Reconfigurable Microwave Semiconductor Plasma Antenna

Reconfigurable antennas have been a subject of rapidly increased interest during the past decades. This has been prompted by the increased demand on new wireless communications technology in both civilian and military directions. Moreover, different types of reconfigurations have been identified and investigated to keep up with the demand for new technologies.
In this research, the possibility of designing reconfigurable Dielectric Resonator Antennas (DRAs) have been explored with different types of reconfigurability directions, especially with the increased interest in the area of DRAs during the past three decades. These results have been satisfactory in general. The main aim of this research is to experiment with different reconfigurability designs, each purpose is to achieve one type of reconfigurability or more. This includes, polarisation reconfigurability in Chapter Three, frequency agility in Chapters Four and Five, beam steering and gain agility in Chapter Five. Furthermore, this research main aim has been to investigate new ways to exploit the advantages of the semiconductor plasma in reconfigurable antennas. However, research’s limited resources led to reduce the efforts in this area to only one experiment, which is presented in Chapter Six, based on a similar design presented in Chapter Four. Although the results have been conflicted for the last experiment, the results shown that the used reconfigurability medium (AlGaN/GaN HFETs) can be benefitted better from it in other application.
Two models have been introduced for polarisation reconfigurability, a hemispherical DRA couple with reconfigurable annular slot excitation, and a notched rectangular DRA with reconfigurable parasitic strip(s). Both designs shown the possibility of achieving LP/CP radiations.
In addition, rectangular DRAs that are excited with single, as well as multiple, slot have been studied. Prototypes have been built and measured with reasonable agreement between practical and simulated results.
Furthermore, the work has been extended to study a reconfigurable DRA linear array where several designs have been investigated including single and dual-slot for two and four-element linear arrays. The single-slot model reconfiguration resulted in the expected beam steering alongside the array direction. On the other hand, both frequency tuning and beam steering have been achieved with the dual-slots models.
Finally, the semiconductor plasma reconfigurable antennas have been considered with the investigation of AlGaN/GaN HFETs as a replacement for the well investigated and presented silicon SPIN diodes. The prototype has been measure and discrepancies between measurements and simulations have been discussed.