Good Web Designer is a very simple software for creating ad banners specially for google ad words and double click studios. Google Web Designer provides option to create responsive ads , This software is very simple to use they are optimized for google adwords and double click studio . However google web designer is still in beta version and i don’t think it is under development any more. Since a banner doesn’t require much this software can be good enough for you to create simple ad banners. Google Web Designer provides limited animation option. Their timeline is simple.