Numerical Evaluation of Electromagnetic-wave Penetration at Normal Incidence through an Inhomogeneous-wave Approach

摘要

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.