The mother.

Abstract

Hodoyoshi III and IV series of small satellites are scheduled to be launched at the end of year 2013. These sun-synchronous, Low Earth Orbit (LEO) satellites will perform remote sensing operations carrying with them powerful optical sensors. The huge volumes of payload data gathered from the sensors needs to be relayed to the ground station for processing and interpretation. This requires a powerful wireless transmitter with large bandwidth meeting to the power, size specifications of small satellites (< 50kg class). The purpose of this thesis is the simulation of a proposed X Band Radio Frequency (RF) Transmitter design and exploration of means to improve the design. The simulation was carried out in LabView and Matlab environment. One of the ways in which the design could be improved is found to be to perform linearisation of the power amplifier in the RF Transmitter path. The transfer characteristics of different power amplifiers were experimentally tabulated. Different digital linearization techniques were researched upon. The experimental data was further used in the simulations to test their effectiveness. Towards the end of the thesis two innovative, original models of digital linearization were proposed. The simulation results of one of the models showed very promising results. An hardware-in-loop test implementation of the transmitter is proposed, and is underway at the moment of submission of the thesis report.