Robust One-Tier Calibration for Microwave Microfluidics using Unknown Liquids

Microwave measurements in microfluidic systems require accurate calibration methods. Unfortunately, this is inherently ill-conditioned problem prone to any error sources. This work presents a robust method of one-tier calibration, which minimizes the uncertainty by requiring only one connection. The calibration standards are realized by flushing different liquids through the microfluidic channel. The electrical parameters of these liquids do not have to be known, as they are determined during the calibration procedure. This alleviates the requirements for the manufacturing process, liquid purity, and measurement conditions, which is shown to significantly decrease the calibration error when comparing to corresponding method assuming perfect knowledge of standards.