The design and implementation of microwave receiver front end components

[摘要] ENGLISH ABSTRACT: Different types of RF and Microwave receiver systems architectures are investigated. Thesuperheterodyne receiver characteristics are studied qualitatively. A three components system(LNA, Mixer and VeO) is selected and the components are first measured individually, and thenmeasured as a single system. A mono filar axial mode helix antenna is designed, simulated usingFEKO and constructed. A narrow band interdigital bandpass filter is designed using thecapacitance network and its transformation, and it is simulated using two different simulationpackages, eST Microwave Studio and AWR Microwave Office. Two filter prototypes arefabricated using cylindrical rods. An open circuited microstrip resonator oscillator is designedand implemented through the negative resistance method. Its performance is verified using theharmonic balance simulator in AWR MWO. A single balanced mixer is designed andimplemented using 1800 hybrid junction (rat-race) and it is also fabricated using microstriptransmission line technology. All designed components performed well in comparison to theirpredicted performance. The LNA and three of the designed components (Filter, Oscillator and aMixer) are connected together and characterized as a single four block system. The systemperformed well except for the IF signal which shift to a lower frequency due to oscillator load pulling.

[发布机构] Stellenbosch University