Antenna Array for a Passive SAR System

• Autor(a) principal: Ribeiro, Miguel Dias
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.26/42173
• topic: Passive Radar; Antenna Array; Patch Antenna; Chebyshev Design Method; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Eletrotécnica, Eletrónica e Informática

In this thesis, the design of an array of antennas for a passive radar system is presented. The need to reinforce the ability of monitoring the maritime space with a low-cost, low-profile and light-weight passive synthetic aperture radar (SAR) motivated this work to be assembled on an Unmanned Aerial Vehicle (UAV), so that it can track ships and other vessels by the coastline, thus preventing illicit activities. This study focuses on the design and assessment of low-profile planar antenna arrays for passive radars at ISM-band of 2.45 GHz. The analytical formulation of the design of a stand-alone patch antenna is performed, which is followed by the detailed formulation of uniform and Chebyshev antenna arrays, including their feeding network and guidelines to obtain proper impedance matching. It is well-known that uniform arrays suffer from high sidelobe level, which may affect the detection of targets. As an alternative, we focus on the design of Chebyshev arrays, in order to achieve lower side lobe level, in the interest of increasing the probability of ambiguous detections and better tracking of the targets. Both arrays are designed and optimized through full-wave simulations using Computer Simulation Technology (CST). Good impedance matching at 2.45 GHz is obtained for both numerical and experimental results. Regarding the radiation pattern, the experimental assessment confirmed the right sidelobe level for the uniform array, although there are differences for the Chebyshev due to limitations in the measurement setup. Future work should include the optimization of the sidelobe level of the Chebyshev array.