A 740-GHz Dynamic Two-Dimensional Beam-Steering and Forming Antenna Based on Photo-Induced Reconfigurable Fresnel Zone Plates

We report a 0.74-THz beam-steering and forming antenna based on dynamically reconfigurable photo-induced Fresnel zone plates (PI-FZPs) formed by patterned illumination of a high-resistivity silicon wafer using a digital light processing (DLP) projector. This approach eliminates the need for fabrication of circuits or devices on the semiconductor wafer. Using computer-generated PI-FZPs, the beam from a diagonal horn antenna at 740 GHz has been steered from -8° to +8°, consistent with expectations from design and simulations. In addition, the antenna beam width can be dynamically tuned using PI-FZPs with different focal lengths. Both the beam-steering and forming functionalities can be performed simultaneously, enabling applications in THz communications, sensing, and imaging. The PI-FZP antenna performance and design considerations including gain, efficiency, frequency scaling and operation speed are discussed on the basis of the experimental results.