You can easily create new tabs / menu pages almost everywhere in the Kentico CMS.
- Go to the Modules application and edit the Content module
- Select the User Interface from the side menu
- In the tree view select CMS > Administration > Content management > Pages > Edit
Now you can add a new page which you could use for your custom 'tab'.
Using the Visibility condition of that new UI element (tab), you could make sure it only shows for you articles page type.
Using the visibility condition of the page type fields you only want in your custom tab, you could hide them from the normal form tab. Make sure they aren't required.
You must create your own code to show the page and make the fields of the page type editable. So except from the UI configuration it's not really out of the box. As Brenden mentioned depending on your scenarios working with the visibility condition on the form tab itself might also suit your needs.