This dissertation presents high-efficiency 1-bit reconfigurable reflectarray antennas (RRAs) based on metasurfaces. The PIN diode-based 1-bit RRAs have the potential to be an alternative to conventional phased array antennas due to their tremendous ad...
This dissertation presents high-efficiency 1-bit reconfigurable reflectarray antennas (RRAs) based on metasurfaces. The PIN diode-based 1-bit RRAs have the potential to be an alternative to conventional phased array antennas due to their tremendous advantages in various perspectives, such as gain, weight, size, cost, manufacturing, simple control unit, and fast on/off switching speed.
First, a brief history, background, and characterization of metasurfaces are introduced. The characteristics of passive RA and RRA are reviewed by comparing the unit cell structure, and the scope of this dissertation regarding PIN diode-based RRAs is presented.
Second, the principle of designing RRAs with high aperture efficiency is introduced. Aperture efficiency is analyzed by separating it into factors, such as spillover, illumination, element, quantization, and others. Elaborate studies on feed configuration, phase-controllable unit cell, and beam steering with phase quantization are performed to achieve high aperture efficiency.
Third, a wide-angle and high-efficiency RRA based on a miniaturized radiating element is presented. Based on array antenna theory, wide-angle beam steering is achieved using a miniaturized ring patch element with a wide element pattern. This RRA is designed with a low-profile feed configuration, and the quantization efficiency is maximized by considering the reference phase and asymmetric phase difference.
Lastly, a dual-polarized RRA based on a symmetrically rotated sub-array is presented. In this design, a miniaturized rectangular unit cell is employed to generate pure single-polarization, and a dual-polarized metasurface is designed by arranging them alternately. In addition, adopting a symmetrically rotated sub-array significantly suppresses the cross-polarization levels and slightly improves the peak gains.
The proposed RRAs with high-efficiency are expected to have potential as an alternative to conventional phased array antennas in areas such as radars, satellite communications, and 5G or 6G communication base stations, etc.