| Inmarsat is a maritime radio communication system using the maritime satellites as a relay station, which has been extended to the business areas of land and air, and become a global mobile communication system. It features high quality and large capacity, global, all-weather, and full-time. Inmarsat communication services currently supported include:telephone, fax, telex, data and image transmission. It also provides free emergency communication services for maritime distress aid and large natural disasters. Products development for these business is varied, from maritime terminals to land and air terminals. It provides users with rich choices.This thesis designs a antenna signal transmission and low noise receiver, which is the core component in the Inmarsat terminal F33 system. The receiver filters the weak radio signal which is coupled by antenna from space and sends it into the reception channel through the duplexer. LNA amplifies the signal and then sends it into FEU. In this process, the receiver isolates the transmit signal from the receive signal, reduces noise and improves system sensitivity.This thesis is composed on the basis of the ministry of transportation project "Research on Key Technologies of Ship-borne Satellite Terminal Antenna".It mainly researches on the development and composition of Inmarsat, the components and their effects of the antenna signal transmission and low noise receiver, characteristics of RF components, RF simulation software ADS2008, and theory, design procedure and engineering realization of LNA. It focuses on the design and simulation of LNA for the Inmarsat terminals F33, including the selection of the device, DC analysis and bias circuit design, S-parameters simulation of the transistor, stability analysis, matching circuit design, whole performance optimization of the total cascaded amplifier, and PCB design. Finally, the LNA and diplexer are measured, results show good performance of various aspects, and fulfill the design requirements. |
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