Mechanical Structure Design of Pressure Sensors With Temperature Self-Compensation for Invasive Blood Pressure Monitoring

Invasive blood pressure (IBP) is a fundamental part of basic cardiovascular monitoring. Conventional piezoresistive pressure sensors are limited in usage due to the high cost associated with equipment and intricate fabrication processes. Meanwhile, low-cost strain gauge pressure sensors have poor performance in the gauge factor (GF) and temperature insensitivity. Here, we report a mechanical structure design for diaphragm pressure sensors (DPSs) by introducing a compensation grid to overcome the aforementioned challenges. A simplified model is established to analyze the mechanical deformation and obtain the optimal design parameters of the diaphragm pressure sensor (DPS). By rationally arranging the placement of sensitive grids to eliminate the discrepancy of relative resistance changes within four arms of the Wheatstone full-bridge circuit, the appropriate GF and high-temperature insensitivity are simultaneously achieved. The blood pressure sensor with the DPS is then fabricated and characterized experimentally, which demonstrates an appropriate GF $(ΔU/U0)/P=3.56×10−5kPa−1$ and low-temperature coefficient of voltage $(ΔU/U0)/ΔT=3.4×10−7∘C−1$⁠. The developed mechanical structure design offers valuable insights for other resistive pressure sensors to improve the GF and temperature insensitivity.