Theoretical Modeling and Numerical Simulation of Elliptical Capacitive Pressure Microsensor

Polymer/paper-based double touch mode capacitive pressure sensing element for wireless control of robotic arm

“…The deflection in mechanically sensitive circular shape diaphragm of capacitive pressure sensor is given by [25,26,29,39]:…”

“…The shape of pressure sensitive diaphragm is chosen to be circular due to its high sensitivity among all different shapes viz. elliptical, square, rectangular, pentagon in MEMS and paper electronics [25,36,[39][40]. In our approach, the fabrication of the sensor requires only Al coated PI sheet [h = thickness (Al and PI) = 25 µm], PI tape and double-sided tapes.…”

“…Among MEMS pressure sensor's arena, capacitive pressure sensors have several advantages like low temperature drift, high sensitivity, simple structure, low power consumption and lower sensitivity to stress at the edges of the mechanical sensitive element which will deform/deflect after pressure application [5][6][25][26]. However, the nonlinearity between capacitance change versus applied pressure and effect of stray capacitance are major issues when the pressure sensor is operating in the normal mode [21][22].…”

“…Touch-mode pressure sensors offer high pressure range, linear response and high overload protection. However, touch mode capacitive pressure sensors have disproportionate relationship between capacitance change v/s applied pressure and a short linear region which causes the sensor to reach saturation mode very fast [25][26]31]. Thus, continuous efforts have been made to develop approaches aimed at enhancing the linearity region and proportionality of capacitance variation with respect to applied pressure such as double side diaphragm touch mode [32][33], island structure sensor [34], sandwich diaphragm [35] and double touch mode [28,37] capacitive pressure sensors.…”

“…Cantilevers are mechanical elements which enhance the sensitivity of capacitive pressure sensor when it comes to measurement of small range of pressure such as acoustic pressure sensing [38]. The normal mode capacitive pressure sensor with different diaphragm shapes has been analyzed for sensitivity, and circular shape capacitive pressure sensor shows highest sensitivity, however, it shows highly non-liner response [25,39,40]. The major reason for nonlinearity is a large deflection in the diaphragm.…”