Reconfigurable antennas have a wide variety of applications in modern communications systems that require antennas with a dynamically adjustable radiation patterns. An interesting concept known as a refiectarray antenna has significant potential in meeting this need if it could be made to be electronically tunable. The design of such an antenna is the focus of this thesis.

The thesis makes a contribution in several areas related to the design and analysis of electronically tunable refiectarray antennas. First, the thesis presents a design and modelling technique for a novel reflectarray element exhibiting the phase agility required in reconfigurable antennas. The models allow the dynamics of the element to be understood while simultaneously accurately predicting its scattering behaviour. Second, the thesis explores the analysis of refiectarrays as a whole, with particular emphasis on techniques for predicting array-level effects that have not been previously addressed in detail in the literature. These effects include the specular reflection behaviour and transient response of reflectarrays.

Finally, the thesis presents several experimental prototypes of refiectarrays based on the proposed unit cell topology. The measured performance of the antenna correlates very well with theoretical expectations. Experiments with the electronically tunable refiectarray demonstrate excellent beam-forming characteristics, and validate the concepts and models presented in this thesis.