Generation of inhomogeneous electromagnetic waves by a lossy prism

Abstract

The generation of inhomogeneous electromagnetic waves in free space is associated to the leaky-wave antennas. On the other hand, in the present paper, we show how an inhomogeneous wave can be also generated by the transmission of a homogeneous wave incident on a dissipative material with a spatial inhomogeneity. In fact, if we consider a dissipative material immersed in free space, with the first interface illuminated by a homogeneous wave, the spatial inhomogeneity gives to the wave different attenuations in the transverse direction; consequently the wave obtains an attenuation component tangential to the second interface, that imply the generation of an inhomogeneous wave in the free space. In particular, we consider a prism made of dissipative material illuminated by a horn tapered antenna. We present the phase and attenuation vectors' magnitudes, and the transmission angle of the inhomogeneous wave. The phase and attenuation vectors showing a strong dependence on the incident angle. Moreover, we found the optic path of the wave inside the prism during multiple reflections, in order to find the positions of the secondary lobs of the antenna. The possibility to generate inhomogeneous waves with strong attenuation finds applications for the deep penetration of electromagnetic waves in lossy materials.