Complex-Valued input to CNN
There has been some research in building very specialized deep learning models to use complex numbers using complex algebra, but these tools are not yet user-friendly. So unless you want to go down the rabbit hole and try to understand their implementations and then try to write your own implementation, i would avoid this. 

In the past, I worked with MRI data which is a 3D complex-valued matrix. I inspired myself from the work done in color images, where 3 channels are used to represent red (R), green (G) and blue (B). I this separated the real and imaginary part, and treated them as separate channels into the deep learning model all as real numbers.

1D example:

From a complex vector, we get 2 channels where the imaginary part can then be treated as a real number. 

$[1+1j, 2+2j, 3+3j] = [1, 2, 3], [1, 2, 3]$