Report from GadgetDNA says iPhone 5 may come with a aluminum made back and a redesigned antenna structure. According to the reports from a Chinese source Apple is planning to get back at the old design instead of a glass back which made several problems to the users in terms of weight and scratching issues.
The controversial issue on the iPhone 4 was its signal losing when touching the antenna. The antenna inside the iPhone 5 will be behind the Apple logo so that signals can penetrate easily. The iPhone 5 is expected to be released in June/July at WWDC 2011.