Low-Profile Radio Frequency Pressure Sensor Based on Additive Manufacturing Technology

Pressure sensors are used in several industrial applications spanning from aerospace to healthcare, but they often require a wired connection between the sensing part and the reader and may result bulky or with a predefined footprint. In this work, a wireless pressure sensor realized with additive manufacturing (AM) is presented. The degrees of freedom offered by AM are exploited to design and quickly realize flexible substrates that are used to transduce pressure into a shift in the frequency response of the sensor. In particular, two different polymers (PLA - polylactic acid and TPU - thermoplastic polyurethane) are investigated with different infill densities to manufacture the sensing component. The latter is wirelessly coupled with a low-profile reader represented by a high-impedance multiarm coplanar dipole. The sensor calibration curve is mapped by observing the reflection coefficient shift as a function of the variable applied pressure. Measurements assess the best performance for the PLA sensor with low infill density, which exhibits a good level of resolution.