Wideband Electronically Steerable Reflectarrays and Transmitarrays of Novel Reconfigurable Magneto-electric Dipoles
DescriptionTo meet the continued increase in big data traffic, electronically beam-steerable high-gain antennas are needed for future terrestrial wireless communication, sensing, radar and satellite communication systems operating at millimeter-wave frequencies. Reflector antennas and array antennas are high in gain but the directive beam can only be scanned mechanically. Although phased array antennas are electronically steerable, expensive digitally controlled phase shifters are required. This increases substantially the complexity, costs, and the physical dimensions of the antenna. The reflectarray is a promising alternative of high gain antennas. Beam scanning can be achieved by an appropriate phase compensation scheme while maintaining the simple spatial feed without the need of a complex feed network. By incorporating low-cost PIN diode switches in an array element, its reflection phase can be changed. Discrete phase control with resolution of one or a few bits can be implemented with one or several switches. The transmitarray antenna consists of an array of phase adjusting unit cells to compensate the difference in the spatial phase delay between the feed and the receiving antenna element to produce a focused beam. Owing to the advantages of planar structure, no feed blockage effect and low fabrication costs, the transmitarray is suitable for millimeter wave applications The design methodology is similar to that for reflectarrays, using diodes to adjust the phases of the unit cells. In most reflectarrays and transmitarrays, microstrip antennas are used as basic elements which are inherently narrow in bandwidth. Using a thick substrate or stacked patches can enhance the bandwidth, but the antenna efficiency will be decreased due to strong excitation of surface waves. The complexity of the array structure is also increased. The magneto-electric dipole antenna is a promising wideband antenna technology for wireless communications, sensing and radar applications at microwave and millimeter-wave frequencies. Recently, a reflectarray and a transmitarray with fixed beam of radiation employing basic magneto-electric dipoles as radiating elements were developed. Wideband and high efficiency have been demonstrated. This achievement provides the motivation to develop wideband electronically beam-steerable reflectarrays and transmitarrays using novel reconfigurable magneto-electric dipoles. The success of this project will help to enhance the performance of future commercial wireless communication and sensing systems operating at millimeter-wave frequencies, as the new technology will be very economical and affordable for many commercial applications.
|Effective start/end date||1/07/21 → …|