Photonic techniques for microwave systems: application to filtering and correlation radiometers

Abstract

This thesis work has been devoted to the study of photonic techniques and devices applied to the treatment of signals at microwave frequencies, the so-called microwave photonics technology field. The benefits photonics may offer and the challenges that must be overcome to bring those to reality have been assessed and discussed. Specifically RF filtering, as a fundamental operation required on-board telecommunication satellites operating at microwave frequencies, has been identified as one key area in which contributions may be made, and a new proposal for a reconfigurable RF filter based on two tunable lasers has been studied, showing progress towards full demonstration of the practical feasibility of the filter. On the other hand, synthetic aperture radiometers in the microwave range have also been recognized as one promising area where the introduction of photonics may bring significant advantages. In this thesis a thorough state of the art review is made on the topic of photonic synthetic aperture radiometers, including the basics of brightness temperature map reconstruction through correlation of each pair of antennas in the interferometric arrangement. A new proposal to exploit the benefits of photonics into synthetic aperture radiometers has been presented and studied through numerical simulations, and its potential to improve performances in practical implementations has been assessed and compared with current proposals described in literature.