Dispersion characterisation of a composite right-left-hand transmission line unit cell using Particle Swarm Optimisation

The left-handed propagation behaviour of artificial metamaterial structures offers a new paradigm for electromagnetic device design. Transmission line metamaterials consisting of a cascade of identical unit cells have been shown to achieve wider bandwidth and lower losses than resonant left-handed structures. In this paper we demonstrate a method for extraction of the broadband dispersion characteristic of a single unit cell using Particle Swarm Optimisation of the unit cell's equivalent circuit component values.