High-frequency Green's function for a semi-infinite array of electric dipoles on an infinite grounded stratified dielectric slab: part III $phase-matched wave interactions and numerical results

Abstract

The particular effects of phase matching in interactions between different wave species and interaction mechanisms pertaining to the asymptotic Green's function for a semi-infinite phased array of parallel dipoles on an infinite grounded stratified dielectric slab are addressed. The two previous parts have lead to a grouping of certain asymptotic terms, which provides physically appealing interpretations of interacting wave processes that involve slab-modulated propagating (radiating) Floquet waves (FW), slab-guided leaky waves (LW), evanescent (nonradiating) FWs and surface waves (SW), together with their associated conical edge-coupled wave constituents. Special attention is now given to the role, in these wave interaction functions,of the difference between the propagating wave numbers (i.e., the degree of phase matching) that characterizes any pair of propagating FWs and LWs, and evanescent FWs and SWs. Cutoff transitions of FWs from the evanescent to the propagating regime are described also in terms of a second wave interaction function, structured similarly to the first. In connection with applications, the interaction between SWs and evanescent FWs, as well as FW transitions from evanescent to propagating, are discussed from the perspective of scan blindness in actual arrays. Various numerical studies highlight the role of phase matching in different problem scenarios.