Create a parabolic reflector on the left side of a 200 by 200 grid

Hi,

I would like to create a parabolic reflector on the left side of a 200 by 200 grid.

I need some ideas on how to implemt it.

The 200 by 200 grid has this

Row 1 numbering: 1 to 200

Row 2 numbering 201 to 400

Row 3 numering: 401 to 600

etc

I have to use this format as I will create a text file of voltage nodes to run in Pspice.

The parabolic reflector will be fixed at 0 volts.

I have created the 200 by 200 grid and put squres in there that are fixed at 0V.

Here is an example of where I am at - all straight lines:

https://drive.google.com/file/d/1eKvS-JJKNTf8oOi9EBvtzp4JLQu7u2vk/view?usp=sharing

Thanks

[Walter Roberson]

reflectorIdx = reshape(1:200*200, 200, []).';

will create a 200 x 200 matrix with entries 1 2 3 ... 200, then 201 202 203 ... 400, and so on.

[Andrew]

Hi Walter,

Thanks for that.

I have my 200 by 200 grid. I need some help to create a parabolic shape on the

left side boundary. Here is a small video I have created with a 200 by 200 grid

https://drive.google.com/file/d/1yBO-Z2PS1SqF7K9yomTMhA81HiXw7z2F/view?usp=sharing

Thanks

Andrew Thorburn

Answer 1

[Shishir Reddy]

Hi Andrew

As you have already created the 200×200 grid and set up fixed voltage nodes, refer the following steps to create a parabolic reflector on the left side.

Since you want it on the left side, you'll calculate the corresponding x-position (column index) for each y, and round it to the nearest integer grid position. Then, convert that (row, col) to your linear node index using -

nodeIndex = (row - 1) * 200 + col;

Sample MATLAB code -

a = 0.0015;  
y0 = 100;     
parabola_nodes = [];

for row = 1:200
    y = row;
    x = round(a * (y - y0)^2) + 1;
    if x <= 200
        nodeIndex = (row - 1) * 200 + x;
        parabola_nodes(end+1) = nodeIndex;
    end
end

V = ones(200*200, 1) * NaN; 
V(parabola_nodes) = 0;

This will give you a smooth parabolic curve on the left side of the grid. You can then write these node voltages to a text file for PSpice.

I hope this helps.

[Andrew]

Thanks, back to it :)