How to write a Matlab code for n-coupled transmission line using FDTD

Hello,

I wrote a code for 2 couple transmission line using FDTD in Matlab, which is working. But when I tried to write the code for 3 or more coupled lines its not working.
Please help me . Thanks in advance

Based on the information you've provided, I've determined that your problem is that your FDTD code does not work for systems with more than two conductors.

Thank you sir,

Can you please give me any suggestions to write the code for more lines?

I suspect maybe that third conductor is too close to a boundary or perhaps even embedded in a PML. Check your grid for proper spacing of everything.