High-Q on-chip microwave resonator for sensitive permittivity detection in nanoliter volumes

This work presents the design, fabrication and characterization results for a thick film (6μm Cu), coplanar waveguide (CPW) resonator operating at 2.2GHz with a high quality factor Q (~177), integrated with a microfluidic channel. We demonstrate detection of changes in permittivity of 0.8% with a sample volume of 30nL, and estimate a lower detection limit of 0.05% (500ppm) with this device.