Electrically controllable metamaterials based on 2D wire media

Electromagnetic waves in an artificial medium formed by two mutually orthogonal lattices of thin reactively loaded wires (referred to as 2D loaded wire medium (2D LWM)) are considered. In the assumption of a small distance between the loads compared with the wavelength, the loads are taken into account via a distributed surface impedance of the wires. We demonstrate how the directions of phase and group velocities in 2D LWM can be controlled by tunable capacitive loads. Such electrically controllable metamaterials can find applications for example in tunable antenna lenses.