Picosat S band transceivers adopting off the shelf microwave components: design constraints and system level simulations

Satellite communications are at the very heart of the modern communications and their relevance is continually growing both concerning civil and military users, and considering commercial and research fields. Satellite communication has become a huge international commercial success involving budget of billion of Euros. More than 200 countries and territories rely on nearly 200 satellites for defense, direct broadcast, navigational, and mobile communications, not to mention data collection and faxing, via domestic, regional, and global links. To establish theses links so that communication assets in the networks could be effectively be operative, network, data link, and physical layers connectivity needs to be considered. Indeed, to do this we need defining the communications architecture that needs to take into account several elements such as space science orbiters, space exploration orbiters, space surface mobile and stationary vehicles, space relay orbiters, Earth orbiting relays that provide service to space systems, space Ascent and Descent modules, and associated Earth ground stations and mission operations centers. Also, communications links need to include Earth-Moon link, or any other planet links, space proximity link, space cross link, space surface vicinity link, Earth orbiting relay link, and Earth space link extension. In this thesis the physical layer is dealt in particular with the design of the RF architecture suitable for the needed hardware development. Any designed system needs to be compliant with specific features in terms of frequency bands like modulation and coding. S-band, K-band have become popular among space missions. Satellites are inseparable part of space communications, and they create a communication channel between a source transmitter and a receiver at different locations on Earth. In general, satellites are as big as the size of a small bus, but over the last twenty years, miniature satellites called CubeSats have changed dramatically the space industry,and made space access easier and cheaper. Cubesats were made possible by the ongoing miniaturization of electronics, which allows instruments such as cameras to ride into orbit at a fraction of the size of what was required at the beginning of the space age in the 1960s. CubeSats are typically built up from standard cubic units each measuring 10 cm x 10 cm x 10 cm , and the number of units depends on the CubeSat’s mission, but tends to be between 2 to 12, resulting in a mass of just 1 to 10 kg. These little satellites have a fraction of the mass, and cost, of more traditional satellites, and provide affordable access to space for small companies, research institutes and universities. CubeSats are increasingly used, and they are custom built to fulfil the specific requirements of their mission. It is necessary to be noted that putting CubeSats into orbit is not free. In the context of CubeSats, the general framework is rather variegate, however they share at least three things; first,the antenna and radio communication system, which sends and receives information to and from Earth. Second, the power source, like a solar panel or simply a battery. Third, the presence of on board computation capabilities needed to ensure the proper satellite behavior and operations. The main cubic structure is made of aluminum, and embeds the above components together with other objects such as cameras, sensors or scientific payloads. Antennas and solar panels can be installed on the exterior of the structure.