Millimeter-Wave Reflectarray And Transmitarray Antennas

With the development of satellite communications, wireless communications and deep-space communcations, high gain antennas have been widely investigated. The reflectarray and tranismitarray antennas originate from the phased array antenna and the reflector antenna or lens antenna, which combines their main advantages including planarity, ease of fabrication, high efficiency, low loss, and reconfigurability. Firstly, this dissertation explains the theory of reflectarray and tranismitarray antenna. Next, a new dual-resonance unit cell for reflectarray is developed and the microstrip reflectarray antennas using this element are designd. Additionally, reflectarray and tranismitarray antennas at millimeter-wave band using graphene patches instead of metal are designed. The dissertation is organized as follows:A new unit cell for microstrip reflectarray is proposed based on the theory of reflectarray antenna. With the dual-resonance of the patches and the air gap, an approximately linear phase response of range 360° can be achieved within a wide bandwidth. Using the proposed unit cells,576-element and 1296-element reflectarray antennas operatimg at Q-band are designed, fabricated, and measured. The simulated and messured results show that these two reflectarray antennas have wide gain bandwidth and good radition pattern.Based on the electrical characteristics of grapheme and using graphene-based 4-layer transmitarray unit cells, a 1024-element transmitarray antenna at 260GHz is designed. Furthermore, using graphene-based single layer reflectarray unit cells, a 2808-element reflectarray antenna at 140 GHz is designed. Simulation results show that these millimeter-wave antennas using graphene patches show good radition performance. And the whole transmitarray plane and reflectarray plane are both transparent.