You could try these steps:
- Double check if all necessary directories are included in the MATLAB search path. (Home > Environment > Set Path) Verify that the paths for the Antenna Toolbox are included.
- Reinstalling the toolbox can resolve missing file issues at times. You can do this through the Add-Ons manager in MATLAB.
- Make sure your MATLAB installation is up to date.
- Check for Shadowed Files: Ensure that there are no other files with the same name (EMStructure) that might be shadowing the required file. You can use the which command in MATLAB to check this:
which EMStructure -all
