Modelling and Simulation of a portable, size- discriminating Capacitive Particulate Matter sensor

Comparison of Analytical and Numerical Methods of Obtaining Coplanar Capacitance of Microelectrodes for Particulate Matter Detection

“…Single silica-glass particle of $ = 3.75 and diameter 1.5 µm was used in this simulation. The capacitance jumps obtained is shown in Fig 4. From this, it can be deduced that the active volume changes with the dimensions of the electrodes and, in this case, the particle cannot be detected above 4µm compared to 18µm in [5], [14]. The highest capacitance obtained was 2.3 aF, which reduces rapidly with height above the microelectrodes.…”

“…The Fig 4. -Capacitive jumps detected for single particle falling vertically on the microelectrodes. model was developed using the methods specified in our recent work [14]. The particle trajectories obtained are shown in Fig 3. The time steps show the progression of the particles in a MEMS-based device, discriminated by thermophoresis and deposited on different electrodes.…”

“…While conformal mapping approaches are suitable for measurements with high enough signal level such as contacts [15], for high sensitivity measurements such as in portable or Micro-Electromechanical Systems (MEMS)-based capacitive PM sensors [5], [14] where signal levels can be as low as few tens of zeptofarads to a few attofarads, a difference in estimation of the order of a few femtofarads is too large, therefore, conformal mapping approaches may not be suitable. Further, a comparison of the results of each approach is necessary to inform of their limitations in application.…”