Análise de circuitos integrados e de superfícies seletivas de frequência pelo método interativo das ondas para aplicações nas faixas de micro-ondas e de Terahertz.

Abstract

The great development of the telecommunications observed in these days is mainly due to recent technological achievements and to the seeking for new facilities to make fast, efficient, and diverse communication connections among users, when and where needed. In order to get that it is necessary to develop even smaller, lighter and easy to build, as well as integrate, high frequency devices and circuits for communication systems. Thereafter it is necessary the development of high frequency devices and circuits to be used in both multiband and wideband (UWB) applications. Besides these requirements can be accomplished using microwave and millimeter wave integrated circuits due to their intrinsic properties. Therefore the analysis and proposition of new integrated circuits, like planar antennas and frequency selective surfaces (FSS) is needed and are being investigated by many researchers all over the world. This work proposes and describes the use of the Wave Concept Iterative Procedure (WCIP), an accurate and efficient full-wave analysis method, to investigate the properties of planar antennas and FSS for applications at microwave and terahertz (THz) bands. Particularly WCIP is used in this work to develop: a) new geometries for planar antennas and wideband isolated FSS, b) side by side, as well as broadside, coupled FSS, c) dual polarized FSS, d) FSS with reconfigurable geometries, and e) in a break through (step forward), optical communications geometries. The derived equations using WCIP are implemented in Matlab codes to investigate microstrip antennas and isolated and coupled FSS properties. The antenna geometries analyses are focused in the determination of resonant frequencies, bandwidths, and return loss parameters. In the case for FSS the focus is the determination of resonant frequencies, bandwidths, and insertion loss parameters. In both cases the WCIP accuracy and efficiency are addressed. Furthermore several antennas and FSS prototypes are built and measured for comparison purposes, and agreement is observed between simulated and measured results. Afterward the properties of several THz band integrated circuits are investigated through WCIP. Among them those such as: a) slot dipoles, b) collinear array of two slot dipoles, and coupled metallic ring sectors, to verify the WCIP potentiality and adaptability in analyzing THz antenna and FSS structures. WCIP simulated results are compared to those obtained through Ansoft Designer showing a good agreement.