Investigation on the relation between dispersion diagram and the radiation pattern of low-profile antennas

The development of wireless communications has recently led to a great demand of low-profile antennas. Presently, research studies are exploiting antenna configurations whose design is based on a radiating element placed in close proximity of a high impedance surface (HIS), acting as an artificial magnetic conductor (AMC) as well as an electromagnetic bandgap (EBG) surface. In this paper we focus our attention on the comprehension of the interaction mechanisms arising between the radiating element and the HIS with the aim of deriving useful criteria for future designs. In particular, the role of the HIS has been investigated in terms of its AMC and EBG properties; finally, the effect of the reflecting surface on a wide band antenna performances (in terms of input-matching and radiation pattern) has been analyzed.