  A lot of work on clamped circular, square and rectangular shaped capacitive
pressure sensor has been carried out. However, to the best of our knowledge, no
elaborate work has been performed on mathematical formulation and simulation of
clamped elliptical shaped capacitive pressure sensor in literature. This paper
describes the mathematical modelling and simulation of normal mode clamped
elliptical shaped capacitive pressure sensor. The study of various performance
parameters like maximum diaphragm deflection, capacitance variation, mechanical
sensitivity, capacitive sensitivity and non-linearity is also carried out for
operating pressure range of 0 kPa to 18 kPa. For circular capacitive pressure
sensor, the operating pressure range is modified according to physical
dimensions i.e. thickness and radius of diaphragm, separation gap between
plates and maximum deflection. For same overlapping area between plates
(10000*pi mm2), the comparison of elliptical shapes of different eccentricities
with circular shape diaphragm is carried out. The thickness of diaphragm is
taken as 2 um and separation gap is 1 um in all the designs which are used in
this work. In this comparative study, it is observed that elliptical shaped
capacitive pressure sensors have better linearity than circular diaphragm
pressure sensor.
