Integrating 3D Printed Microfluidic Channels With Planar Resonator Sensors for Low Cost and Sensitive Liquid Detection

Planar microwave resonators interact with materials in their vicinity through the electromagnetic field alteration caused by the materials’ molecules. In this work, we are presenting 3D printed channels integrated with microwave planar resonators for inline and real-time liquid sensing applications. The designed structure operates at ~ 4.6 GHz with quality factor of 96. The implemented sensor structure provides a low-cost, high yield, inexpensive and robust sensing platform within a thermal operation range of 0 to 90°C. The fabricated sensor demonstrated a distinct difference between sample liquids flowing through the channel and was consistently able to detect an ethanol concentration of 0.4% in water at room temperature. The implemented sensor has footprint of 4×5 cm2 with a short preparation time.