Numerical evaluation of electromagnetic-wave penetration at normal incidence through an inhomogeneous-wave approach

This paper presents numerical scenarios concern-ing penetration in a lossy medium that can be obtained by radiating inhomogeneous electromagnetic waves. Former pa-pers approached this problem, both analytically and numeri-cally finding requirements and limits of the so-called \deep-penetration' condition, which consists of a wave transmitted in a lossy medium having an attenuation vector whose direc-tion forms the angle of ninety degrees with the normal to the separation surface. The deep-penetration condition always re-quires an oblique incidence, therefore is not practical in many applications. For this reason, we are interested here in finding whether an inhomogeneous wave guarantees larger penetra-tion than the one obtainable with homogeneous waves, even when the incident wave is normal to the separation surface between two media, i.e. when the deep-penetration condition is not satisfied. We are also interested in verifying numer-ically whether the lossy-prism structure may achieve larger penetration than the one obtainable through traditional leaky-wave antennas, and we also wish to propose a lossy-prism de-sign more realistic than the one previously presented in the literature.