For the purpose of Active Directory, I would recommend that you use the Active Directory Library rather than a Generator. In order to do a wildcard style search you can follows this directions:
1) Choose an AD Get component like "Get User with Details"
2) Goto to the "Input" Tab
3) Choose the "Set of Fields" Radio Button
4) Click on the ellipsis next to the desired field for your search (Last Name)
5) Choose "Dynamic Value" the click "Edit"
6) In the text editor, drag in the desired variable as your search and put an * after the variable (without a space) this will act like a wild card with a partial search term. For example typing "Sm" in a search box might then return all records where the last name starts with "Sm"