Drawing mutiple circles at different locations using shader

Hey,
I'm new to unity and shaders and I really need some help.
I need to have some circles at different locations of different radius. I want to provide radius and location programmatically by C#.

The color of entire shader will be the same but the alpha will be different, circle will have zero alpha(would be better it has some drop-off).
I have added an image with single circle(background was kind of blue, the inner side of circle is having alpha lesser then outside of circle) but all I need is multiple circles.

Thanks for the help.
Sorry if repeated the question

 

Is it possible to pass arrays from unity to shaders?

 

It is. In 5.3 and earlier you have to pass each element of the array using the name of the array and a number, i.e.:

C#:
for (int i=0; i < myVectorArrayValues.Count; ++i)
myMaterial.SetVector("_myVectorArray" + i, myVectorArrayValues[0]);

ShaderLab:
uniform float4 _myVectorArray[50];

In 5.4 they added SetVectorArray so you can just do:
myMaterial.SetVectorArray("_myVectorArray", myVectorArrayValues);

Note that the arrays in the shader are a constant size. If you'll either want to always pass an array from C# that matches the size of the array in the shader and fill the unneeded entries with valid data you can test against to skip, or you can set another property to let the shader know how many elements to iterate over.