, we repeatedly treat each incidence-reflection-transmission effect as if the prism was infinitely extended toward the one or the other horizontal direction. The solution to the total problem is given as the sum of the corresponding partial solutions. In this way, the method does not take into account the effect of the edge and therefore is better applicable for points far from the crossing point of two surfaces. The average error at the boundaries of the prism, indicating the performance and the effectiveness of the technique, is represented with respect to geometrical and excitation parameters. The transmission through the device is investigated via a newly defined ratio whose variations with respect to the features of the structure are shown and discussed.