I am trying to write a program to numerically calculate RCS using geometrical optics (or some form of it). Basically my idea was to cast a bunch of rays from an emitting object (in my code it is a 1 m^2 plate), find where they intersect a surface, reflect the rays off of this surface and see if they intersect the emitter again (monostatic RCS).(adsbygoogle = window.adsbygoogle || []).push({});

The rays take the form:

[tex]u=\vec{A}e^{iks}[/tex], where [tex]k=\lambda/c[/tex], and is a vector amplitude representing the electric field, and s is path length.

Basically I sum all outgoing rays:

[tex]E_{transmit}=\sum{u_{transmit}}[/tex]

and

incoming rays:

[tex]E_{receive}=\sum{u_{receive}}[/tex]

Basically I have a Monte Carlo integrator spit out rays randomly, which are added to [tex]E_{transmit}[/tex], specularly reflected over geometry and added to [tex]E_{receive}[/tex] if they bounce back and hit the emitter/detector geometry. This iterates until [tex]E_{receive}[/tex] converges (also at least 1000 runs are performed). Now, I know it converges because I can run the program over and over again and get roughly the same answers with less and less variation depending upon my acceptable error value.

After I have a value for [tex]E_{receive}[/tex], I then take:

[tex]RCS=(|E_{receive}|^2/|E_{transmit}|^2)[/tex]

Now, when all outgoing rays are reflected back to the transmitter, I get a value of 1.0. This was my test case for a 1 m^2 flat plate parallel to the emitter, with all rays traveling along the z axis- basically perfect directivity in a sense. If I let rays scatter along a hemisphere and attenuate them based on pointing error, I get a lesser value, but still a sane value. This makes sense to me. However, I have yet to figure out how exactly to convert this square meters.

Aerospaceweb.org gives an RCS equation of:

[tex]4\pi a^2b^2/\lambda^2[/tex]

This of course, does not match my results, but I think that's because I am quantifying my RCS much differently.

So in short, my questions are:

Does my method seem to make any sort of rational sense? (My training was in aerospace engineering, not electrical engineering, so I don't know these things)

How do I go from received E field magnitude to an RCS in square meters?

Thanks.

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