An idea for electromagnetic "feedforward-feedbackward" media

In this paper, an idea for a new class of complex media that we name feedfo rward-feedbackward (FFFB) media is presented and some of the results of our theoretical work in analyzing plane wave propagation in the axial directio n through these media are described, The concept of FFFB media, as introduc ed here, was inspired by the theoretical research of Saadoun and Engheta on a variation of artificial chiral media. Like chiral media, to our knowledg e there are no naturally occurring FFFB media for the microwave frequency b and; for this reason we introduce an idea for artificial FFFB media. The fo cus of this paper is on one conceptualization of such media, namely dipole- dipole FFFB media. First, we present the calculation of the necessary const itutive parameters for studying axial plane wave propagation. Then we solve the macroscopic Maxwell equations in the k domain for axial plane wave pro pagation in an unbounded source-free crossed-dipole FFFB medium. Finally, w e present the dispersion equation for this medium in this case, discuss som e of the physical properties of its roots and certain features of the polar ization eigenstates, and briefly speculate some of the potential applicatio ns of this medium.