Studying the CMB Polarization. Calibration and First Observations of the QUIJOTE 30 and 40 GHz Instruments

Since its discovery in 1964, the Cosmic Microwave Background has been a crucial source of information about our Universe and a huge effort has been made to produce increasingly detailed maps of the CMB temperature field. The next frontier of CMB research involves measurements of its polarization, i.e. the orientation of the light perpendicular to the direction of propagation, which was first detected in 2002. The possibility to constrain some theories about the Universe evolution at a very early times, made the CMB polarization measurement one of the most discussed and challenge future objective in Physics. In this work, we will treat the argument from two different points of view: in the first two chapters we will explain how the CMB polarization is related to some Cosmological theoretical frameworks and we weill dedicate the last three chapters to the past and actual CMB experiments, moreover, my contribution to the QUIJOTE Experiment. The work comes from the experience mad at the University of Padova with Professor Sabino Matarrese, who provided me the theoretical tools to deeply understand the subject, and the collaboration with Professor José Alberto Rubino Martin and the QUIJOTE group, who showed and introduced me to the world of experimental research.