The design and construction of the front end section of an L-band receiver for nano- satellite application

Abstract

Optimum communication can only be achieved with a very sensitive front-end section in the receiver on a satellite because the transmitted signal from the ground station must travel hundreds of kilometres through the earth's atmosphere to a low earth orbit (LEO) satellite. This dissertation presents the design of the front end section of the receiver suitable for use in a nano-satellite. Specifically, various transistor technologies are evaluated by designing five low noise amplifiers to determine the optimum performing amplifier. The bandwidth of the front end section was controlled by designing coupled line microstrip filter. For consistency, the same design technique was followed in the design of each LNA. Simulations were performed and the results were compared to the actual measured results of the constructed amplifiers to facilitate conclusions to be made. Design specifications for the LNAs were obtained from the F'SATI Space CubeSat Programme Technical Specification document. To control the bandwidth of the front end section, various types of band-pass filters were investigated, resulting in a coupled line band-pass filter being simulated and implemented. The simulated results were compared to the measured results of the constructed filter. In the final stage of this dissertation, comparisons of each amplifier’s performance were made, resulting in the final recommendation for this project.