# Help with scilab code for calculating transmission coefficient

1. Oct 14, 2011

### Reshma

I seem to be getting some arbitrary values from my Scilab code for a function. I have to generate a graph showing the dependence of the transmission on the air gap separating two higher refractive index materials i.e. I want to plot "T" as a function of "d".
$$T = \frac{1}{1 + \beta \sinh^2 (\delta)}$$
δ = 2∏d/λ

Code (Text):
d = [0:0.01:1]
delta = 2*%pi*d
T = 1/(1+0.36*(sinh(delta))^2)
plot(d,T)
xtitle("Transmission dependence on d","d","T")
The output graph does not match with what I was expecting. The transmission T should start at 1 and decrease with increasing d. Instead the graph seems reversed. I have attached the output graph file. I plotted the graph with the same formula in excel and it turns out right. Can someone take a look at my code and point out where I am going wrong.

#### Attached Files:

• ###### graph.jpg
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2. Oct 14, 2011

### bob1182006

I don't have Scilab but I think your problem is that T is calculated by matrix division not an element by element division. Other than that it seems like the code should work fine.

Try:
T = 1 ./(1+0.36 .*(sinh(delta)) .^2)

3. Oct 14, 2011

### Reshma

Wow, that worked (graph attached). Thanks a lot, Bob!

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12.6 KB
Views:
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