Sensitivity and Q-Factor Trade-off Analysis of MEMS Pressure Sensor for Bladder Implants

Ultra-small and highly sensitive MEMS bladder sensor has to be aligned with efficient wireless coupling to meet the requirements of minimally invasive implantation. In this study, finite element analysis (FEA) is conducted to investigate sensor's sensitivity and Q-factor on MEMS capacitive pressure sensor. The optimum geometry dimension of slotted diaphragm and square coil were analyzed in order to achieve target of high sensor's sensitivity and high quality factor with appropriate frequency sensing meant for bladder sensing application. From capacitive analysis, the optimized parameters were obtained as diaphragm area, A= 1000 um × 1000 um, air gap = 4 um and diaphragm's thickness = 4 um. The capacitive sensitivity of diaphragm is obtained = 2.22 × 10
^-1
mmHg
^-1
and sensor's sensitivity 45.8 kHz/mmHg for operating frequency in range of 55 - 62 MHz. The inductance value of 3.14 uH and Q factor of 63 were obtained at optimum value considering trade off between sensor's sensitivity and the q factor.