High-frequency polarization reconfigurable microstrip patch antenna

• Main Author: Antunes, Filipa Domingues
• Publication Date: 2023
• Format: Master thesis
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/10773/41821
• topic: Reconfigurable microstrip; Linear polarization; Circular polarization; Microwaves; PIN diode; Orthogonal feed

With the evolution of wireless communications, there is a growing need for emerging technologies to move their operating bands closer to higher frequencies. At the same time, due to the exponential demand for greater bandwidth, it is imperative to consider the possible saturation of the frequency spectrum. In this context, systems that have the ability to reconfigure their characteristics become highly valued, as they make it possible to optimize the use of available frequencies. Polarization is a parameter of antennas and can be classified as linear, circular or elliptical. Traditionally, an antenna works in one type of polarization, receiving and transmitting signals exclusively with that characteristic. To operate other types of signals, a new system with the desired characteristics would be required. This work focuses on developing a system capable of reconfiguring the polarization of an antenna on the 5.8GHz frequency. To this end, in a first iteration, a structure with fixed circular polarization was developed, which made it possible to validate the choice of substrate, the antenna design method and the method used to obtain the desired polarization. The final structure developed introduced reconfigurability by switching microstrip lines via PIN diodes. These additional lines induce a signal offset at one antenna input compared to the other, which is orthogonal to it, making it possible to vary the antenna’s polarization. Finally, the practical results obtained are presented, including the Axial Ratio and radiation diagrams that make it possible to assess the quality of the polarization in relation to the signal received by the antenna in this final system.