Microwave sensors based on symmetry properties of resonator-loaded transmission lines

© 2015 Jordi Naqui and Ferran Martín. This review paper is focused on the design of microwave sensors using symmetry properties of transmission lines loaded with symmetric resonators. The operating principle of these sensors is presented and then several prototype devices are reported, including linear and angular displacement sensors and rotation speed sensors. The main advantage of the proposed sensors is the robustness against changing environmental conditions.