Coding metasurface based pattern reconfigurable antennas with linear and circular polarization characteristics

Abstract

Future wireless communication systems require Reconfigurable Antennas (RAs) to address newlinethe limitations of conventional antennas. While conventional antennas offer simple newlinedesign, low cost, and low power consumption, they are constrained by fixed radiation newlinepatterns, narrow bandwidth, and limited gain. In contrast, RAs provide dynamic newlinecontrol over frequency, radiation pattern, and polarization, offering enhanced flexibility newlineand adaptability to meet evolving communication needs. newlineThis thesis focuses on the design, development, and experimental validation of an newlineinnovative Transmissive Coding Metasurface (TCMS)-based Pattern Reconfigurable newlineAntenna (PRA) with both linear and circular polarization characteristics operating at newline3.5 GHz, making it highly suitable for 5th Generation (5G) communication systems, newlinesatellite communications, and radar systems. Metamaterials are artificially engineered newlinematerials with unique Electromagnetic (EM) properties that do not exist in natural materials. newlineThese properties arise from their subwavelength structures. A metasurface is the newlineTwo-Dimensional (2-D) counterpart of a metamaterial. Like metamaterials, metasurfaces newlinecan exhibit special EM properties, such as negative permittivity and permeability. newlineWhile metamaterials are Three-Dimensional (3-D) structures, metasurfaces are composed newlineof thin, flat layers, making them easier and more cost-effective to design and fabricate. newlineThey consist of a planar array of subwavelength elements that manipulate EM newlinewaves at the surface level. Despite their simpler structure, metasurfaces can perform newlinemany of the same functions as metamaterials. The proposed antenna designs integrate newlineTCMS with conventional antennas, Artificial Magnetic Conductor (AMC), and a novel newlinecontrol circuit board to achieve beam steering and beamwidth reconfigurability under newlinelinear polarization. The concept is further extended to a dual-polarized TCMS integrated newlinewith Circularly Polarized (CP) antennas, AMC, and a 3-dB hybrid coupler to newlineenable beam steering with circular polarization charact