Optimized electromagnetic interaction microwave resonator/microfluidic channel for enhanced liquid bio-sensor

This paper presents a study to enhance the performances of a microwave microfluidic resonant-based biosensor by optimizing the coupling between the liquid under test and the electromagnetic fields. Simulations and measurements show that two mechanisms take place: strong coupling makes the sensor very sensitive but characterized by a degraded quality factor, which increases the measurement uncertainty. Conversely, weak coupling reduces losses but decreases simultaneously the sensitivity of the sensor. To cope with this tradeoff, repeatability investigations have been performed and outline that the stronger the coupling, the better the resolution, offering an unambiguous design guideline.