1) Starting
PDE tool box
2) Selecting
application for
electrostatics
3) Grid and Axes Settings
4) Drawing Shapes
a)
b)
Select shapes either from the
menu or tool bar
5) Double click shape to
change its properties
6) Coaxial Cable
• MATLAB works on a union/subtraction
method to create the 2D space which
we want to simulate
• ‘+’ is a union of the 2 shapes
• ‘-’ is the removal of 1 shape from the
other
Eg. For the coaxial cable. The area to be
simulated is the space between the 2
conductors. Here we have E2-E1. The
simulation space is the circle area E2
with the core (E1) removed
7) Specify boundary
conditions
Set the inner
boundary potential
(r) to 10V and the
outer boundary to 0V
Leave h as 1
You can select
multiple boundaries
by holding down the
shift key
Double click on
boundary to change
its properties
8) PDE Specifications
•Assume epsilon = 1
•Set rho = 0 because there is no charge
in the space between the conductors,
hence no charge density
9) Meshing
Initialize mesh
refine mesh
The more you refine the mesh, the better the accuracy but the longer the simulation time
You can also Jiggle the mesh which will reorder meshing
10) Solve PDE
You can read the value of the electric potential by
click and holding any point on the simulation space
11) Plot parameters
Changes the plot displayed after
solving the PDE
You can switch between steps and change your simulation anytime by
going to the menu and selecting the desired “Mode”
2-Wire Transmission Line
To simulate the region around the 2 wires E1
and E2, we need a third box, “R1” , to
delineate this space.
Region of interest is hence R1-(E1+E2)
2-Wire Transmission Line
We need R1 to create the simulation space
but we DO NOT want it to be a boundary with
voltage.
To do this set h=0 for the 4 sides of R1