Dual Band CSRR Fluidic Sensor with 3D Printed Channel

A microwave band-stop filter composed of a microstrip transmission line and a complementary split ring resonator is assembled with a 3D printed fluidic channel. The resonances of the complementary split ring resonator are sensitive to the electric permittivity of a fluid flowing in its near field. Consequently, the frequency shift of the first two resonances are utilized for sensing. The design of the sensor is discussed, and a prototype is presented. The performance of the sensor is demonstrated by measuring the frequency shifts of water in function of salinity.