Optically Controlled Leaky-Wave Antenna Based on NRI-TL Metamaterials

We propose the optical control of a negative-refractive-index-transmission-line leaky-wave antenna. This is achieved by implementing optically controlled varactors in the unit-cell structures of the negative-refractive-index-transmission-line leaky-wave antenna. The optically controlled varactors consist of a photodiode and a transimpedance amplifier. By using this topology, the intensity of light is converted into photocurrent at the photodiode and then into voltage at the transimpedance amplifier. Therefore, the capacitance of the varactors can be controlled by varying the incident light intensity at the photodiode. This enables us to control the time delay of each negative-refractive-index-transmission-line unit-cell and therefore steer the radiation beam of the leaky-wave antenna.