Antenna beam forming using active metallic photonic band-gap materials

Abstract

Metallic photonic band-gap (MPBG) materials are periodic structures composed by metallic parts. The reflection characteristics of MPBG are dependent on the frequency. They exhibit bands in which there is no propagation mode inside the structure. The MPBG composed by continuous wires and the MPBG composed by discontinuous wires have different responses when excited by a normal incident plane wave. The MPBG excited with plane waves is given. In order to obtain the angular response, the structures are excited by an omni-directional antenna. To switch from continuous to discontinuous wires, active components can be added on the wires. Using just a few wires with active elements on it the beam shaped by the MPBG can be either turned on/off or shaped in different ways. The theoretical results are presented. In order to reduce the number of active elements or to have more possibilities, structures composed by both continuous and discontinuous wires are also presented. It is demonstrated that the behavior of these structures can approximately be deduced from the behavior of the different parts alone. Finally, a structure using continuous wires and discontinuous wires, on which active elements are implemented is presented.