Temas do Trabalho
Os alunos podem propor temas alternativos com a aprovação do professor.
Tema 1 - Projeto de Antenas compactas
Artigo de referência: A Performance Comparison of Fundamental Small-Antenna Designs
Best, S.R. Hanna, D.L.Antennas and Propagation Magazine, IEEE
Volume 52, Issue 1, Feb. 2010 Page(s):47-70
Abstract
In this paper, the performance properties of several fundamental small-antenna designs are compared as a function of overall length and size (ka), where the antennas operate at or very near the same frequency. The objective of this work is to determine which basic design approach or configuration, if any, offers the best performance in terms of: achieving an impedance match; the radiation-pattern shape; the radiation efficiency; the half-power bandwidth; and the 2:1 VSWR bandwidth. The fundamental antenna designs studied here include the spherical folded helix, the cylindrical folded helix, the matched disk-loaded dipole, the matched spherical-cap dipole, and the multi-arm spherical resonator. In addition to discussing the different antenna designs, the fundamental approaches used in impedance matching and optimizing the bandwidth of these small antennas are described. Both numerical simulations and measured results are presented.
Tema 2 - Antena de referência para sistema de pouso por GPS
Artigos de referência:
GPS Landing System Reference Antenna
Lopez, A.R.;Antennas and Propagation Magazine, IEEE
Volume: 52, Issue: 1, Feb 2010, Page(s): 104-13
Abstract
The GPS landing system (GLS) is a reality today, and will undoubtedly become the workhorse system in the future. GPS aircraft navigation is currently utilized for aircraft en-route, terminal, and initial-approach navigation. It is expected that in 2009, a Category I GPS landing system will start its initial phase of a worldwide deployment. The ARL-1900 antenna was designed specifically to satisfy the stringent requirements for the Category I, II, and III GPS landing system reference-receiver stations. A difficult problem for a Category I, II, and III GPS landing systems is the mitigation of ground-reflected multipath effects. The antenna must provide coverage of the upper hemisphere while suppressing ground-reflected multipath. In addition, the antenna must operate at the L1, L2, and L5 GPS frequencies, have right-hand circular polarization, and ideally have constant carrier and code (group) delay throughout the coverage region. Over a period of 15 years, BAE Systems has developed the ARL-1900 antenna, a unique antenna with near-ideal performance that satisfies the stringent requirements for a Category I, II, and III GPS landing systems. This paper reviews the requirements for a GPS landing system reference antenna, presents the design principles for the ARL-1900 antenna, describes its implementation, and presents performance data.
Tema 3 -Geração automática de "mesh" tridimensional
Artigo de referência:Three-dimensional automatic mesh generation for hybrid electromagnetic simulations
Shumin Wang Duyn, J.H.
Antennas and Propagation Magazine, IEEE
Volume 51, Issue 2, Apr. 2009 Page(s):71 - 85
Abstract
Hybrid mesh generation is required for finite-difference time-domain/finite-element time-domain (FDTD/FETD) hybrid simulations. A combined approach is presented to automatically generate Cartesian/tetrahedral hybrid meshes for open and closed structures. This approach first generates a buffer zone that surrounds a target with specified tightness. The advancing-front technique with ldquosweep-and-retryrdquo is subsequently applied to generate an initial tetrahedral mesh that fills the buffer zone. Finally, the tetrahedral mesh undergoes a combined quality improvement procedure. Due to the low profile of the resulting tetrahedral mesh, the sparse Cholesky decomposition can be applied effectively to solve the resulting FETD matrix. Several examples are provided to demonstrate the main features and the performance of the proposed automatic mesh-generation method.