Abstract
We present a low-cost pressure transducer for medical applications. It’s based on the radial expansion of a liquid filled elastic
tube, which is detected by a capacitive measuring principle in a non-contact manner. For optimization we investigated the
influence of the number and arrangement of the measurement electrodes, their length as well as the gap separating them. The
optimized electrode geometry features a sensitivity of 0.195 fF/103
Pa and a corresponding mean coefficient of variation (CV) of
6.4% considering three individual transducer assemblies. The transducer performance was investigated applying pressures up to
50 x 103
Pa. Due to a viscoelastic behavior of silicone material we determined a hysteresis effect which implied a maximum error
of 1.13 fF implying a pressure error of 5.8 x 103 Pa.