The capacitance is defined as the ratio of the amount of charge stored in the capacitor and the potential difference between the electrodes.
The example of a parallel-plate capacitor, in Figure1, is constructed by filling the space between two square plates with blocks of three dielectric materials.
The capacitance of each dielectric block is given by equations (1), (2) and (3):
(eq.1)
(eq.2)
(eq.3)
With the following parameters:
The equivalent capacitance is:
The following instructions show how to prescribe material to individual parts of your model and compute capacitance between two elements.
Model of the capacitor with multipledielectrics has been created in Solidworks. The space betweenthe parallel plates is filled by 3 different dielectric materials.Plate surface is , whilethe thickness of each plate is 1mm.Thickness of dielectric block
is the same as the distance between the plates: 2mm; thickness of blocks
and
is half of that:1mm (Figure 2).
The simulation is performed in the EMS Electrostatic study . Aluminum is used as a material for the electrode plates, Teflon, polyimide and nylon are used for dielectric
,
and
, respectively. All these materials with their electromagnetic properties can be found in the EMS material library.
To obtain capacitance results from EMS:
In the EMS manger tree, under Results , open the Results Table to find Capacitance matrix. EMS solution for total capacitance is
F (Figure 3) and it matches the theoretical result very closely.
Figure 3 - EMS results for Capacitance