Hello, current members of the forum!

I was wandering, what would be an example of when you use complex numbers in matrices when dealing with electronics? I believe that you actually would never have to do so. You would use complex numbers when dealing with AC or electromagnetics to express two-dimensions that alternate: direction and amplitude, but you wouldn't need matrices...

But when would you use complex numbers in matrices for electronics? I can't think of any, but to be sure, does anyone know?