Photonic and microwave techniques for sensing applications

The main objective of the research project is the theoretical, numerical and experimental study of novel techniques for fiber and microwave sensing. Regarding fiber sensors the main scope is to exploit, in an innovative way, the polarimetric measurements to improve the quality of the sensors both in accuracy and resolution by linking the physical quantities to be measured (e.g. temperature, stress, vibrations) to the changes of the random fiber birefringence and ultimately to the signal polarization. By combining polarization and power measurements several quantities could be detected at the same time. For lumped fiber sensors, the project aims at a better understanding of the polarization dependence of mechanical LPG, that are a lower cost solution with respect to FBG. In microwave sensing the objective is to exploit the microstrip patch antenna system for measuring permittivity profile in some part of industrial process such as paper mills, food production, agricultural production, etc. The basic geometrical configuration consists of transmitting and receiving antennas, and from the amplitude and phase of the received signal one should be able to determine the permittivity profile of interest. In particular, the frequency modulated continuous wave technique will be explored due to its ability to discriminate the signals in time. The antenna system should confirm to the geometry of the industrial process (e.g. pipe structure), therefore the antenna curvature and the surrounding material (measured quantity) will be taken into account in the designing process.