# Efficiency calculation of PML Boundary..

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#### milli

##### Junior Member level 2
pml boundaries

hi everyone..

in my project i am working with FDTD simulations with PML boundaries..
i am new to these topics..

can anyone explain me... how to find "EFFICIENCY OF PML"..

any material related to this will also be appreciated

pml boundary

#### rrumpf

##### Full Member level 5
pml boundry

The "efficiency" of a PML is simply how much energy it absorbs (does not reflect) relative to the energy incident on it. You probably want to study how its efficiency is affected by angle of incidence, background material properties, frequency, etc.

While there are many way to set this up, here is one possible recipe. For simplicity I am assuming you want to do a 2D analysis of PML efficiency.

1. Setup a small problem space where the dielectric constant and permeability are all set to 1.0.

2. Use periodic boundary conditions on your x-low and x-high boundaries.

3. Use a PML boundary condition on your y-low and y-high boundaries. This will be what you test.

4. Use the total-field/scattered-field formulation to inject a one-way source into your problem. Set the amplitude 1.

5. Run your simulation and record the power reflected by the PML, Pref.

6. Calculate the power in your source (Pinc).

7. Calculate the "efficiency" of your PML: Eff = 1 - (Pref/Pinc)

8. Run your model to sweep frequency, angle of incidence, background material properties, etc.

Hope this helps!
-Tip

#### milli

##### Junior Member level 2

and i would like to know few things like....
what are the factors tht effect the efficiency..?

and may i know whether you have worked on this topic before ??

Regards,
milli

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