Gautam_Bhattacharya:

I have to features maps


Do you mean “2”. Something is wrong in your description.
2 feature maps of size (32, 64, 10, 10) = 2 x 32 x 64 x 10 x 10 elements = 409600 elements
1 output of size (32, 64, 20, 20) = 32 x 64 x 20 x 20 elements = 819200 (double the previous)
So any way of concatenating 2 inputs with that size won’t give you output of desired size (unless you’re adding elements from somewhere else)
Did you mean concatenating 4 inputs?